Le Tour 2019 - Stage 13


Explosive, that’s how I feel after seeing today’s individual stage. Everyone was expecting, Alaphilippe to lose some time in the TT. However, many thought that Alaphilippe would still retain his maillot jaune, just that the gap between him and Thomas would be significantly reduced. Yesterday, I was convinced that Alaphilippe would remain in yellow, but I was shocked that he beat the GC riders, and indeed everyone else. Explosive is, in my mind an understatement. I’d think that Thomas, and the others are now seriously concerned for tomorrow’s stage in the Pyrenees. If Alaphilippe doesn’t lose time on the summit finish of the Tourmalet.. well then who know’s what will happen.

The time trial is a great stage. Like the mountains, it plays directly to your fitness. Skills, tactics, and bluffing are reduced to a minimum. For riders who want to win the Tour, then they need to be able to TT, if not at the highest level, then close to it.

But, what decides how good you are at TTing? Your performance is related to your FTP, and your MAP, but is also dependent upon how aerodynamic you are. Your ‘aeroness’ is measured by your coefficient of drag (CdA), which is affected by a variety of measures, including, but not limited to, your height, your mass, your body shape, your frontal area, and importantly, the rest of you (i.e., a full 360o). Equipment choices, and positioning are extremely important. All the GC contenders, as well as people who will be targetting the TT stages will have been to the wind tunnel, or similar to ensure that they are aerodynamically optimised.

Years ago, it’s likely that other than one or two riders everyone else left their TT bike to race day… However, anyone who has ridden one, with a power meter, will know, that even though they will ride faster than a road bike, if you just rock up and ride on race day your power output will be diminished due to the change in position and tighter hip angle. Now, the main players at least will be riding their TT bike at least once a week so that they can learn to close the gap between the power they produce at FTP on their road bike and TT bike.

It’s quite possible that in today’s stage Alaphilippe and Thomas, and the other main players will have been averaging at least 6 W/kg. In other words, if a rider weighed 70 kg, then their power would have been at least 420 W. However, it’s more likely that riders would have been around 6.5 W/kg (455 W) for the first 5 or so. Potentially, they could have been higher (as this power output has been managed for the Hour Record). In terms of aerodynamics, for the smaller riders I’d imagine that their CdA would be 0.2 m^2 or less.

All in all, today’s stage was explosive. There’s been some great stages so far, and now tomorrow’s stage to the Tourmalet should be absolutely crucial. I’ll call it now, and say Alaphilippe will still be in yellow at the end of tomorrow’s stage.

Richard Stern