Olympics

Technical FAQ: Did baggy gloves slow down the U.S. track team?

Lennard Zinn answers questions about the U.S. pursuit team's baggy gloves, the fastest way over a bump in the road, and Bookwalter's TT crash.

Dear Lennard,
What do you think about the marginal losses of the US women’s team pursuit on those gloves? Talk about floppy; I’m not sure these are fit for gardening!
— Alan

Dear Alan,
Well, those gloves do look comfortable! And I have no experience maneuvering a bike like that with such precision on a track at high speed; perhaps the gloves made it possible to do things that would otherwise be more difficult.

It does seem surprising, though, that the US team was wearing such bulky, loose gloves, given how sleek and aerodynamic all of the rest of their equipment is. Since the hands are the first thing the wind hits of the rider and bike, and they are moving so fast (57kph average, or 35.4mph), I would think that reducing the size of the hands should cut aerodynamic drag measurably. It would seem analogous to Specialized’s wind tunnel result that shoes are faster without shoe covers by virtue of making the feet appear smaller to the wind.

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I don’t know how much time, if any, that racing without gloves might have saved over the 4K team pursuit, but it does beg the question: Could that have saved as much time as the left-side drivetrains the team was running? Felt engineers found that the left-side drivetrain was consistently faster in wind tunnel simulations of team pursuit on the track than a right-side one. The argument for it is pretty esoteric (based on sidewinds) — more than the straightforward aerodynamic argument for reducing the size of the hands stuck out in the wind ahead of the bikes. If Felt thought that it made enough of an aerodynamic difference to put the drivetrain on the left side bikes, it does seem like eliminating bulky gloves might be showing up in a list of small aerodynamic gains.

And it is possible that the U.S. team did test the gloves in the wind tunnel and found that they created no additional drag. I would be surprised at such a result, but I’ve seen many surprising results over the years from wind tunnels, like Floyd Landis’s “praying mantis” position on his aero bars being faster than with his arms flat.

In short, I don’t know the story behind the U.S. Team’s choice to wear those gloves, but it does seem like they might have been able to go without gloves like the British foursome did. It looked like the Brits had chalk on their hands; perhaps that was for the same reason that the Americans wore gloves.

In any case, the Americans rode a great race that was exciting and fun to watch, as did the British team, and their precision and speed were magnificent. They earned medals they can be very proud of.
― Lennard

Dear Lennard,
I read with great interest your article about physics and the bike throw.
I would like to ask you a question about the same topic.
Here it goes: If you are in a race, going at a good speed on a flat road and see a speed bump ahead of you, what is the best way to preserve your speed? Do I jump over the bump or is it better to just roll over it?
— Hernan

Dear Hernan,
Great question! It certainly depends on the size and shape of the bump.

Especially if it’s a tall or sharp speed bump that a pack of riders is bearing down upon, the most prudent thing would be to treat it as a very short neutral zone. Coast, spread out a bit, and even brake lightly if necessary. It’s always better to get to the finish than to end up lying on the road. Jumping the bump or banging into it at high speed can both lead to crash scenarios if you’re in the middle of a bunch of other riders performing similar maneuvers. Of course, if you are alone, chasing off the back or in a time trial, you would be interested in safely maximizing your speed through that section.

Speed bumps, in order to get the attention of drivers, are generally quite abrupt. Of course, some are smooth, raised sections with a crosswalk on top. For a smooth bump like that, you can probably just keep pedaling, and if it’s tall enough that it accelerates you upward rapidly, then unweighting the bike and coasting on the up side and pedaling the down side would make sense.

If you’re zooming up on a sharp speed bump, however, and you’re alone and have a clear line, then jumping the bike over it is going to be faster than hitting it at speed. You do expend some energy in jumping, but impacting the bump would decelerate you and bike and take away much more energy from your forward motion than jumping would. Additionally, you run the risk when pedaling straight into a sharp bump of pinch-flatting, damaging a wheel or two, or otherwise sustaining some bike damage. And you can get deflected enough to one side or the other to lose control or bump another rider.
― Lennard

Dear Lennard,
Your last article on Mara Abbott’s fourth place hit the spot . Most amateurs participate in sport with the “Olympic Spirit;” we just enjoy the competition and the training and we are happy. Maybe after some time has passed since getting nth place where n>3, we will forget the result.

In the Olympic men’s time trial, an American (Brent Bookwalter) crashed in the first turn. This experienced rider clearly hit the front brake, as the front wheel stopped turning while he was still upright. The three-spoke aero wheel makes this apparent.

One wonders how often a crash in a turn, like Froome’s crash in the Tour de France, may have been caused by the rider having the reflex to brake in the turn and not knowing it.

All kinds of data is already collected and transmitted on the rider; why not collect data on the bicycle like the brake signals and wheel RPM at a high data rate like in Formula1 car racing? With this data, crash forensics will be more relevant, and safety could be improved.
— Pierre

Dear Pierre,
That sounds like a great idea. However, to the best of my knowledge, obtaining that data still requires some fairly bulky and heavy equipment attached to the bike. I think even fairly recently I have seen mountain bikes equipped with accelerometers to measure suspension performance that had some pretty big, heavy data-acquisition components attached to the bike.

Maybe we are to the point where technology does allow us to attain information like that while still keeping the bike at the UCI weight limit and not adding significant aerodynamic drag to the bike. If so, I think it would be useful and fascinating to find out exactly what the riders are doing with their brakes leading up to a crash.

Years ago, a friend of mine sustained a serious head injury avoiding hitting a car that had pulled out in front of him while he was descending, and I am still scratching my head to figure out what exactly happened. He did not hit the car, he had no marks on his body other than to his face and head, and his bike was unscathed. He was as experienced of a road rider as there is, having raced successfully from a young age. To have data records from his bike could have clarified the sequence of events, and possibly a way to teach rider skills or improve brakes could have emerged to prevent future similar crashes.
― Lennard