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ASK RICHARD: HOW MUCH TIME WILL I SAVE IF I USE A TIME TRIAL BIKE?
Richard Cunningham
November 3, 2008
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How much time or energy will I save if I use a time trial bike, as compared to my regular road bike? The TT course we use is mostly rolling hills and I am out of the saddle a good deal of the time when I climb. Wouldn’t my non-aero body position void the main advantages of a TT bike? If a TT bike alone gives a significant advantage, why don’t pro racers use aero bikes for regular Tour stages?
That’s a lot to answer, but you are in luck, because in the latest issue of RBA we just published the results of real-world and wind tunnel testing by Specialized, between their Transition TT bike and the traditional Tarmac S-Works. The bottom line is that the advantage of the TT bike alone saves thirteen watts at the enthusiast’s average speed of 20 miles an hour. That is like shifting one gear higher without additional suffering. Thirteen watts at such a moderate speed means that you will benefit from the bike’s slippery aerodynamics while you are climbing in any position. Thirteen watts is like having someone push you uphill with the pressure of two fingers. Testing also shows that a slightly heavier bike will not cost you a significant time penalty, because it is wind-drag, not weight that hurts you the most above 15 miles an hour.
If you bother to don the skin suit, aero helmet, booties and wrap-around glasses, and stay tucked in on a TT bike, the reduction in drag is 33-percent over a conventional bike and kit. To make that hit home, if you can produce 280 watts (pros can) you will ride 2.7 miles an hour faster. That, my friend, is a worthwhile advantage if you consider that, at the end of a one-hour TT, your identical twin will be trailing you somewhere in the distance-about three miles back. Let’s just say that your twin won’t be coughing up lame excuses to cover such a resounding thrashing.
Have bad news for your last question. The reality is that cyclists race against wind drag—not each other. Everything else—bike weight, gearing, rolling resistance and tactics, is secondary to the nasty pull of the atmosphere (14.8 pounds per square inch at sea level). Pro cyclists would gain a significant increase and speed and we would probably see more solo breakaways if the were allowed to use similar aerodynamic features employed by time trial bikes—but the UCI banned all such treatments from mass-start racing in an effort to even the playing field. Read the rules here. www.slowtwitch.com/mainheadings/techctr/ucirules.html I think it stole a lot of the excitement and technology from the sport.
It is almost comical that the UCI has no problem enforcing its ban against technological advantages in the peloton, yet it cannot make headway to stem the tide of illegal substance abuse. At least an aero bike is out there on the starting line for everyone to see. Maybe the UCI should reconsider, because in that light, their aero restrictions hold about as much air as a wind tunnel.
E-mail Richard Cunningham with any questions or feedback at AskRC@roadbikeaction.com |
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