We claim the Vire is about ninety seconds quicker than a Col over twenty kilometres. It is the only performance number on this website and it took two winters, eleven frames and one very long argument to be able to write it down.
The tunnel at Saint-Cyr-l’École is not glamorous. You book it in half-days, you drive up the night before with the frames in the back, and you spend the first hour discovering that the mount you machined in Annecy does not fit their balance. We had eight half-days over two winters. Six of them were useful.
What we measured
Drag at 45 km/h, yaw from −20° to +20° in 2.5° steps, with a rider on the bicycle rather than a frame on a stick — because a frame on a stick tells you about the frame and a rider tells you about the bicycle. Luc rode all of them. By the fourth session he could tell which frame was under him from the noise before we showed him the trace.
The honest summary is that most of what you can win is not in the frame. Position is the largest term by a long way, then the wheels, then the bar, then the helmet, and only then the tubes. A frame that is genuinely faster than another frame is worth perhaps eight watts at 45 km/h, and eight watts is not nothing but it is also not a marketing department.
Eight watts. Over twenty kilometres at forty, on the flat between Annecy and Ugine, that is about ninety seconds. We are not going to round it up.
The argument about seat tubes
The Vire’s seat tube is cut away behind the rear wheel and carries an integrated post. That is the standard answer and it is worth about a watt and a half — measurable, marginal, and the reason the frame is 110 grams heavier and much harder to travel with.
Luc wanted a round post. His argument, which he made for eleven months and which I did not want to hear, was that a rider who cannot get the saddle where they want it loses more than a watt and a half. He was right. The compromise is the one in production: an integrated post, but cut to your fitting numbers in Annecy and with two heads that give ±14 mm of setback, so nothing about the fit is a compromise even though the shape is one.
Where the number is not true
Above 34 km/h the Vire is quicker. Below it, it is a heavier Col. On a col it is 110 grams of nothing you want. In a crosswind on 62 mm rims it asks more of you than the Col does on 38s, which is why we say the wheels matter more than the frame and then sell you the shallow ones by default.
If you ride alone, on rolling roads, at speeds you would be embarrassed to describe to your friends, buy the Vire. If you ride up things, buy the Col. If you do both — most people do both — buy the Col and a second set of wheels, and we will tell you the same thing in the fitting room.
Céline Mareau · Annecy · 19 September 2024