Archive | Brakes

Why I Choose Centerpull Brakes

When I spec’d my new bike for this year’s Paris-Brest-Paris (and for our adventures in the Cascade Mountains), I opted for centerpull brakes. I didn’t choose centerpulls out of nostalgia. For the riding I do, they are the best choice.

Why not dics brakes?

It’s undeniable that the best hydraulic disc brakes offer amazing braking power. Isn’t more braking power always better? There is a limit to how much braking power you can use. Once your rear wheel lifts even with your weight all the way back, you can’t use any extra braking power. A good centerpull brake has just enough power to lift the rear wheel.

If the ultimate braking power is similar, then the choice of brakes comes down to other factors. For me, it’s about the fork rather than the brake itself: Disc brakes feed the braking forces into the left fork blade and flex it backward. If the fork isn’t stiff enough, the bike will self-steer when you brake hard. I once rode a test bike with a Wound Up disc fork that required a quick flick of the handlebars every time I braked hard, to compensate for the fork twist. It became second nature, but many riders might not like this.

Modern disc forks are much stiffer and no longer self-steer. The down side is that this stiffness transmits road shocks that are too big for the tires to absorb. Well-designed steel forks with thin blades flex up to 15 mm (0.6″), just enough to take the edge off these bumps. That’s not just more comfortable, but also faster.

There other reasons why I don’t like disc brakes, but they are relatively minor. One is weight – rotors, calipers and long brake lines all add up (although that can be mitigated somewhat if you use carbon rims.) Discs tend to bite quicker in the rain, but most discs I’ve ridden howled terribly when wet. Discs require more maintenance and care – the hydraulic houses are prone to kinking, and the pads often rub noisily on the rotors, requiring frequent adjustments of the calipers to recenter them. (Thru-axles have helped with that.)

Disc brakes have their place: They are an excellent choice for bikes with very wide tires. They don’t have to reach around the tire, so the brake’s weight and power are independent of tire width. That is why mountain bikes use them. With front suspension, the stiffness of the fork blades is a non-issue. On modern production bikes with wide tires, disc brakes make sense: They are what is available, and they work well. Simply choose the widest tires you can run, and you’ll get plenty of shock absorption.

For custom bikes with moderately wide tires, I think the main reason riders are tempted by discs is simply this: Most rim brakes for wide tires weren’t very good. But those problems can be overcome.

Why not cantilevers?

Our Rene Herse cantilevers are among the lightest brakes in the world. At 75 g per wheel, they weigh far less than most racing brakes. We used them on the J. P. Weigle for the Concours de Machines Technical Trials in France. They brake very well, too – as I could confirm when descending from the mountains in pouring rain during the Concours.

We’re very proud of our Rene Herse cantis, but I still prefer our centerpulls. The inherent drawback of all cantis is the location of the pivots on unsupported section of the (relatively thin) seatstays and fork blades. When you brake, the brake cable pulls upward, which tends to splay the brake posts outward. In addition, the pads are dragged along by the rim, which also tends to twist the brake. On the front, these two factors reinforce each other.

The fork blades twist, and this changes the angle at which the brake pads hit the rim. That is why you toe in the pads, which reduces the effect. But there is still a non-linearity as the pad surface increases as you brake harder.

For most rides, it’s not a huge deal, but when you brake deep into turns during twisty mountain descents, a brake that responds linearly to your input gives more confidence. And in the Cascade Mountains, we have plenty of twisty descents. When curve follows upon curve, when your instincts take over and your bike feels hardwired into your brain, then you want a brake that responds with linear force to your inputs. A brake where each increment of lever pull results in the same incremental increase of braking force.

That is where centerpulls come in. They eliminate the twisting problem by locating the pivots above the rim, where the stays (rear) and fork blades are well-braced. The result: There is no twist, the pad angle doesn’t change, and the brake action is linear and easy to modulate.

Modern racing brakes use the same pivot location – only the upper arms are more complex to eliminate the need for a straddle cable. Many of the best bikes now have direct-mount brakes, where the pivots are part of the frame, which further reduces flex (and weight). When we reintroduced direct-mount centerpull brakes, they were seen as oddballs. Today, they have become the norm.

Straddle cables have fallen from favor because they can cause lost motion. A thick straddle cable, as in the photo above, tends to curve over the straddle cable yoke. When you pull on the brake lever, the first part of the lever travel only pulls the straddle cable straight, without actually slowing you down.

Lever travel limits the power of all brakes: In theory, you could make the brake more powerful by increasing its mechanical advantage, but then the pads travel less for each increment of lever travel. And you can only pull the lever so far until it hits the handlebars. If you are wasting some of the lever travel to pull the straddle cable straight, you have less left over for the actual braking. You have to design your brake with less mechanical advantage – less braking power. And/or you need to set the pads closer to the rim, which increases the chance that they’ll rub if your wheel goes slightly out of true or if your brake goes slightly out of adjustment. (That is why discs tend to rub: They have a lot of mechanical advantage, so the gap between disc and rotor has to be tiny.)

There is a solution:  Use a thinner straddle cable that doesn’t bow. The straddle cable transmits less force than the brake cable, so a thinner cable works fine. (We use a derailleur cable, so replacements are easy to find.) The thinner cable bends smoothly around the straddle cable yoke (above). There is no lost motion when you apply the brake. Without the risk of bottoming out the brake lever, we had the freedom to design the Rene Herse brakes with more mechanical advantage. That way, we get as much brake power as a very good mechanical disc brake.

All the mechanical advantage in the world doesn’t do much if the brake flexes instead of squeezing the pads. Brake flex means less power for slowing the wheel. Most of the flex occurs between the pivots and the pads. This part of the brake twists when the pads are dragged along by the rim. The upper arms can be thin: They are stressed mostly in one plane (up/down). That is why centerpull brakes can be superlight: Their pads are much closer to the pivots than those of old-fashioned sidepull and dual-pivot brakes.

Not all centerpull brakes are created equal. The arms of our Rene Herse centerpulls have been optimized using Finite Element Analysis. We forge the brake arms for optimum strength, so we can make them thinner and lighter than CNC-machined arms. In fact, Rene Herse centerpulls are among the lightest brakes out there.

All our brakes are now available with titanium eyebolts for the pads. The centerpulls weigh just 137 g (per wheel, with pad holders, but without pads*). That is the same as a direct-mount Dura-Ace brake, even though the Rene Herse has room for 42 mm tires and fenders, while the Dura-Ace clears just 28 mm tires (without fenders).

For the titanium version of our brakes, we’re also using a titanium lower bolt for our Straddle Cable Yoke to save further weight. (The upper bolt is always made from super-strong CrMo steel, since it secures the brake cable.) The steel-bolt version of the brake remains available as a more affordable option.

The new custom-made titanium bolts are available separately, too. They are great for attaching bottle cages and fenders. (Please don’t use them on racks, where the full strength of steel bolts is needed!)

Light weight, excellent power, great modulation, low maintenance, and the ability to use flexible fork blades for comfort and speed – those are the reasons why I chose Rene Herse centerpull brakes for my new bike.

Further reading:

* Rather than get into a competition for the lightest (meaning: thinnest) brake pads, we weigh our brakes without pads. That way, we can use thick brake pads that last three times as long as the thin pads of most modern brakes. If you want ultralight pads, you can cut them down (or run well-used pads).

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Disc Brakes in the Tour de France


This year’s Tour de France has had its share of drama, and the winner won’t be the one most observers predicted. Among the sporting achievements, the technological innovation was easy to overlook: Finally, the UCI approved disc brakes, and the Tour is the first big stage race where they’ve been used.
Reading the previews of Tour bikes, it sounded like all racers would make the switch. Just in time for the big race, several big bike manufacturers rolled out new race bikes with disc brakes that approach the UCI-required minimum weight. With no weight penalty to speak of, adopting disc brakes seemed like a no-brainer.

After all, brakes are maybe the most important components of a racing bike. When Mafac introduced their first centerpull brakes in 1952 (above), it didn’t take long until almost all racers adopted them, so superior was their performance. It didn’t matter whether they rode for French, Italian or even the ‘International’ teams – braking hard before the corners was more important than allegiance to national sponsors. And when Campagnolo rolled out their sub-optimal ‘Delta’ brakes, racers refused to use them. Campy backpedaled and resurrected their old sidepulls in a hurry. With disc brakes being heralded as the most important innovation in decades, most expected shiny metal circles to appear on the hubs of the entire peloton.

And indeed, during the first stages, most teams rolled out on bikes with disc brakes (above the finish of Stage 5). Ironically, most of the disc brakes were on aero bikes used for flat stages, where brakes make no difference in the bike’s performance.

As the race continued, most racers quietly switched back to rim brakes. The yellow jersey contenders had used rim brakes from the beginning. Why?
The racers were concerned about flats. Through axles require extra time during wheel changes. Worse, the inevitable manufacturing tolerances change the alignment of the disc rotors on different wheels, even if the same model of hub is used. Unless the disc calipers are adjusted, the new wheel’s rotor will rub. (We realized this during our most recent tire tests, where we thought we could speed up the changes between different wheel sizes, but had to adjust the disc brake calipers after every run.)
BMC Racing found a work-around solution to the problem: When a rider flats, they don’t change wheels, but the entire bike. However, this also means they no longer can use neutral support. Most other teams weren’t willing to run that risk.

When the Tour entered the mountains, many observers expected the racers to switch back to disc brakes.

If disc brakes have an advantage, it’s on the vertiginous descents of the Alps and Pyrenees. Since racers have moved to wider tires with more grip, descents have become much more exciting, with higher speeds and more attacks than in the past. Braking is more important than ever. And yet, there was hardly a disc brake in sight.

What happened? I asked a former mechanic of the French national team. He indicated that the introduction of disc brakes was due to sponsors’ demands. With the big component and bike makers pushing discs, it was useful if pro racers used the new technology.
So why did the racers use rim brakes when their sponsors wanted them to use discs? If discs were superior, racers would have used them, especially in the mountains. After all, a real advantage on the many descents of this year’s Tour would have outweighed the relatively small risk of losing time due to a wheel change.
The answer is simple: Really good rim brakes stop just as well as even the best disc brakes. And many riders find that rim brakes offer superior feel: The brake lever is directly connected to the rim via a cable, rather than having the feedback dulled by the wind-up of the spokes and by hydraulic fluid. It’s refreshing that even today, where bike racing has become big business, winning races still is more important than pleasing sponsors.

In the future, I expect that the problems with wheel changes will be overcome by standardizing the disc location. A friend has already done this, using thin washers to make sure all his wheels fit all his bikes without adjusting the brakes. It’s a lot of work, and team mechanics will not be happy…
Rotors will also have to be standardized – currently, teams use both 140 and 160 mm on the front – to simplify neutral support. And then, the sponsors finally will be able to showcase bikes with disc brakes in the Tour. For now, it’s clear that disc brakes don’t offer a big advantage over the best rim brakes.

Back in 1952, it was different: Centerpull brakes swept through the pro peloton. With their pivots placed next to the rim, they offered greatly superior stopping power and modulation to previous brakes. In fact, the rim brakes that dominated the 2018 Tour de France use the same principle – only the actuation is different to eliminate the need for straddle cables and cable hangers.
Further reading:

Photo credits: A.S.O./Tour de France.

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Myth 12: Disc Brakes Work Better Than Rim Brakes


To celebrate Bicycle Quarterly‘s 15th anniversary, we are looking at myths in cycling: things we used to believe, but which we’ve since found not to be true.

Disc brakes have become popular on allroad bikes for a variety of reasons. One of them is that they are perceived as offering superior braking. It seems to make sense – after all, disc brakes on cars and motorbikes revolutionized braking performance. Why wouldn’t they do the same on bicycles?

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Introducing René Herse Cantilever Brakes


The new René Herse cantilever brakes are here! Prototypes of these brakes were one of the secrets that made Peter Weigle’s bike at this year’s Concours de Machines so light. They weigh just 75 g per wheel including bolts, springs and pad holders (without pads).
How can the René Herse cantilever brakes be that light? After all, even carbon cantilevers like the TRP RevoX are 50% heavier at 113 g. The TRP shows what happens when you take a standard brake and try to make it lighter – there is only so much you can do.

The secret of our new cantilevers is simple: They are different in many ways from most current brakes. The credit goes to René Herse, who designed these brakes for the 1940s Concours de Machines technical trials, where his bikes were among the lightest ever made. And yet his brakes weren’t just for weight weenies – they even equipped his tandems. I’ve ridden Herse tandems in the mountains, and the stopping power of the brakes was definitely sufficient.

How do you make a superlight brake? You start with an absolutely minimalist arm. Ours is forged from aluminum for ultimate strength.

Just as important is the shape – we used Finite Element Analysis (FEA) to model the stress distribution in the arms (above). Blue and green means low stresses. As you can see, Herse’s original design showed no stress concentrations. (The small spot of red is caused by a lack of reference points near the edge, not because the arm is likely to break there.) The FEA model confirms the genius of the ‘magician of Levallois,’ who didn’t need computers to make parts that were light and strong.

The arms are so minimalist that there is nowhere to attach the springs. Drilling holes would weaken the arms, so the springs wrap around them instead. You’ll also notice that there are no screws to dial in the spring tension. They aren’t necessary, because our springs are carefully equalized. You only need to adjust the tension if one spring is stronger than the other – which unfortunately is the case on many cantilevers. Making springs to such close tolerances is more expensive, but it also makes setup easier.

René Herse used post-style pads. (In fact, he may have invented them – earlier cantilever brakes used the same pads as sidepulls, which attach directly with screws.) The advantages of post-style pads are many. First, it makes it easy to adjust for pad wear – you just slide the pads inward. This means that the brakes fit on bikes with a wide range of canti post spacing. The posts also allow adjusting for minor variations in canti post height (as you slide the pads inward, the arm rotates outward, which lowers the contact of the pad on the rim.)
Post-style pads make it possible to make the arms lighter, because they don’t need flat spots with slots where the pads attach. Herse used large eyebolts to attach the pads to the arms. This is one place where our new brakes are even lighter than the originals: Optional titanium eyebolts for the pad holders save weight without sacrificing strength – these bolts are large to fit over the pad holder posts, not because they have to withstand big stresses.

To adjust the toe-in of the brake pads, René Herse simply bent the arms. That worked for him, because his brakes were used only on custom bikes, which were set up in his shop by experienced mechanics. The advantage of this method is that you only bend the arms once, and the toe-in is set forever. Later, you can replace the brake pads without having to set the toe-in again.

For our new brakes, we offer the option of angled washers that let you set the toe-in (part 28/28T, shown above in blue). This is super-simple and permanent, too, so pad replacement is easy. Since the washers take up extra space, we replace the large aluminum nut on the eyebolt with a shorter steel one. The weight goes up a fraction (4 g), but it’s a great solution for customers who aren’t comfortable bending their brake arms, or for brakes that may be used on many different bikes. (Bending the arms too often can weaken them.)

Like our centerpull brakes, the new René Herse cantilevers use an extra-thin straddle cable. This is made possible with swiveling attachments to the arms, which eliminate stresses to the cable that occur with standard clamp bolts. The thinner straddle cable isn’t just lighter, it also bends more easily around the straddle cable holder. This eliminates the flex you get with thicker straddle cables, which have to straighten first when you apply the brakes, before they can transmit brake power. The thinner straddle cable makes the René Herse brakes more powerful, yet the minimal ‘lost motion’ allows you to set the pads with plenty of clearance to the rim – without the risk of bottoming out the levers. This also means that the René Herse cantilever brakes work equally well with modern ‘aero’ and with classic ‘non-aero’ brake levers.

We’ve tested the new René Herse cantilevers on a variety of bikes over hundreds of miles. They fit over 42 mm-wide tires with 62 mm-wide fenders, or 54 mm-wide tires without fenders. They are designed to work with cantilever posts that are spaced between 62 and 84 mm wide. To work with the ultralight design of these brakes, the height of your frame’s cantilever posts must be within standard tolerances. (Your current brake’s pads should be roughly in the middle of the slots.) If the pads of your current brakes are at the top or bottom of the slots, the René Herse brakes may not fit on your frame.
We are excited that we now can use these amazing brakes on many of our own bikes. For more information about the René Herse brakes or to order a set, click here. And if you’re curious about René Herse himself, we recommend our book on the ‘magician of Levallois.’

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Compass Centerpull Brakes for Bolt-On Mounting

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We now offer Compass centerpull brakes with a backing plate for bolt-on mounting, in limited quantities. Many customers have asked for this: Wouldn’t it be nice to get the superlight weight and superior performance of these brakes on an existing bike?
A backing plate connects the pivots with the fork crown, which makes it possible to bolt these brakes onto any bike with brake-mounting holes in the fork crown and in the rear seatstay bridge. You’d get much better performance than most other long-reach brakes, which often suffer from excessive flex and offer only poor braking performance.
For us, the problem was cost: A backing plate requires a new forging die, which is very expensive. We would have to sell hundreds of bolt-on brakes to amortize this cost. We could CNC-machine the plate, but then it would have to be much larger to offer the same strength, negating the light weight and elegance of the forged Compass brake arms. What to do?
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At this point, I was reminded of Preston Tucker, who introduced his revolutionary “Torpedo” in 1948 (above). Unable to get his new torque converter transmission ready in time for the car’s launch, Tucker’s engineers realized that transmissions from old Cords could be used in the new Tucker. So Tucker’s team scoured scrapyards to recover these transmissions, which were rebuilt with strengthened parts and installed in the first Tuckers.
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I realized that the backing plates we needed also were lying around in parts boxes and junk bins: They had come off old Mafac Raids when builders used those brakes with brazed-on pivots. In fact, I had a set myself, left over from building my René Herse way back before Compass brakes were available. The backing plates don’t wear out – any play in the bushings comes from wear of the aluminum arms, not the steel pivots – so the old Mafac backing plates remain as good as new. We found a number of these, and had them refurbished and polished by our friends at Norther Cycles in Portland.
Now we are offering the Compass centerpull brakes with backing plates. The brakes are sold individually, with all the hardware needed for bolt-on mounting. If your frame has recessed brake holes, you can either use the supplied bolt and nut, or you can modify the bolts and use recessed nuts.
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Of course, the backing plates add some weight and flex, so they’re not the ultimate solution. If you are thinking about repainting your frame anyhow, just have a framebuilder add the braze-ons and use our standard centerpulls. That is what Steve Frey did on his “hot-rodded” Trek (above), which we featured in the Winter 2016 Bicycle Quarterly. Or add braze-ons to the fork (as well as rack-mounting eyelets) and use a bolt-on brake on the rear, where you don’t need that much braking power.
Quantities of the bolt-on centerpulls are limited by our supply of backing plates. And if you have a spare set of Mafac Raid backing plates (distance between pivots: 75 mm), or a spare set of bolts and hardware for bolting the backing plates onto the frame/fork (all models), please get in touch. Like Preston Tucker, we are paying good money for what otherwise would be useless parts.
Click here for more information about Compass centerpull brakes.

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Disc Brake Pros and Cons

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Disc brakes have become increasingly popular on bicycles in recent years, especially on “Allroad” bikes with wide tires. Bicycle Quarterly has tested more than 20 bikes with disc brakes. Our challenging adventures have provided excellent opportunities to learn about the advantages and disadvantages of modern “Road” disc brakes.
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I remember enjoying the excellent power and modulation of the then-new SRAM Red hydraulic discs on the descent from Naches Pass, but the caliper flexed the fork blade so much that the front wheel turned right each time I braked hard. At the other end of the spectrum, I sailed through a red light on a steep Seattle street, because an early mechanical “road” disc simply lacked the power to stop the bike.
What you’ll read here is a more detailed and differentiated view than the usual “discs offer great stopping power” generalizations. As with many things, disc brakes have advantages and disadvantages. Whether they are right for you (and which ones to choose) depends on how you ride.
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Experts like to point out that rim brakes are in fact disc brakes – the bicycle’s rim acts as the disc rotor (above). That is true in a technical sense, but it also points out the main differences between the two types of brakes.
On rim brakes:

  • Good: The “rotor” – the rim – is very large (close to 600 mm on most road bikes). With such a long lever arm, the brake caliper does not need to squeeze the rim extremely hard to stop the bike.
  • Bad: The brake caliper must reach around the tire. This means that brakes for wider tires are heavier and more flexible than those for narrow tires.

On a disc brake, the opposite is the case:

  • Bad: A disc brake’s separate rotor is much smaller (140 – 200 mm on most bikes). The caliper must squeeze the rotor very, very hard to slow the bike.
  • Good: A disc brake caliper only has to reach around a very thin rotor. Thanks to the caliper’s small size, flex is not an issue.

The advantages of disc brakes are most pronounced on bikes with wide tires. That is why disc brakes are so popular for Allroad bikes: Most rim brakes for wide tires offer sub-par performance. Here is why:
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Scaling up the dual-pivot brake of a racing bike may provide clearance for 35 mm tires, but it results in a heavy and flexible brake. See the long lower arm of the brake in the photo above? When you brake hard, it will flex significantly.
Such a brake may feel fine during moderate braking, but pulling harder on the brake lever only flexes the brake, without increasing brake power on the rim. That is a problem during emergency stops. It’s an even bigger issue during wet rides, when you need extra braking power to squeeze the water off the rim. Anybody who has descended a mountain pass in the rain and squeezed the brake lever as hard as they could without being able to stop is going to look for a better solution.
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The problems of rim brakes can be solved by moving the pivots closer to the rim. This reduces the flex, since only the part between the pivot and the brake pad flexes significantly. (It’s the part that gets twisted as the brake pads are pulled along with the rim.)
Cantilever brakes (above) locate the pivot close to the rim. That makes them very stiff. The problem is that the stiff brake is attached to the flexible fork blades or seatstays, which twist when you brake very hard. This changes the toe-in of the brake pads and results in poor modulation.
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Centerpull brakes (above) have pivots near the fork crown or brake bridge, so flex is less of an issue. That is why they generally offer better modulation than cantilevers. The best models also have very stiff arms, and almost no brake lever travel is wasted to brake flex.
Placing the pivots next to the rims is such a logical solution that it’s now used on racing bikes, too: the latest “Direct Mount” brakes use the same geometry. The only difference: The arms are actuated by a linkage (which adds weighs and friction, but eliminates the need for a straddle cable).
Really good rim brakes for wide tires exist, but they aren’t very common. This may be one reason why disc brakes have taken over. They are better than “average” rim brakes.
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How do disc brakes compare to rim brakes?
The advantages of disc brakes are easy to understand:

  • Power independent of tire size: Brake design (and power) are not constrained by tire size. You can use the same brake for any tire, and you get as much brake power with wide tires as you do with narrow ones.
  • Wet-weather performance: Because the rotor is small, the caliper must squeeze the rotor much harder than it does on a rim brake. This means that water will be scraped off the rotor quickly when riding in the rain. The best rim brakes also have enough power to offer decent wet-weather performance, but with disc brakes, even relatively inexpensive models work fine in the rain.
  • Separating tire and brake eliminates the risk of cutting into the tire with maladjusted brake pads. There is no risk of overheating the tire during long mountain descents. It also keeps rim and tire cleaner.
  • Switch wheels sizes on the same bike. For example, I could ride my Firefly (photo at the top) with superwide 26″ tires on rough gravel, with moderately wide 650B wheels on rough roads, and with skinny 700C tires on super-smooth roads. The outer diameter of all three wheelsets would be the same, and where the rim is located doesn’t matter with disc brakes. (In practice, this isn’t really an advantage, since the latest research by Bicycle Quarterly shows that wide tires roll as fast as narrow ones even on smooth roads.)

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As so often, the same features that are responsible for the advantages of disc brakes also can be disadvantages:

  • Mechanical disc brakes often are not very powerful, because their rotors are so small. With 160 mm rotors, mechanical disc brakes don’t stop you as well as good centerpull (or racing dual pivot) brakes. This problem can be solved with bigger rotors. Stay away from “road” bikes with tiny 140 mm rotors. They are simply too small for optimum braking on pavement.
  • Hydraulic disc brakes offer plenty of power, but their hydraulic lines tend to be fragile. On one test bike, we had a brake line blow out after it got kinked slightly during shipping. Fortunately, this didn’t happen on the road, but in the workshop while adjusting the brakes.
  • Grabby: The most powerful disc brakes can suddenly lock onto the rotor. Especially at low speeds, braking power is hard to modulate. This isn’t a huge deal, but it shows that disc brake technology is still evolving.
  • Pad rub: Disc brakes must be very close to the rotor – this is the flip side of the high mechanical advantage that scrapes off the water so effectively in the rain. If the rotor is slightly out of true, it will rub on the pads and make annoying squeaking sounds.

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  • Pad wear: Disc brake pads are relatively thin, and they wear out much faster than rim brake pads. On long, wet rides, you can run out of brakes completely, so carry spare pads! Fortunately, pad replacement is easy on most models.
  • Weight: Many bikes with disc brakes are heavier than their rim brake counterparts, but this needn’t be the case. Yes, the extra rotor and heavy caliper add significant weight, but much of that weight can be saved again on the rim, which doesn’t need a brake track, nor extra material to accommodate wear. With high-end carbon rims, a disc brake bike will weigh almost the same as with a good rim brake setup. The down side is the high price of carbon rims.
  • Stiff fork blades: Disc brakes require relatively stiff fork blades, because the caliper is mounted near the bottom of the fork. This means that the small-diameter, shock-absorbing fork blades of our favorite custom bikes don’t work well with disc brakes. For production bikes, this isn’t really an issue. Most production forks don’t offer much shock absorption anyhow: They are plenty stiff for disc brakes.

In a single sentence, the conclusion may be as follows: Even mid-range disc brakes offer adequate performance. The best rim brakes also offer plenty of power, but cheaper models for wide tires do not offer good braking, especially in the rain.
For a custom Allroad bike, where I can choose the best brakes and design the bike around them, I still prefer rim brakes. The best centerpulls (with brazed-on pivots) offer a sweet modulation that discs cannot yet match. Their pads last much longer. And they can be used with the flexible fork blades that increase comfort and speed, especially on rough roads. Just watch your pads to make sure they don’t cut into the tire. And be prepared to get muddy legs during long, rainy mountain descents (below).
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But if you are looking for a production bike, centerpulls with brazed-on pivots aren’t really an option – too few bikes come equipped that way. Cantilevers offer fine stopping power, but especially with carbon forks, you often get fork judder. Disc brakes often are the best option for these bikes. Choose good brakes, maintain them well, and they won’t detract from the enjoyment of your bike. Here is what to look for in disc brakes:

  • For the ultimate in stopping power, get hydraulic calipers.
  • The best mechanical discs are fine for most riding. We’ve had good experiences with the TRP Spyre. Make sure your front rotor is no smaller than 160 mm. I’d prefer 180 mm (200 mm tends to be too grabby at low speeds), but few bikes come equipped that way.
  • Check your pad wear regularly. On long rides, carry spare pads.
  • Be prepared for the occasional squealing as your pads rub. On most mechanical brakes, centering the pads is easy with a 3 mm Allen wrench.

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Further reading:

Photo credits: Natsuko Hirose (photos 1, 10, 11); Duncan Smith (6, 7); Hahn Rossman (2, 8).

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A Photo Says More than 1000 Words

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This photo shows our Compass centerpull brake with the straddle cable released. (It also shows a Rinko fender, and a Babyshoe Pass Extralight tire after about 5000 kilometers…) More than a thousand words, this photo explains the design of our brakes:

  • The arms fit around 42 mm-wide tires and fenders with generous clearances.
  • You can install the wheel with its 42 mm tire inflated. (Most other brakes for wide tires require deflating the tire every time you remove the wheel.)
  • The brake is dimensioned so the pads are about 2/3 of the way down – not at the limit. This gives you some room for adjustments.
  • When the pads wear, it’s easy to slide them a bit further inward, without having to completely re-adjust the brake.

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With the straddle cable closed, you can see how nicely the arms are profiled to fit over the fender. It’s a small detail, but it makes the bike so much more beautiful. (It’s also one of the reasons why the brake opens so wide.)
The slender arms don’t just look nice, but they also make this one of the lightest brakes on the market – lighter than Dura-Ace racing brakes. We used Finite Element Analysis to optimize the brakes’ stiffness, so they offer excellent braking power and superb modulation. And the arms are forged, not CNC-machined, so they are plenty strong despite their superlight weight.
Fender clearances are an important topic for “real-world” bicycles. The photos show 20 mm clearance between frame and tire. That is more than you find on most “fender-ready” bikes today. But there is a good reason for this: With that much clearance, the fender won’t rub even if a fender stay gets bent. More importantly, small debris will clear the fender rather than risk getting stuck and cause the fender to collapse and jam against the frame.
rando_bar_touring
Of course, you don’t want so much fender clearance that the bike has that “Motocross” look, but my “Mule”, the bike you see in the photos here, is far from that. A bike with well-judged fender clearances looks graceful, yet it’s supremely functional.
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Our brakes come with detailed instructions on how to get all these clearances right. The Compass brakes are part of a system: They work perfectly with our superlight CP-1 rack. Our centerpull braze-ons are pre-mitered to fit Kaisei “Toei Special” fork blades. Of course, you can also use other components, but this system makes it easier to build a bike that is both beautiful and functional.
Compass_brake_rear_bike
Beauty, light weight, performance and superior function in every way – that is what we strive for with every Compass part we design.
Click here for more information about our brakes.

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Compass Racks: Light Mount Optional

rice-field
We love handlebar bags. They are easy to access, they don’t affect the bike’s handling when you ride out of the saddle, and they are more aerodynamic than rear bags. (Yes, we did test that in the wind tunnel!)
To take a photo, you stop, put a foot down and get out your camera. Less than 30 seconds later, you are back on the bike. This means that you take more photos and bring home more memories. The map pocket on top allows you to view your route sheet at all times, so you are less likely to get lost. Or if you don’t need a route sheet, you can use the pocket for a photo of a loved one.
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To carry a handlebar bag well, you need a front rack. Otherwise, the bag sits too high and affects the handling of your bike. Supporting the bag from below not only is stronger, but also lighter. (Yes, we’ve weighed many bags to check this.) Supported by the rack, the bag doesn’t have to be sturdy and stiff, which saves more weight than the rack and decaleur add. Speaking of racks, Compass offers two racks for handlebar bags.
mule_rack_2
The CP-1 rack is designed for our Compass centerpull brakes. It’s superlight – just 168 g – yet super-strong and elegant. It’s the perfect solution for a custom bike: You get great brakes and a great rack that are designed to work together.
m13_lightmount_angle
For bikes with cantilever brakes, we offer the M-13 racks. These racks attach to the canti posts and the fork crown, so they fit many bikes. We offer two versions: The “wide” version is intended for bikes with wide tires, which have more space between the fork crown and the cantilever braze-ons. The “narrow” version works on bikes with tighter clearances.
We’ve added new models to our rack line-up, so that you can get most racks with a choice of light mount (above) or with simple eyelets that give you the choice of using a light or not (top).
Our latest racks are made by Nitto to our exclusive “Extralight” specifications from lightweight, yet ultra-strong, Cromoly tubing. Our “Standard” racks use the same materials as Nitto’s other racks. Even the standard version gets nicer workmanship and a better finish than Nitto’s “production” models.
The beautiful finish is matched by careful design. For example, our dedicated light mounts went through many prototypes until we worked out a location that places the light in just the right spot – protected if the bike falls over, yet far enough forward so that your front tire doesn’t cast a shadow in your path when you make tight turns at night.
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All these details are things you’ll appreciate when you ride at night, whether it’s on your commute or during a randonneur ride that descends mountain switchbacks in the middle of the night.
Click here for more information about Compass racks.

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René Herse Rear Cable Hanger

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Compass Cycles is re-introducing the René Herse rear cable hanger. I have loved these simple, lightweight, elegant cable hangers – so much that I made my own when I built my Mule. There are many ways to design a rear cable stop for centerpull and cantilever brakes – this is the one I like best.
The hanger is held by the seatpost binder bolt – just make sure your slot is at least 2.5 mm thick. This is a much better solution than a cable hanger that uses a seatstay bridge (or even worse, a single post): Since the René Herse hanger is loaded in tension rather than torsion, it can be lighter, and yet it will flex less. That results in a more positive braking action, removing some of the springiness that you often feel in rear brakes.
There are other cable hangers that attach to the seatpost binder, but none are as small and light as the Compass René Herse model, which weighs just 3 grams.
de-insulated
The secret is simple: Instead of making the hanger large enough to hold the cable housing and a superfluous ferrule, the Compass René Herse hanger is sized to fit the housing without the plastic covering. Stripping the plastic covering (and deleting the extra ferrule) gives you a metal-on-metal connection that also reduces the flex between housing and hanger – again improving the braking action. It’s not rocket science, but it’s a better, more elegant way of doing this. Of course, to make the René Herse rear cable hangers requires custom-machined parts, which are more expensive than standard ferrules.
Cable_hanger
The Compass René Herse rear cable hanger is made by Nitto to our specifications. Hand-brazed from steel, it’s polished to a mirror shine and then chrome-plated for durability and beauty. It’s equipped with a slot to make removing the brake cable easy – useful for Rinko and travel bikes.
cable stop_on_frame
To match the minimalist cable hanger, we also offer cable stop braze-ons in the same size. I’ve often been bothered by the huge cable stops used on most modern bikes – they seem almost as large as the top tube! Even though I intended my Mule to be just a “working bike”, I couldn’t bring myself to using those oversized stops. Instead, I made my own, smaller stops by cutting down derailleur cable stops.
housing_stops
I won’t need to do this in the future, as we now offer these stops. Of course, you can use the René Herse rear cable hanger on many bikes, but if you build a new frame, these braze-ons result in a more elegant, lighter and more functional setup. More functional? Less flex because there is no ferrule and no outer lining of the housing.
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At the front, where the brake cable housing turns with the handlebars, we recommend using a guide (arrow) to prevent the housing from getting kinked at the exit of the stop. This is a good idea no matter what type of cable stop you use. It’s just a short piece of tubing. On this bike, it’s been slotted to allow removing the brake cables when the bike is disassembled for Rinko.
Click here for more info on the René Herse cable hangers and housing stops.
The René Herse® name, logo and designs are registered trademarks of Compass Cycles.

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A Better Way to Adjust Toe-In

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Compass centerpull brakes now come with special washers to adjust toe-in. These washers are easy to retrofit on older Compass and even classic Mafac brakes. With this system, you to adjust toe-in only once, when you initially set up the brakes, and then never worry about it again.
toe-in
What is toe-in? It means setting up the brake pads so that the fronts are closer to the rim than the rears. This is important for cantilever brakes, because the fork blades twist when you brake, and the brake pads rotate in relation to the rim. With the right amount of toe-in, the pads will be parallel to the rim when you brake hard.
How much toe-in do you need? There are no firm values because it depends on how much your fork blades twist. It’s trial-and-error. Too much toe-in just makes your brakes work less effectively. Toe-out is worse: Your brakes don’t work well and they howl and squeal. When in doubt, go for a little toe-in rather than too little.
compass_brake_rear
Centerpull brakes attach close to the fork crown, so the fork blades don’t twist significantly. This is why centerpull brakes offer such consistent brake modulation. It’s also the reason they don’t require toe-in. Centerpull brakes work best when the pads are parallel to the rim at all times.
When we introduced the Compass centerpull brakes, the toe-in was not adjustable. In our testing of prototypes, we found that the brakes might squeal for the first few rides, but they became quiet as the pads wore until they were parallel to the rim. Most of our customers have had similar experiences. Riding in the rain helps, because it wears your pads faster.
However, we’ve found since that for a few riders, our brakes squealed, and continued to squeal longer than was acceptable. If the brake pivots on the frame and fork are brazed on at a slight angle, it’s possible that your pads initially have significant toe-out. Rather than wait for the pads to wear away, you’d want to compensate for the misalignment of the post by adjusting the toe-in.
We experimented with numerous ways to adjust toe-in, from the Shimano system of the late 1980s with its wedge-shaped washers to the modern spherical washers. We found all of them hard to adjust, hard to keep adjusted, and they all make changing brake pads a big pain. Basically, you have to hold the adjustment of the brake pad in three directions while you tighten the bolt:

  • angle of pad to rim (seen from the front)
  • alignment of pad to rim (see from the side)
  • toe-in (seen from above)

As you tighten the mounting bolt, all these alignments tend to move. You never get it right, and after a while, you just give up and accept whatever you have as “good enough”. Every Bicycle Quarterly test bike with cantilevers, even those set up by the best pro shops, has had inconsistent brake pad alignment.
What is silly about this process is that, at least on centerpull brakes, the toe-in should be set only once. It compensates for slight misalignment of the brake pivots, and those will remain the same for the life of the bike. Why would you design a system that requires riders to adjust the toe-in again and again, every time they adjust the brake pads? Wouldn’t it be nice if you could adjust the toe-in once, and then it have it remain the same forever? Adjusting and replacing brake pads would be easy!
toe_in_washer
So we adopted a system that does just that. It’s really simple: The washer that goes under the posts of the brake pad has one groove that is deeper than the other. This puts the brake pad at a 2.5° angle, which gives you about 2 mm of toe-in. There is a dot on the reverse (invisible once installed) that shows which groove is deeper. Install the washer in the orientation that you want your toe-in, and you are done. The washer remains in place as you adjust or change the brake pads, so you never have to think about it again. Your toe-in always remains the same.
And setting the adjustment is easy – you just substitute the new washer and then set up the brake as usual. Since the toe-in is pre-selected, you’ll get it right every time. With our post-style pads, tightening the mounting nut only tends to rotate the pads in one direction (alignment of pad to rim), which is easy to compensate. The other movements aren’t affected as you tighten the bolt, which makes it easy to adjust the brake pads. While we offer a special tool to hold the brake pad during this adjustment, it’s not really needed. Usually, I don’t bother with it.
Worried about adjusting your toe-in in smaller increments than 2.5°? As the pads wear, they’ll take care of any small differences. Realistically, if you get within a degree or two of your target value with modern spherical pads, you are doing very well.
Compass_brake_rear_bike
The new washers are included with all Compass centerpull brakes (in addition to the washers without toe-in for bikes with perfectly placed pivots). They also are available as a retrofit for Compass and classic Mafac brakes.
Unfortunately, this method for adjusting toe-in won’t work on most modern brakes, which use “bolt-on” rather than “post-style” pads. For those, somebody should design a system where you adjust the toe-in once and for all, rather than having to fiddle with it every time you adjust the brake pads. (Some cartridge brake pads allow you to replace the pads without disturbing the holders. Unfortunately, this doesn’t help when you have to adjust the pads as they wear, so they still hit the rim in the right place.)
One more piece of news about our brakes: They now are sold individually, to give you a maximum of flexibility when spec’ing your bike.
Click here to learn more about our brakes or to order your set of washers.

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Straddle Cables Done Right

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Straddle cables provide a light and elegant way of transferring the brake force: Every cable-actuated rim brake needs to transmit the force of the single brake cable onto two brake pads that squeeze the rim.
In recent years, straddle cables been replaced by direct-action V-brakes or complex linkages (on modern Shimano sidepull brakes). There are reasons for this: Current practice for straddle cables is less than optimal. However, these flaws can be eliminated with good design, resulting in brakes that are lighter and more powerful than the alternatives.
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Above is a typical straddle cable arrangement. The straddle cable is as thick as the brake cable, and that makes it very springy. You can see how it bends around the cable hanger in a gentle arc. When you apply the brake, you first have to straighten the straddle cable. This is lost motion – you pull on the brake lever, but you don’t get any brake power yet. If there is too much “lost motion”, you risk bottoming out your brake levers against the handlebars. To prevent this, you have to set your brake pads very close to the rims. Experienced mechanics “pre-bend” the straddle cable, so it better conforms to the cable hanger, but it’s always going to have some of that springiness.
Why is the straddle cable so thick and springy? It carries only roughly half the load of the brake cable, so it needs to be only half as strong. A thinner cable is less springy and conforms much better to the bend of the cable hanger. The top photo shows our Compass brakes, which use a thin shifter cable as the straddle cable. You can see how straight the cable runs. When you squeeze the brake lever, there is no lost motion.
There is a reason to use a thicker straddle cable: to prevent it from fraying where it clamps to the brake arms. The angle of the cable changes here as you apply the brakes: The cable becomes more vertical as the hanger moves upward and the brake arms move inward.
If the cable is clamped firmly to the brake arms, you bend the cable every time you brake, which eventually may cause it to fray. The angle change is more severe on centerpull brakes than on cantilevers. And when the cable frays, it’s only a matter of time until it breaks, and then you lose all brake power.
Compass_brake_swivel2
There is a better solution to this problem: cable attachments that swivel. Then the changes in angle don’t bend and stress the cable at all. You can use a thin straddle cable, which doesn’t “spring”, and you’ve eliminated all the disadvantages of straddle cables, while keeping their advantages.
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With optimized straddle cables, our Compass brakes work effectively the same way as Shimano’s latest racing sidepulls – the two pivots are next to the tire, and the lower arms are short to offer great braking power. Yet the Compass brakes use straddle cables instead of complex linkages, so they are much lighter than Shimano’s racing brakes, and they have less friction. When you use them on the road, you can feel the difference.
Click here to find out more about Compass brakes.
Photo credit (PBP photo): Maindru, used with permission.
 

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Centerpull Brake Parts and Tools

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For our Compass centerpull brakes, we started with a design that had proven itself in decades of hard use: the Mafac Raid brakes. In fact, we had logged tens of thousands of miles on our own bikes with these brakes. We thought hard about how to improve them, but apart from a few minor tweaks, the Mafacs appear unimprovable. The one thing we could improve is the quality. The original Raids were budget parts – well-designed, but the finish and tolerances often were mediocre.
That means that the Compass brakes use old-style canti brake shoes, which have a few significant advantages.

  • The brake arm isn’t twisted to accommodate the bolt-on brake shoes. This makes it stiffer and lighter.
  • You can slide the brake shoe inward as the pads wear, so there is no need for barrel adjusters or other mechanisms to take up pad wear. Since you’ll reset the pad angle, there is less risk of the pad starting to cut into your tire as it wears and hits the rim higher up.
  • Adjusting the pad angle is easier, because you can grip the pad holder as you tighten the bolt.

ToolGbBtWr
Mafac used to make a nifty tool to hold the pad holder in place as you tighten the nut. Grand Bois has re-introduced this tool, and we have it in stock. It’s beautifully finished, but most of all, it makes working on centerpull brakes (whether Compass or Mafac) so much easier.
MafacComp
We made sure our hardware is interchangeable with the classic Mafac brakes, since we could not improve upon their design.
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So if you have a brakeset with sloppy bushings or rusty bolts, you can rejuventate them with our Replacement Hardware Kit. The arms themselves never wear out. Polish them up, and install the new hardware, and your brakes look and perform better than new.
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To remove and install the bushings in the brake arms, Compass offers a simple tool. Use a hammer and gently tap the old bushings out of the brake arms. Then use the same tool to tap in the new bushings.
The holes for the Mafac pivot bushings have somewhat loose tolerances, so we recommend reaming the holes in the brake arms to make sure that our bushings fit. You need a 10 H7 reamer (10 means 10 mm, H7 is the tolerance of the fit), which is available in good hardware stores.
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Kool-Stop offers replacement brakes pads for Mafac brakes. They come in the normal length (4-dot) or extra-long for tandems (5-dot). Kool-Stop offers them both in their excellent salmon-colored compound for superior wet-weather brakes, and in black for restorations. We use them on the Compass brakes, and also sell them separately.
brakRHbrro_800
For the straddle cable hanger, we could not resist using the lovely René Herse rollers. Apart from the domed nut that is a slightly taller shape (so it will not bottom out, unlike the originals), the René Herse straddle cable hanger is an exact replica of the original, which is great for restorations of classic René Herse bikes. Of course, they also work great on other bikes. You have the option of letting the roller turn, which automatically centers the brake every time you apply it. If your brake springs have uneven tension, you can reverse the screw that holds the roller so that it does not turn. Then you can set the straddle cable position where you want it, and it won’t change. It’s a smart design – once again, we could not improve upon it.
BrakCmRhStraddle
We also offer replacement straddle cables for some Mafac 2000 brakes. They also fit some “Competition” models, but the straddle cable hanger may be higher than before. Fortunately, with centerpull brakes, the mechanical advantage does not change significantly with straddle cable height. (These straddle cables do not work for brakes that require the ball-end straddle cables.)
The Compass brakes use a standard shifter cable as the straddle cable, so you won’t need to worry about spare parts availability.
Click here for information about these and other Compass brake parts.

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Which Hand for which Brake?

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One of the most confounding questions in cycling is this: Which hand should control which brake? In the U.S., the law requires that all bikes are sold with the left hand controlling the front brake, and the right hand the rear brake. It’s the same in France. In Italy and Great Britain, it’s the other way around.
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Many myths surround the reasons for these differences, but history is the most likely explanation: Early bikes had only a rear brake. In France, this usually was a rim brake. The early brakes were not very powerful, so you needed lots of hand power to stop the bike. Most people are right-handed, and it made sense to control the single brake with the right hand. In Italy and Britain, the single brake was a coaster brake, and there was no brake lever at all.
When front brakes were added to bikes sometime in the 20th century, this required adding a brake lever to the handlebars. In France, the right side was taken, so they mounted the extra lever on the left (above). In “coaster-brake countries,” the handlebars were still empty, so the brake lever for the front brake went on the right side (below). When racers started using rim brakes on both wheels, the extra brake lever (for the rear wheel) went on the left side.
Baines-mono
The U.S. copied French practice – probably because Schwinn was the only company importing performance bikes with hand brakes, and Schwinn was influenced by French bicycles.
Those are the historic reasons why some use “right – front” and others “left – front,” but this doesn’t answer the question: Which is better?
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Many reasons have been put forward for the “right hand – front brake” approach. Most motorcycles use that configuration, since the right hand operates the throttle, the left hand the clutch, which in turn means that the right side of the handlebars is the only place to put a brake lever.
Some cyclocross racers prefer the “right – front” setup, so they can brake on the rear with their left hand as they dismount. I am not so sure this makes sense – to get your bike fishtailing when you have only one hand on the bars seems like a really bad idea. You really should be done with braking by the time you release the bars and prepare to shoulder the bike. (European cyclocross professionals generally seem to follow their country’s practice, with French and Belgian racers using the “left – front” setup.)
Yet others point to the fact that most riders are right-handed, and the front brake is the most useful one, so using your stronger hand to operate it makes sense. Except that a good brake shouldn’t require huge amounts of hand power…
What about the advantages of the “left – front” way of setting up your brakes? One advantage in the U.S., where we ride on the right side of the road, is that you can come to a stop and hold on to a railing or post with your right hand, while your left hand still operates the front brake. Being right-handed, I also often use my right hand to shift, eat or take photos, so it’s nice to have my free hand ready to brake with the more important brake.
It seems that there are pros and cons for each setup, but none are so great that they persuasively make one setup better than the other. It really comes down to personal preference.
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On bikes with centerpull or cantilever brakes, it’s easy to switch the brake cables from one side to another. If you have traditional (non-aero) brake levers, you don’t even need to rewrap the handlebar tape (above).
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Most sidepull brakes are set up for “left hand – front brake,” even those made by Italian companies like Campagnolo and Gipiemme (above)… yet most Italian racers route the cables the opposite way. The bend of the front brake cable is a little tight (especially with aero brake levers), but it’s not a big deal.
Whatever you do, I recommend being consistent. During a panic stop, your instincts will take over, and if you are used to pulling on one lever, you’ll find that if the brakes are reversed, you are skidding the rear wheel without slowing down significantly. Several of my friends use the “right – front” approach, and when I ride their bikes, I constantly have to remind myself of the reversed brake levers – and hope that I won’t have to stop in a hurry.
BQ72_brake_special
This post is excerpted from Bicycle Quarterly‘s “Brake Special” (BQ 26; above).
Photo credits: Hilary Stone (Baines Flying Gate), Gipiemme (Giovanni Battaglin).

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Compass Centerpull Brake Specs

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The new Compass centerpull brakes have been very well received. Numerous builders have asked for the complete specifications for the brakes, since many riders plan to use them on their new bikes. We sold so many of the centerpull braze-ons that we are currently out of stock of these pivots, but another shipment is expected next week.
We recommend that builder have the brakes on hand when they build the bike, so that they can make sure everything fits just right. We have the specifications available online as part of the instructions for the brakes. This also allows riders to check whether the brakes will fit their existing bikes.
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The specifications include detailed drawings that allow builders to get the clearances just right for bikes with 650B x 42 mm tires and full fenders. These measurements are the result of a year’s work: measurements were taken, calculations performed, CAD drawings created, prototypes built… We wanted the entire system of fork/tire/fender/brake/rack to be right, once and for all. These specs will be useful for builders who are not using Compass brakes on their current project, since they show the optimized clearances for tires and fenders.
The Compass CP1 rack is specifically designed to go with the Compass brakes. (The rack only works with centerpull brakes.) The rack is based on a René Herse rack that combines elegance, light weight and rigidity.
It is important that the brake pivots are located at the right height, otherwise the rack will sit too high or too low above the fender. The instructions for the brakes include all measurements a builder needs to build a bike with our brakes and our rack.
The rack and brakes also work for other configurations in addition to 650B wheels and 42 mm tires. For other wheel diameters, the dimensions remain the same in relation to the top of the tire – the builders simply adjusts the measurements for the different outer diameter of the wheel.
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It’s been a lot of work to get to this point, but when we rode these brakes during pre-production testing (above), we realized that it was totally worth the effort. The absolute braking power of the Compass brake is great, and the modulation is superb. This gave us great confidence descending challenging mountain roads at speed. As always, the goal is to have more fun on our bikes!
Click here to download the complete instructions.
Click here for more information about the centerpull brakes.
 

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Compass Centerpull Brakes Are Here!

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We received the last parts for our centerpull brakes, test-assembled them, wrote the instructions, and now they are ready to ship.
Click here to read more about the advantage of centerpull brakes.
There are a lot of parts to a centerpull brake. It all starts with the braze-on posts that mounts onto the fork and seatstays. The holder for the spring is a ring that slides onto the post. It gets brazed in place when the builder brazes the posts onto the frame/fork. The builder can rotate the rings inward or outward to get more or less spring tension. (In practice, the standard setting, with the holes directly above the bosses, works great for most riders and with most brake levers.)
brakCmPiv_769
The posts are available in three models:

  • Front (top): mitered to fit the Kaisei “Toei Special” fork blades without any additional filing. Of course, they can be mitered to fit most other fork blades.
  • Rear (middle): with an offset miter that works well for most frame sizes.
  • Universal (bottom): un-mitered bosses for any situation where the pre-mitered bosses don’t fit.

The brake arms are forged for the ultimate in strength and light weight, instead of machined. We analyzed many different shapes, and found that the classic Mafac Raid model optimizes strength and weight, while providing the optimum leverage to work with a multitude of brake levers. So we started with that shape and subtly optimized it for the added grip of modern brake pads. (You can use classic brake levers as well as modern STI/Ergo/DoubleTap lever with these brakes.)
The springs are custom, too. We tested stainless steel springs, but found that their rate changed over time, so ours are chrome-plated spring steel. That way, your brakes will retain their consistent performance for decades.
We made custom brake pad holders, which are a bit shorter than most modern pads. This allows them to clear the fork and seatstays when you open the brake, so that even fully inflated 42 mm-wide tires can pass through. The pads are Kool-Stop’s salmon-colored pads. These old-style pads are thicker than modern ones, which means they’ll last a lot longer. Of course, they use the best modern compound for the ultimate in brake power, both in wet and dry conditions.
mafac_hardware
Even the bolts are custom-made. (The only off-the-shelf parts are the silver washers on the left and the straddle cables.) Using custom bolts not only allows us to have smaller (and lighter) bolts, but the brake arms themselves are smaller and lighter, too.
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The straddle cable attachment consists of four custom pieces. At one end (right in the photo above) there is the “dumbbell”, which acts as a quick release. (You unhook it from the brake arm to open the brake.)
On the other side (left), there is an eyebolt with a spacer and a special nut. The advantage of this system is that the two anchor points of the straddle wire can swivel as the straddle cable angle changes when you apply the brake. This eliminates the stress that tends to break straddle cables. It allows the use of a thinner shift lever cable as a straddle cable. The thinner cable can make a tighter bend at the cable hanger, so it doesn’t have as much springiness that translates into lost travel when you apply the brake.
Using a standard shifter cable as the straddle cable also means that if you ever need to replace the straddle cable, it’s easy to find a replacement. And you can set the straddle cable height where you want it – here it is set high so the hanger does not obstruct the taillight. (Centerpull brakes are not very sensitive to straddle cable length, unlike some cantilevers.)
Many will recognize these design features from classic Mafac centerpull brakes. We tried to improve on them, but with a few exceptions, we couldn’t – those mid-century French engineers knew what they were doing! Using tried-and-true technology not only means that we don’t need to worry about parts breaking, but also that our hardware fits on classic Mafac brakes.
If you have an old Mafac brakeset, you can use the new Compass hardware to replace everything but the arms, which shouldn’t wear out… If you want a brake for narrower 700C tires, a set of Mafac “Racer” arms and our hardware will get you a brake that is as good as new.
brakRHbrro_800
We didn’t like the stamped aluminum Mafac straddle cable hangers, so our brakes instead come with a replica of the lovely René Herse straddle cable hangers. These are reversible, so you can either set them that the roller spins freely, and equalizes the brake force of the two arms, or, if you have problems with one pad rubbing, you can set it so that the roller is fixed.
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Together with the brakes, we offer a rack that is custom-designed to offer the same clearance as the brake. The rack is patterned after those made by René Herse. It is a clever piece of design that eliminates most of the stress risers where racks can break. Made by Nitto to our specifications, it’s also very light and elegant. We added a light mount, so that modern headlights (Edelux, IQ Cyo, etc.) can be mounted directly.
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The rack attaches to the brake posts with special René Herse bolts, as well as to braze-ons on the fork. (Unfortunately, that means it isn’t an easy retrofit.)
We feel that by combining the genius and expertise of René Herse, Mafac and Nitto, we have created one of the very best brake/rack system for bikes with wide tires.
Click here for more information on the brakes, and here for information on the rack.
 
 

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Compass Centerpull Brakes

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When we started Compass Bicycles, we dreamed of a new centerpull brake. We started developing and testing right away, but it has taken a few years for that work is coming to fruition. We just received the first production samples! The new Compass brakes will be in stock in early November.
For a bike with wide tires, centerpull brakes with brazed-on pivots are the best brake option. With pivots on the fork blades, there is little flex compared to a sidepull (or dual pivot) brake that reaches all the way around the tire. And since the pivots are close to the fork crown, they don’t twist like those of cantilever brakes. As a result, centerpull brakes offer more brake power and better modulation than other rim brakes. (The fact that Shimano’s latest rim brakes also use pivots high up on the fork blades shows that we aren’t the only ones who have figured this out.)
Of all the centerpull brakes, the Mafac Raids stand out. Mafac designed them in the 1970s, when they had decades of experience with this type of brake. The relationship between the upper and lower arms is perfect, which means you get lots of brake power, yet the pads don’t have to be set very close to the rims to prevent the brake levers from bottoming out. The brakes work well both with modern aero levers and with traditional levers. (Their cable pull is right in the middle between sidepull and cantilevers.) We tried many other centerpull brakes, but none came close in performance and feel.
During the development of our brakes, we did finite element analyses of various centerpull brake arms. We found that they varied greatly in their stiffness. Once again, the Mafac Raid came out on top. So when it came to decide on the shape and general design of our brakes, we couldn’t improve on the Raids.
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We wanted a lightweight brake, so of course we forged the brake arms. Like the Mafac originals, our new brakes use custom hardware throughout – a huge project when you look at how many special bolts, nuts and washers there are on these brakes. (When you design a brake for standard screws that you can buy at hardware stores, you inevitably have to compromise weight and performance.) The hardware is made from chrome-plated steel, which is stronger than stainless steel.
We did improve a few things compared to the original Mafacs:

  • We made the arms slightly thicker, to make sure the brakes work with the higher brake forces generated by modern pad compounds. The weight gains are minimal.
  • The bushings of the original were cheap plastic and often developed play. Ours are special IGUS bearings that should last a long time.
  • The original pad holders were made from stamped aluminum, and the posts could come loose. Ours are cast as a single piece, with integrated posts.
  • The mounting bolts of the Mafacs, with their thin heads, also are known to fail when you aren’t careful during tightening. Ours are stronger, with integrated washers based on a René Herse design.
  • We improved the finish of the arms and the plating of the screws.
  • Our braze-on pivots don’t have the ugly aluminum plates to hold the spring. Instead, there is a ring with the spring hole that the builder brazes onto the post. (The photos still show the Mafac/Dia Compe braze-ons, since ours weren’t ready when the frame was built.)

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To go with the brake, we’ll also offer a small rack to support a handlebar bag. The rack is made in Japan from CrMo tubing, so it is very light, yet strong. It’s patterned after the racks René Herse made for his randonneur bikes. The rack requires braze-ons on the fork, so it’s not a retrofit. If you plan to get a new bike, these brakes and rack are a big step forward.
We’ve been testing prototypes for quite a while, and we are excited that the new brakes will be available soon. We’ll also offer the hardware separately, so you can make your old Mafacs as good as new with new bushings, new hardware and new pads.

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