What's Cool In Road Cycling

Carmichael Sez: Rain And TT Bikes Just Don’t Mix

TDF St. 13 Analysis – With a long individual time trial in the southwest of France, everyone knew weather was going to factor into the results of Stage 13. But instead of the oppressive heat we expected, it was rain that wreaked havoc today. This wasn’t just another road race, and rain makes time trials really treacherous.

– By Chris Carmichael –

A lot of riders crossed the finish line with torn skinsuits after sliding out in slippery corners. But these are professionals who train and race in the rain frequently, so why did so many fall anyway?

The essential TT position: max leg extension and a wide leg-hip angle require riders to move well-forward on the bike, making a less than ideal platform for bike-handling.

A lot of cycling enthusiasts go their entire riding lives without throwing a leg over a time trial bike, but if you’ve ever ridden one you know that they’re not just normal road bikes with aero bars. The geometry of the bike is a lot different, with a steeper seat angle and different dimensions for the top tube and wheel base. And a rider’s position on the bike is a lot different, too. It may be more aerodynamic, but it’s also a lot less stable.

To maximize power output, riders want as much leg extension as possible. On a time trial bike, this means a high saddle position. But it’s also important to have a reasonably large hip angle, which can be challenging to achieve when your upper body is low over the front of the machine to reduce aerodynamic drag. As a result, you have to move a rider’s hips forward in relation the bike’s bottom bracket (where the crank attaches).

Between optimizing the position of a rider’s hips to generate more power, and bringing his arms forward and close together on a set of aerobars, you’re also moving his weight toward the front of the machine. A high center of gravity located closer to the front of a bicycle makes time trial rigs more difficult to steer than a conventional road bike, and that problem is compounded by wet roads.

You might think that getting out of an aero position and riding with your hands on the outsides of the handlebars would be helpful for staying in control, and to a point that’s correct. But time trial rigs have become so specialized that they are really designed to handle best when the rider is in an aerodynamic tuck. When you’re riding more upright to have access to the brakes, your hands are far closer to your body than they normally are on your road bike, and this makes for skittish steering.

The standard setup for a time trial also calls for very high tire pressure to minimize the amount of rubber in contact with the road, and hence reduce rolling resistance. But when it’s raining, having more rubber on the road increases traction in corners. For a long time trial in the rain, you have to try and find the right balance between traction in the corners and rolling resistance for the long straightaways; and if you get it wrong you can have a hard time keeping the bike upright.

If there’s any upside to crashing in the rain, it’s that the same water that reduced traction for your tires also reduces friction when you hit the pavement. As a result, you slide over the road more easily and tend to lose less skin. But you still lose time, and that is what’s critical in a race against the clock.

Despite losing time, three of the top six finishers in Stage 13 crashed on their way to the finish line, which clearly shows there’s a fine line between pushing the pace and riding cautiously on wet roads. Having already crashed heavily in this year’s Tour, stage winner Alexander Vinokourov crept slowly through the most dangerous parts of the course and poured on the power on the safer, straighter portions. He rode extremely well to take back big chunks of the time he lost last week, and now he’s back in the top ten overall.

Beyond Vinokourov, Cadel Evans and Michael Rasmussen had the most impressive performances of the day. Rasmussen rode probably the best time trial of his career to hang on to the yellow jersey by a full minute, and Evans showed he has the time trial speed to complement his power in the mountains.

The big losers on the day? Alejandro Valverde and Christophe Moreau. I didn’t expect Valverde to lose so much time, and it was a shock to see him get caught and passed by Rasmussen. Sadly, Moreau’s poor performance was less of a shock. He’s always suffered from a lack of consistency, and it was pretty much inevitable that he’d ride himself out of contention at some point.

The next audio workout in the Do The Tour… Stay At Home™ series is Stage 13, a workout designed to prepare you for long individual time trials, download Stage 13 to your iPod at TrainRight.com.

Chris Carmichael coached Lance Armstrong throughout his 15-year cycling career. For more information on Carmichael Training Systems’ 9+3 Coaching Offer, the Do the Tour…Stay at Home_ audio workouts with Lance Armstrong, and our free Tour de France Newsletter, visit TrainRight.com.

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