Super Tuck vs Aero Tuck

Super Tuck vs Aero Tuck

The big news in bike racing is that the UCI wants to ban the Super Tuck position. It’s a position pro racers sometimes use during fast descents, when reducing your wind resistance provides more benefit than pedaling hard. With the UCI decision, many cyclists wonder: How much benefit does the Super Tuck provide? And is there another way to get most of the advantage of the Super Tuck, without breaking the proposed rules?

On a bike, there are two ways to improve aerodynamics in a big way:
reduce the frontal area
reduce turbulence by closing the cavity under the rider’s chest.

When I was racing, older riders told me about the Aero Tuck (above demonstrated by Natsuko), which reduces the rider’s width by tucking the arms underneath the body. In recent years, the Super Tuck (below) has become popular. It reduces the rider’s height as they slide off the saddle and crouch on the top tube. Both close cavity under rider’s chest.

Everything else, even aero wheels, has a comparatively small effect. We measured the classic Aero Tuck (top photo) in the wind tunnel and found that it reduced the wind resistance by 32% over riding in the drops. Compare that to just 2-3% for aero wheels. No wonder tucking is so fast!

It’s likely that the Aero Tuck (top photo) is more effective on bikes with a relatively high bar position: You can’t get much lower by sliding off the saddle, so tucking in your arms and getting ultra-narrow results in the biggest reduction in frontal area. With a very low handlebar position, the Super Tuck (above) probably provides greater benefits.

To find out more about the Super Tuck in pro racing, I asked Ted King (leading in the photo above) about his experience.

  • Have you used the Super Tuck?

TK: Yes, for sure. This move became common during my time in the pro ranks, so it’s something I adopted, too. At Liquigas-Cannondale, I was teammates with Matej Mojoric (pictured above in the Bahrain Merida kit), who was already a young 2x world champion by the time he graduated to the World Tour. Matej perfected the pedaling Super Tuck and as the rumor went, that move helped him win at least one of those world titles. I remember being at a pre-season team camp and seeing him demonstrate his awkward, yet silky smooth, Pedaling Super Tuck as he flew out of sight. I was entertained by how odd it looked and how effective it was. I can’t say for sure that he introduced it to the World Tour, but Matej was doing it before cameras caught Froome zooming to victory in the 2016 with this move.

  • How effective have you found the Super Tuck?

TK: It’s extremely effective. While the Pedaling Super Tuck may be not a gracefully beautiful maneuver on the bike, I think that it’s efficacy is a big part of why we see it being used so often. That is, because it has both a significant and noticeable effect on speed.

  • Did you think it is dangerous?

TK: This is why the UCI wants to step in and ban it. The Super Tuck itself isn’t dangerous – you are locked into the bike, so it’s quite stable even when you hit bumps – but it has the potential to be dangerous if something dangerous is to happen. Namely, if something is to get in the way of a rider on a fast downhill, for example a car pulling out, or an animal jumping in the road, or a ball bouncing on course. There’s a fraction of a second lag for the rider to get themselves out of the tucked position – moving forward, then up, then back – and perform an evasive action or grab the brakes. Thankfully this hasn’t been an issue, but my assumption is that the UCI sees the potential for something going wrong, and they’re trying to proactively prevent an injury (or worse) down the road.

  • Do you think it should be banned?

TK: It seems a little funny to me to ban it. The slapshot in hockey was once banned, and the slam dunk in basketball was against the rules for ages, but these things — Super Tuck included — bring an exciting element to the sport. I guess for the time being I don’t think a hard and fast rule of banning it is the solution. I think with riders seeing how effective it is, there will be all kinds of ways that riders will bend the rules. Have you seen the superman, for example? That’s far more dangerous, but it’s not a Super Tuck, so is that still legal?!

  • Have you also used the more traditional aero tuck, with your bottom on the saddle and your hands next to the stem (making your profile narrower, rather than lower with the Super Tuck)? Moving your hands to the brakes is easier in that position, since you’re still sitting on the saddle...

TK: Yes, I’ve definitely used that trick. It’s certainly more effective than staying in the traditional riding positions. On a modern racing bike, it’s not as effective as the Pedaling Super Tuck. So maybe that’s the goldilocks that the UCI will allow — “aero enough, but not too aero!”

  • Thank you, Ted! It’ll be interesting how this all shakes out!

So how fast is the Aero Tuck in real terms? For our book ‘The All-Road Bike Revolution,’ I calculated a typical scenario based on the wind tunnel data: On a 6.5% hill, you have to pedal at 400 Watts to keep up with a rider who coasts in the Aero Tuck. Few riders can pedal that hard for long, and 6.5% isn’t even that steep. Any steeper, and there’s no hope of pedaling hard enough to make up for the lower wind resistance of the Aero Tuck. Plus, you’re resting in the Aero Tuck – albeit not very comfortably! – rather than pedaling hard.

You can confirm this easily on the road. Coast next to a friend who rolls at the same speed. Then get into the Aero Tuck, and you’ll just roll away.

That got me thinking about other ways to improve the aerodynamics. In the Aero Tuck, you sit on the saddle, so you can’t get any lower. And once your arms and legs are touching the top tube, you can’t get narrower, either. But you might be able to improve the airflow over the front of the bike with a small fairing. Surprisingly, a handlebar bag works that way. In the photo of Natsuko above, you can visualize how the bag directs the air around the ‘messy’ area between the rider’s arms and legs.

When I started using Strava, I was surprised that, on my familiar routes, I always reach higher speeds on the descents when I ride my randonneur bikes vs. racing bikes. The racing bikes are equipped with aero wheels, bladed spokes, etc., but compared to the handlebar bag, all these aero components seem to make little difference. I’ve found this to be true on multiple rides, several bikes, different descents. The bike setups (bar height, etc.) are similar, and since I’m in the Aero Tuck, even handlebar width shouldn’t matter. The higher speeds don’t correlate with wind direction or anything else, except whether the bike has a handlebar bag. And it’s significant – about 5 mph (8 km/h) on a 50 mph (80 km/h) descent.

Our wind tunnel tests have shown that the handlebar bag ‘fairing’ only provides an advantage when you get very low, but during a hilly ride like Paris-Brest-Paris, it’s the downhills where aerodynamics matter the most. And that’s where I can get in the Aero Tuck to get the benefit of both the more aero position and the bag’s fairing effect. To maximize this effect, we worked with Berthoud Cycles to make a ‘Rene Herse Special’ bag without side pockets. This reduces the width and turbulence of the bag and make it even more aerodynamic. (That’s the bag I use on my bikes.)

If you’re interested in how riding position, bike setup, clothing, bags, wide vs. narrow tires and drafting affects aerodynamics, check out our new book ‘The All-Road Bike Revolution.’ It looks at everything that makes a bike fast, comfortable and reliable, based on real-world testing, both in the lab and on the road.

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Comments (50)

  • Volsen

    What about dropper posts on fast bikes? All the tools.

    February 8, 2021 at 10:51 am
    • John Duval

      I would point at dropper posts as the future. It would solve the reaction time problem, and be much safer for armatures to emulate. The UCI weight limits cancel much of the extra weight. And it still takes advantage of the lower profile of modern race bikes. Swapping bikes would be easy. I believe neutral support is even adopting them. It is still relevant to amateur riders as they are growing ever more common. The sprinters probably would not use them due to the weight up high on the bike, but the super tuck is probably less important.

      February 8, 2021 at 1:44 pm
    • Ben

      I inadvertently discovered the super tuck as a teenager in the 90s. There was one particular hill where I would always try to best my previous top speed. Naturally my first inclination was to just pedal harder/faster. This worked to a point. One day I tried pedalling as hard as I could before the crest of the hill, and then leaning way over the handlebars and coasting on the actual descent. I gained several miles per hour!

      February 9, 2021 at 10:13 am
  • Timothy N

    In my eyes, and in my limited amateur experience, the vast majority of crashes in cycling come from drafting. The peloton is a hazardous place. But without it you simply vanish, or are winning the race. Will they ever ban drafting? Of course not, it’s part of cycling. So to is crouching about in various positions trying to gain advantage. This is silly. The lawyers must have taken over both the fax and coffee machines.

    February 8, 2021 at 10:59 am
    • Jan Heine

      Drafting is dangerous when you’re around riders whose reactions you can’t predict. When you’re with riders who ride like you, there’s little danger. Paris-Brest-Paris is always interesting: The first miles can be harrowing, because there are many crashes. After 36 hours on the road, I find myself riding in pacelines that are smooth and safe. Everybody should be tired, but what happens instead is that the riders have sorted themselves into groups of similar abilities and riding styles. This is even more pronounced with the BQ Team: We’ve ridden so much together that our brains work similarly. We don’t need to talk to anticipate what the others will do. We’ve ridden more than 30,000 miles as a group, and in all those miles, nobody has crashed due to overlapping wheels, etc. In fact, in all those miles, I recall only two falls – both when the surface suddenly changed to become much more slippery than before, as we entered a turn.

      Ted King tells me that in the pro peloton, riders take more risks because there is so much at stake. That, and not any dangers inherent in riding in close quarters, seems to be the cause for crashes in the pro peloton.

      February 8, 2021 at 12:38 pm
  • John C. Wilson

    Ted King looks pretty darn aero in the photo above. Natsuko looks fantastic.

    If the saddle can’t be lowered then lower the bottom bracket. In days of Campy 1037 pedals (wide pedals and tall pedals) bottom brackets were generally lower than currently. We all scraped up the pedals, ground them down to bearings. No one had problems. New pedals are tiny, should be possible to send the BB lower. At least on pavement.

    Sitting lower is good for aero, it is good for stability, it corners faster. Are you sure you can’t sit lower?

    Shorter cranks mean less motion in lower limbs, less air turbulence.

    When I was young (a very long time ago) we were taught how to ride. We were all taught to ride a straight line and to sit still in the saddle. No rocking allowed. Traveling down the road swaying from side to side and wandering all over the road is fantastically non-aero. On local roads it is just rare to see anyone sitting still in the saddle. When spotted they will most often be other old guys who shared the same teachers.

    February 8, 2021 at 11:13 am
    • Jan Heine

      That’s actually Ted’s former team-mate Matej Mojoric in the Super Tuck…

      Your idea of lowering the BB for aerodynamics – you won’t get much aero benefit, because you’ll lower the entire cyclist. It’s all about reducing the frontal area by keeping the feet in the same place and lowering (or narrowing) the rest of the body.

      February 8, 2021 at 11:22 am
      • Matej Goršič

        A benevolent correction and clarification: that’s actually Ted’s former team-mate(j) Matej MOHORIČ who is credited to have invented/brought the Super Tuck in pro peloton…

        February 9, 2021 at 10:23 pm
        • Jan Heine

          I’m sorry that’s not more clear. Ted mentions that the photo shows Matej…

          February 9, 2021 at 11:15 pm
  • CHARLES SHAND

    As a former racer and now a cyclo tourist, I’ve used both as appropriate. Personally I prefer the aero tuck as demonstrated by Natsuko, because I think that is inherently more stable than the Super Tuck. With the former, weight distribution is what I would describe as “normal” on the bike and shouldn’t mmake much difference to handling. However, with the Super Tuck you are shifting signficant weight over the front wheel and lightening the load at the back and on a lightweight racer I think this can induce “fishtailing” as the rear wheels hops over road bumps etc. Most of the downhill accidents I’ve seen watching the pro tours seem to start with a “fishhtail” and a large swerve around from the rear. With a Super Tuck, you’re less able to react to stabilise the bike, but in the aero position, you can react as usual, sit up quicker and apply your “air brakes” with yor body. That radical shift from Super to normal position can also create instability with the significant weight shifts. I can undertsand why the UCI has looked at this, particularly if they have done a more detailed analysis of downhill crashes. I can’t say for sure whether this would make a great deal of difference but I can see some logic in it. As a touring cyclist, let;’s face it, the Super Tuck is a bit OTT isn’t it ?? Hey, you’re out for bike ride, not trying to win the TdF, chill out, admire the scenery and enjoy yourself … !!!

    February 8, 2021 at 11:13 am
    • Dave Loyd

      Are dropper posts not allowed? I have noticed on my mtn bike on road descents that with the seat all the way down it’s more aero and more stable. Modern sloping top tube road frames should allow for a significant amount of drop. If people can pedal in the super tuck, they could do so with a low seat, without compromising bike handling to as great an extent.

      February 8, 2021 at 12:07 pm
    • Bern

      Yup to all this.

      February 9, 2021 at 5:35 am
  • Josh Greenfeld

    Love the info on the bar bag as an aero adaptation. I’m wondering if the top of the bag has to be flat to create an aero advantage or will a rounded top, like a typical “burrito” bag, also be more efficient than a no bag scenario? Thanks!

    February 8, 2021 at 11:17 am
  • David May

    A windscreen could reduce drag at all speeds, and keep the rider warmer in chilly conditions. Works great on a motorcycle.

    February 8, 2021 at 11:32 am
    • Jan Heine

      There used to be the Zipper fairing. The problem with all fairings is that they need to be very close to the rider’s body, otherwise, they just increase drag. Basically, they become just another shape you’re pushing through the air.

      That’s why the ‘Honda Goldwing’-type fairings are slowing those bikes down – they’re for comfort, not speed. To get a reduction in drag, you need a fairing like a Moto GP bike, which reaches within inches of the rider’s head. That’s why the Aero Tuck and Super Tuck are so effective – they close all those gaps that cause turbulence.

      February 8, 2021 at 12:13 pm
      • Dennis Ketterling

        The Zzipper fairings are still available!
        Problem? They attach the large “sail” to your handlebars (unlike a motorcycle), and from anecdotal info, handling in a crosswind was a saddle-clencher.

        February 8, 2021 at 2:38 pm
        • Jan Heine

          Frank Berto had one – I never asked him how it handled.

          February 8, 2021 at 5:49 pm
  • The Coasting Frenchman

    Hi Jan, and thank you for yet another informative article!
    In my own limited experience as a Sunday morning rider and chicken descender, using the aero tuck requires confidence in the bike’s handling and your own ability to get your hands back into the drops to grab the brakes. I also found it feels safer on high trail bikes that make you feel like you are riding “on rails”, or on a sort of “magic carpet” that is taking you to your destination, and that with non-aero brake levers, you get the cable housings in your nose!

    February 8, 2021 at 11:56 am
    • Jan Heine

      I find that the aero tuck is not well-suited to high-trail bikes, because they get thrown off course more by crosswind gusts. Apart from crosswinds, all bikes are very stable at very high speeds, since the rotational inertia of the wheels is getting so large that it’s more important than trail, wheel flop and all those other factors. Crosswinds are a different matter, because at high speeds, you move so fast that there’s a lot of distance (and hence veering off course) before you can react.

      February 8, 2021 at 12:16 pm
  • Gran

    They should ban the super tuck and un-ban dropper posts simultaneously. The largest benefit of the super tuck is getting your butt lower

    February 8, 2021 at 12:17 pm
  • kais

    once you put a dropper seat post on your bike, you may with aero tuck most likely get the same aerodynamic benefit as with the super tuck, but without its danger and maybe more important; without its ridicule:)

    my personal view is that super tuck is disrespectful to the sport, and best forgotten.

    an alternative if you dont use drop bars to reach a level back; is a backpack low on your back or even bum. i commute that way on a daily basis and it is quite efficent.

    February 8, 2021 at 12:34 pm
  • Owen

    I love the aero tuck but struggle to hold the position on long descents–I have some lingering issues relating to back and neck flexibility. Does anyone have any tips for stretches and/or exercises that might help mitigate this?

    February 8, 2021 at 12:54 pm
    • Jan Heine

      It’s never very comfortable to coast while leaning forward – without the pedaling forces, there’s nothing to keep your upper body in balance.

      February 8, 2021 at 1:02 pm
    • CH

      I’ve been having neck and upper back pain on descents too. Decades of riding and then spending time looking at the glowing rectangles have caught up with me.

      I’ve found that strengthening the upper trapezius muscles along with neck and shoulder mobility work has helped. Think shrugs and pulling exercises that are the opposite of a push up. Basically, trying to look up with my shoulders narrow doesn’t work for me anymore. Shoulders have to be back for me to look up from the drops these days and the exercises support that for me. Hope this works for you.

      February 9, 2021 at 12:16 am
  • Jacob Musha

    A quick internet search makes it sound like the Super Tuck is only a few years old, but I remember being introduced to it “way back” in 2009 when I first started riding road bikes. With 23mm tires inflated above 100psi, a pothole can slam a quill stem into your sternum. Unpleasant for sure, but fortunately I never crashed from it.

    February 8, 2021 at 1:17 pm
  • Dan Christopherson

    I’ve always thought that the super tuck was insanely dangerous, but even when I was racing Cat 1 back in the mid-seventies, I saw it used once or twice. Now, it seems fairly common. I used to use a “phantom aero-bar” position on time trials even before Pete Penseyres invented the aero-bar for the RAAM. They outlawed those in road races, probably a good idea also. Jan, you’re right about riding in the peloton… nobody should be in a sketchy bike-handling position The answer, of course is an integral dropper post. Figure that one out and market it!

    February 8, 2021 at 1:55 pm
  • Luis Bernhardt

    When I first started racing, back in 1972 in Northern California, we used a slight modification of the aero tuck, with the body further forward over the bars and butt off the saddle. But I like the standard aero tuck because the weight distribution is much better. Anyway, in conjunction with banning the supertuck, the UCI is also outlawing the forearms on the bars position. I think this is a more significant safety issue. Years ago, the UCI banned the Spinacci bars. The forearms on the bars position is the same as using Spinaccis, but without the Spinaccis! So if you ban one, you have to ban the other, I would think!

    February 8, 2021 at 3:11 pm
  • Todd Teachout

    It seems to me that the Super tuck is enabled by the bike market migration to limited sizes for carbon fiber bike frames. The short seat tube-long seat post configuration just begs for a rider to get off the saddle and jam their behind underneath the saddle nose inviting risk. I have not heard of any rider/racer dying or even being seriously injured from a crash from that position so the proposal may be premature. Another way UCI could reduce the risk would be to compel bike frame makers to offer more frame sizes. And/or limit the maximum distance between a top tube and a saddle. UCI has already imposed a minimum weight and dictated the frame configuration (double diamond). Dictating acceptable a maximum distance between a saddle and top tube could be easily evaluated by a official. Seems to me if the market can offer road bikes, gravel bikes, cyclo-cross bikes, adventure bikes, fixed gear bikes and others they can offer a bike with more frame sizes.

    February 8, 2021 at 4:15 pm
  • Nick M

    If you are not racing, why do you want to achieve maximum downhill speed? you just reduce your recovery time before the next climb…

    If you aren’t racing but really do want to achieve maximum downhill speed while remaining in full control of your bike and having some luggage capacity… why aren’t you riding a recumbent?

    February 8, 2021 at 5:03 pm
    • Jan Heine

      To question 1: Because going fast is fun. And in our rolling foothills, carrying more speed on the downhill means coasting further up the next hill, so you don’t have to pedal as much.

      To question 2: Because recumbents can’t really go on gravel roads very well. Or in other words, the upright bike feels like an extension of your body in a way that a recumbent doesn’t. Nothing wrong with recumbents, but it’s a different sport.

      February 8, 2021 at 5:52 pm
    • marmotte27

      To 1: I don’t use the aero tuck much for recreational riding, but I do, when I have to be somewhere on time (and look presentable there). More speed on the downhill = less sweat on the flats.
      To 2: Before you can coast downhill fast, you have to get up the mountains. Not much fun on a recumbent, unless you’re pretty strong.

      February 9, 2021 at 8:50 am
  • Dirt Road Dave

    As soon as I drop my dropper post on my “gravel bike”, I drop everyone near me, while coasting. If I still rode my “road bike”, I would definitely experiment with using a dropper. The additional weight might be worth using it, especially if it doesn’t take away from the handling quality of the bike.

    February 8, 2021 at 5:59 pm
    • Jan Heine

      Can’t wait to try a dropper post for going faster, rather than not going over the bars on super-steep drops!

      February 8, 2021 at 6:04 pm
  • Frank Krygowski

    About the Super Tuck, there’s this video:
    https://www.youtube.com/watch?v=byzvVc-FFSY&ab_channel=CyclingToday

    I agree that a handlebar bag seems to make one more areo. I use one on a bike with fenders and rather ordinary tires, but routinely outcoast my mates; and I’m not particularly heavy.

    But it pains me to push a boxy shaped bag through the air. I’ve made two of my own handlebar bags with somewhat smooth, curved shapes and no sharp protruding edges. Of course I haven’t tested them in wind tunnels, but they seem sensible to me. And I prefer their aesthetics.

    February 8, 2021 at 8:06 pm
    • Jan Heine

      Side pockets on a bag seem to increase the wind resistance. Beyond that, the bag’s shape doesn’t seem to matter much – we made a very rounded and smooth fairing for the wind tunnel, and it wasn’t any better than a boxy bag. The effect of the bag is more about closing a hole than creating smooth flow – there isn’t going to be laminar flow between the handlebars anyhow! A cyclist’s shape is very un-aerodynamic, with drag coefficient is about 0.9, compared to a modern car’s of 0.3. Our only saving grace is that our frontal area is relatively small!

      February 8, 2021 at 8:56 pm
  • Jeff Burke

    Imo, the super tuck becomes dangerous with inexperienced riders who do not realize that their knee now protrudes into the area of the front wheel. I’ve seen people get into the tuck and then start hitting their knee on the front wheel. They start wiggling the handlebars around, which also seems to be caused by lack of upper body strength. Some riders cannot get themselves planted on the TT so their weight is now supported by their weaker upper arms and they get fatigued quickly which causes shimmy and causes their knee to rub the front tire and becomes a dangerous situation

    February 8, 2021 at 9:05 pm
  • toujoursonroule

    Thank you for doing the testing, Jan. The aero tuck is definitely efficient and that is of course not only important for racers but also for randonneurs. We tend to conserve energy where we can and not pedalling downhill (against a strong headwind for example) because you can use the aero tuck is certainly a no brainer.

    I do wonder about your downhill speeds with a handlebar bag, though. Did you control those tests for weight? You are heavier with a handlebar bag, which should make you faster going downhill anyway, just like my enormous corona lockdown belly.

    I do not think that a handlebar bag is that bad aero-wise as most racers like to think. But I have a hard time following you that it could be actually benefial.

    February 9, 2021 at 12:39 am
    • Jan Heine

      You are right, the bikes with the handlebar bags are a bit heavier. (I carry stuff on the other bikes, too, in underseat bags, so the bag-plus-contents weighs about the same.) However, the speed difference of roughly 10% cannot be explained by a weight difference of about 1%. I’ll calculate this based on the wind tunnel data we have for the randonneur bikes and report back in a day or two…

      February 9, 2021 at 7:43 am
      • John B.

        Independent research shows that a small handlebar bag requires 8.5W additional power at 25km/hr. That contrasts with a bikepacking style saddlebag, which reduces required power by 2.5W at the same speed.

        https://www.youtube.com/watch?v=WcXh_oqs_Bs

        February 9, 2021 at 5:48 pm
        • Jan Heine

          I haven’t seen the YouTube video, so I don’t know whether they tested the bags in the aero tuck. Assuming they tested a standard riding position, what you mention matches Bicycle Quarterly’s wind tunnel testing: A Berthoud handlebar bag (with side pockets) increased wind resistance by about 2% when riding on the hoods. Even in the aero tuck, there was a slight increase in drag for a bag with side pockets. However, a small fairing (same size as handlebar bag, but smooth sides) decreased drag in the aero tuck by 2.5%. That seems to match the on-the-road experience – making the sides of the bag smooth seems to improve its aerodynamics significantly. It would be interesting to test the smooth-sided bag in other riding positions.

          We haven’t tested a bikepacking-style underseat bag, but in our book ‘The All-Road Bike Revolution,’ we mention that if it’s well-designed, it can act as a fairing and decrease drag by smoothing the airflow that comes off the rider’s body.

          The main reason to use a handlebar bag is that you can easily access your stuff, even while riding. During a long event, this saves more time than a small decrease in wind resistance. As you know from randonneuring, stopping one minute longer requires you to ride a lot faster to catch a rider who left a minute ahead of you.

          In the last PBP, I rode with a tandem until I had to stop and eat at a control. (They had support.) They had a head start of maybe 8 minutes. It took me three hours of riding at my max to catch them!

          February 9, 2021 at 11:14 pm
  • jakub

    Best advice I got when I started randonneuring was: “Never pedal on downhills, tuck”
    On PBP you are either going uphill or downhill, it helps a lot to rest half the time 🙂

    February 9, 2021 at 4:34 am
  • Mark McInerney

    What about the Cinelli “spinaci” handlebar extensions? They were once popular in racing…but, then they were banned (I believe because of some serious accidents in descents)…so why not bring them back?

    February 9, 2021 at 5:44 am
    • Bob Z

      Spinaci’s are brilliant! But finding them in 31.8, is pretty tougj

      February 10, 2021 at 8:39 am
  • Christian

    The better aerodynamics (crouching behind the main tube) is the reason why kickbikes (big scooters) are faster downhill than any bike. This has amazed many a cyclist.

    February 9, 2021 at 6:32 am
  • Phil

    Both positions increase the distance necessary to bring a bike to a stop. Maybe this is OK with experienced riders on a closed course but otherwise it seems foolish. Safety is more important than speed.

    I know its irrelevant but . . . I hope that Rene Herse will decide to make a 40T middle chainring.

    February 9, 2021 at 9:45 am
    • Jan Heine

      I agree that safety must come first. I wouldn’t use either position when there’s a foreseeable need to stop or slow down. If you’re going down a road with no cross streets or driveways, there’s usually little need to stop suddenly. Otherwise, the same argument can be made against going fast – it also increases your stopping distance.

      February 9, 2021 at 11:10 pm
  • Eric

    I used to have a Moulton with a Zzipper fairing. I could sit on the ‘top tube’ going down hills. Exhilarating is one word for it. lol. I miss that bike — descents were absolutely zero drama compared to any other bike I’ve had.

    February 9, 2021 at 2:32 pm
  • Bob Z

    As long as the surface flat or made even worse by pockets/flaps on said surface, it is way worse aerodynamically than an “unfaired” bike. Rando bikes are typically heavier than their UCI-minimum counterparts. Of course they will be faster on descents when just coasting.

    February 10, 2021 at 8:48 am
    • Jan Heine

      The racing bike wasn’t at the UCI minimum, either. And at a speed of 50 mph, 1% weight difference can’t really explain a speed difference of almost 10% – at that speed, aerodynamics are the most important factor limiting your speed, otherwise, you’d keep accelerating all the way to the bottom of the hill…

      February 10, 2021 at 9:05 am

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