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Archive | Myths in Cycling

Myth 19: 700C Wheels Are Faster

When we started this series to celebrate Bicycle Quarterly’s 15th anniversary, we thought we’d eventually run out of myths. But it seems that new ones are created as fast as we can debunk old ones. The latest is “700C wheels roll faster than 650B.”

This is stated with the same certitude as the old “narrow tires are faster” – and it’s just as wrong. Simply put, there is no evidence that 700C wheels roll faster than 650B (or 26″), and much data to show that they all roll at essentially the same speed.

In theory, it’s compelling to believe that a larger wheel will roll over road irregularities faster: The angle of attack is shallower, and the larger wheel will roll up onto the obstacle, rather than bump against it.

The reality is that the three most popular wheel sizes (above) are so close in size that the small differences are simply not important, even in an age of ‘marginal gains.’

Our testing confirms this: On smooth pavement, all three wheel sizes rolled at the same speed.

We ran otherwise identical 42 mm-wide tires (Schwalbe Marathon HS) at identical pressure. The only difference was the wheel size.

The dark gray area of each column shows the ‘confidence interval,’ which overlap for all tires. The small differences you see are noise in the data. (Ignore the fourth column: We ran one tire at different pressure to make sure small differences in tire pressure didn’t affect our results.)

What about rough roads and gravel? Above is the same test on highway rumble strips – pretty much the roughest ground you can find. (We chose rumble strips because they are uniform, not random like gravel or cobblestones.) Again, you see the confidence intervals overlap – the three wheel sizes roll at the same speed.

We’ve repeated these tests multiple times, with different methodologies (power meter, roll-down), always the same results: 700C wheels don’t roll faster than (slightly) smaller ones.

The real world confirms these results. Ted King has won Dirty Kanza on 650B and 700C tires, while most other racers were on 700C, because their sponsor’s bikes and wheels were designed for this tire size.

So where does this myth come from? Modern all-road bikes with disc brakes make it easy to swap wheels between 650B and 700C. Most riders use their 700C wheels on the road with fast-rolling racing tires. Their 650B wheels are shod with heavy gravel tires. And yes, the 650B wheels will be slower.

Of course, comparing supple and light 700C racing tires like the Vittoria Open Corsa CX or the Rene Herse Extralight with stiff and heavy 650B gravel tires like the Schwalbe G-One or the WTB Horizon makes little sense. The reason why the racing tires are faster isn’t the size of the wheels they are mounted on, it’s their supple casing. And if you made a 650B tires with the same supple casing, it would be just as fast. (We’ve done it and tested that, too.)

A 700C x 28 wheel has the same diameter as a 650B x 48 mm, so the angle of attack will be the same for both. This shows the absurdity of the argument. Of course, wheel makers want to tell you that you need two wheelsets, and tire makers would rather add a ‘fast-rolling 700C version’ to their lineup than develop a truly fast gravel tire.

Our OPEN U.P.P.E.R. test bike is gone now, but while I rode it, I knew that the 650B wheels (shod with our 48 mm Switchback Hill Extralights) weren’t holding me back. Nor was anything else – this was one of the fastest bikes I’ve ridden.

The U.P.P.E.R. also illustrates why 650B wheels make sense on all-road and gravel bikes: A 48 mm-wide 700C tire would require longer chainstays (adding weight and flex where you don’t want it), it would cause toe overlap, and it would take away from the nimble handling that made the OPEN so much fun.

Wouldn’t the U.P.P.E.R. be even faster with 700C x 28 mm tires? That question brings us full circle to the first part of this series: Myth 1: Wider Tires Are Slower.

Of course, Rene Herse offers all three popular tire sizes: 700C, 650B and 26″. That way, you can choose what works best for you.

Further reading:

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Myth 16: Higher Tire Pressure is Faster

This used to be one of the first things you learned as a cyclist: If you want to go fast, make sure your tires are pumped up to the maximum pressure. The harder your tires are inflated, the faster they roll.

We now know that this isn’t true. The realization that tire pressure does not affect performance is the key to the revolution that has swept through the cycling world in recent years. Without this new-found knowledge, all-road bikes and their supple, wide tires would make no sense at all. Here is how it works.

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Myth 15: Marginal Gains

‘Marginal gains’ are the latest buzzword in cycling. The idea is that many tiny improvements can add up to make a meaningful difference. Make 10 changes that each save 3 Watts, and you’ll have gained 30 Watts…

Think of Greg LeMond winning the 1989 Tour de France by eight seconds… If the second-placed rider, Laurent Fignon, had used ceramic bearings, he might have won that year.

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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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Myth 10: Stiffer Forks Steer Better

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 out not to be true. This week, we have a ‘double feature’ that looks at fork blades. In the first post, we looked at whether they flex enough to improve comfort. Here we examine the belief that stiffer fork blades make the bike steer better. Continue Reading →

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Myth 9: Fork Blades Don’t Flex

When we first started talking about shock absorption and fork blades, it was commonly believed that fork blades didn’t flex significantly. Experts told us: “All the flex in a fork is in the steerer tube, where the lever arm is longest.” And yet, when we rode bikes with flexible fork blades, they clearly took the edge of bumps. Was this another myth in need of debunking? Continue Reading →

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Myth 8: Modern Components are Lighter

To celebrate Bicycle Quarterly‘s 15th anniversary, we are looking at myths in cycling – things we all used to believe, but which we’ve since found out not to be true. During these 15 years we’ve learned a lot, and perhaps the most intriguing discovery is that modern parts aren’t as light as some classics. In some cases, there are functional reasons why modern parts are heavier. At other times, modern parts really could be lighter. Continue Reading →

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Myth 7: Tubeless Tires Roll Faster

When tubeless tires first became available, they were designed for mountain bikes and it was their resistance to pinch flats (above) that made them popular. Off-road, there are few nails or broken bottles that can cause punctures (and even those usually will be pushed into the soft ground rather than puncture the tire), but rims can bottom out on sharp rocks and other obstacles. So much so, in fact, that top mountain bike racers used to race on tubular tires – because tubular rims make pinch flats less likely. Eliminating tubes did the same, and while you still could ‘burp’ the tire, in general, tubeless allowed running lower pressures with fewer problems. Continue Reading →

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Myth 6: Tread Patterns Don’t Matter on the Road

To celebrate 15 years of Bicycle Quarterly, we are examining 12 myths in cycling – things that we (and most others) used to believe, but which we have found to be not true. Today, let’s look at tire tread.

“Bicycles don’t hydroplane,” declared some experts many years ago. “Hence, tire tread patterns don’t matter on the road.” The first part is true – even wide bicycle tires are too narrow to lose traction due to hydroplaning – but the conclusion assumes that tread pattern only serves to evacuate water from the tire/road interface. Continue Reading →

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Myth 3: Fenders Slow You Down

To celebrate 15 years of Bicycle Quarterly, we are looking at ‘12 Myths in Cycling’ – things that aren’t quite what we (and most other cyclists) used to believe. Part 3 of the series is about fenders.

Many cyclists here in Seattle install fenders when the rainy season starts, and remove them for the dry summer months. British time trialists even had quick-release fenders that they used on the ride to the start; then they took off the fenders for the actual competition. Our research indicates that this isn’t necessary – fenders don’t slow you down. Here is why: Continue Reading →

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Myth 2: Titanium is Lighter than Steel

In part 2 of our series ’12 Myths in Cycling,’ we’ll look at why titanium isn’t always lighter than steel. I can hear you saying, “What? Everybody knows that titanium has half the density of steel.”

That much is true: The same part made from titanium will weigh half as much as the equivalent from steel. But titanium has only half the stiffness, so the part will be half as stiff. To make the parts of the same stiffness, you need to use twice as much material with titanium, and the weight will be equal. The same applies to aluminum, which is one-third as heavy and one-third as stiff. (These numbers are for the high-strength alloys; raw aluminum, titanium and iron are not strong enough to be used for cycling applications.) Continue Reading →

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Myths in Cycling (1): Wider Tires Are Slower

When we started to publish Bicycle Quarterly 15 years ago, it seemed that most of the technical aspects of bicycles were well-established. And yet, as we tested many different bikes, we started to question many of the things we had accepted as ‘facts.’ To celebrate our 15th anniversary, we’ll look at some of these myths. We’ll explain why we (and everybody else) used to believe them, and how things really work. Let’s start this series with the biggest one:

Myth 1: Wider Tires Are Slower Continue Reading →

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