CHRIS CARMICHAEL EXPLAINS WHY BANNING THE SUPERTUCK IS FUTILE

By Chris Carmichael, Founder and Head Coach of CTS

So, cycling’s governing body, the Union Cycliste Internationale (UCI), has decided to enforce a ban on the ‘supertuck’ cycling position in the pro peloton because they say it is dangerous for the rider and riders nearby. I’m not as involved with pro cycling as I used to, so maybe I’m missing something, but pro cyclists crashing due to the ‘supertuck’ position doesn’t seem to be a notably frequent occurrence. Riders hitting ‘road furniture’ or crashing from poorly designed courses and poorly placed barriers? That happens way too frequently. Riders hitting or being hit by motos or support vehicles? That seems to happen way too frequently, too. But sure, ban the ‘supertuck’ and keep monitoring sock height.

Comment sections on social media and cycling websites suggest the supertuck was banned so the pros don’t set a bad example for amateur cyclists. If there were even a shred of truth in that it would be like making NASCAR drivers stop drafting so they don’t encourage tailgating on the highway. Professional athletes have better skills than normal people, and they are competing in a (theoretically) more controlled environment than amateur athletes. (Plus, there are Youtube channels dedicated to descending videos – including the ‘supertuck’ – that have millions of views…) There are a lot of things pro cyclists do on the bike that you shouldn’t do. Hell, there are a lot of things I used to do on a bike as a pro that I don’t have the agility, stability, or risk tolerance to do anymore.

For amateur cyclists I view the ‘supertuck’ descending position much the same way I view ‘marginal gains’. For most athletes, there is still plenty of room for improvement in fundamental training and handling skills, so you’re more likely to increase downhill speed more through learning to brake and corner better than by squeezing yourself onto your top tube.

That reminds me of a conversation with AMA Motorcycle Hall of Fame racer Miguel Duhamel, who said during his career he rarely, if ever, rode a motorcycle on the street. His focus was on racing motorcycles, which meant riding bikes with very specific technical setups, designed to go fast on closed tracks with safety equipment. Not only was riding on streets not as fun, but he perceived it as way too risky because of the massive differences in equipment (which necessitated different riding styles), the different surface conditions, and dangers like light poles and mailboxes that made the penalty for failure extremely high. Most of all, though, he didn’t want to ride a motorcycle in traffic with other vehicles and motorcycles – because of their skill and focus levels (or lack thereof).

Let the pros be pros. Even they know the difference between descending on a closed road in a race and bombing through the suburbs on a Tuesday.

Does the ‘Supertuck’ even matter?

When it comes to the ‘supertuck’ position in road cycling, which is defined as the rider crouched over the handlebars and sitting on the top tube, I struggle to see much of a benefit from banning it in the pro ranks. However, based on aerodynamics research from Blocken et al published in October 2018 in the Journal of Wind Engineering and Industrial Aerodynamics, I also don’t think banning the position will dramatically change race results.

The study examined 15 rider positions and the differences in aerodynamic drag and reduction in speed during a simulated 5-kilometer straight descent without pedaling. The “Froome position”, made famous from his descent of the Col du Peyresourde on Stage 8 of the 2016 Tour de France, looked extreme but turned out to be only the 7^th most aerodynamic road bike positions (three time trial positions were also tested in the 15). The image below includes the road rider positions tested. The figure uses the fastest position, “Top tube 4”, going 20 meters/second for 5 kilometers as the reference, and then shows the percentage reduction in speed, and the resulting increase in elapsed time, for the slower positions.

In the aerodynamics study, three variations of ‘top tube’ positions were in the fastest six of 11 road examples. The “Pantani” position (chest on the saddle and butt behind the seat post) is an anomaly. It’s third fastest, but rarely used because… it’s insane. The last two of the top six fastest are ‘back down’ positions where the rider’s rear end is still on the saddle. These are still legal.

Wind Tunnel vs. Real World

The ‘top tube’ positions are faster, but not by that much, especially considering that a 5-kilometer straight descent with no pedaling exists only in a wind tunnel or a computational model. The researchers openly recognize this in their discussion. That it’s not a realistic real-world scenario doesn’t invalidate the data. Those positions are faster… when you can use them. And that’s what closes the gap between the speed of a ‘top tube’ position and a ‘back down’ position.

In real life, cyclists don’t stay in any static position very long on a descent. So, let’s say you average 50kmh on a 5km downhill with curves and corners and varying steepness. It would take 6 minutes to get to the bottom, and out of the six minutes you might spend 10-30 seconds at a time in a ‘top tube’ position, and then have to get back up to brake, turn, pedal, and accelerate. It’s not that the time spent in a ‘top tube’ position won’t be lower drag, it’s that the advantage is whittled down by all the moving around to the point that banning ‘top tube’ positions isn’t such a terrible loss.

Is it necessary to ban the ‘supertuck’ for pros? Probably not. Will it make much of a difference in speed? Probably not. Will it make pro riders take fewer risks on descents? Absolutely not. And will it keep amateur riders from descending more aggressively than their skills can support? Not a bit.

References

Bert Blocken, Thijs van Druenen, Yasin Toparlar, Thomas Andrianne. “Aerodynamic analysis of different cyclist hill descent positions.” Journal of Wind Engineering and Industrial Aerodynamics, Volume 181, 2018, Pages 27-45.
https://doi.org/10.1016/j.jweia.2018.08.010.

Race photos: Bettini