Technical FAQ with Lennard Zinn: Pro riders’ wheels
The wheels are arguably the most important part on a bicycle and are thus the source of constant efforts for improvement, and, for a team, to find an edge over, or at least parity with, the other teams.
There are a number of physical properties of a wheel that teams have to consider. A gram of rotating weight out at the rim is worth about two grams on the frame, so weight reduction is obviously critical. Wheels are big egg beaters of the air, and any reduction in their aerodynamic friction can pay off, especially when the rider is not sheltered in the peloton.
In order that the rider can transmit energy with minimal losses into forward motion, vertical stiffness and lateral rigidity are critical, especially for a big sprinter. Finally, the rider depends on the wheel for safety, but in more ways than you might think at first glance. Obviously the wheel must be strong and not collapse, get deformed, or break spokes during hard efforts or hitting bad bumps. Perhaps even more importantly, though, it also must stop well. The rider depends on the ability of the brake pads and the rims to generate friction on each other.
Telekom, Mapei and Rabobank have all adopted deep section carbon rims for all of the road stages so far. That is perhaps not overly surprising, until you consider that the wheels these teams are using do not have aluminum braking surfaces. The tendency of carbon braking surfaces to grind brake pads down to nothing, particularly in wet weather, as well as to not brake consistently, has been their Achilles heel in the past. On the other hand, you can build a strong, stiff wheel that is very aerodynamic out of composite fibers, and if the builder does not have to attach an aluminum braking surface to it, the weight can be held down further yet.
Especially after winning the prologue and the first yellow jersey, Christophe Moreau of Festina rates highly enough to get a pair of the new Mavic Ksyrium SSC SL wheels. The extrusion (the piece of aluminum pasta the rim is bent out of) is the same as the 2001 Ksyriums, but the machined areas between the spokes save 40 grams per wheel.
Confidence in Corima’s orange cork brake pads has led to Telekom and Mapei using these wheels. The black Corima pad holders come apart in two pieces and are held together with long, thin screws across the back of the pad. They work so well that Kevin Livingston was surprised after the first couple of stages to discover that he had been using wheels with carbon braking surfaces. Rabobank, on the other hand, is using special green pads on the rear and gray pads on the front in standard Dura-Ace pad holders.
Mapei’s deep-section wheels are Ambrosio XCarbo, while Telekom’s appear to be these same Ambrosio XCarbo rims laced to black Campagnolo straight-pull-spoke hubs so they look like Campagnolo Bora wheels. On Jan Ullrich’s time trial bike, a Campagnolo Bora sticker has even been slapped onto one of these wheels to make it look like that is what he is using on the front. Rabobank uses Fir Santara deep-section rims.
Bonjour is using Spinergy wheels, most of which are the Rev-X carbon 8-spoke versions with yellow dots painted on the spokes. Some bikes have Spinergy lightweight wire wheels as well.
Mavic-sponsored teams are using both Ksyrium and Cosmic wheels. U.S. Postal has been so far using standard Ksyriums on all of the bikes in the road stages. Festina has been doing the same thing, with the exception of Christophe Moreau.
Whether it is just that his stock went up after winning a stage and wearing the yellow jersey, or he already rated enough with the grantors of wheel schwag at Mavic, Moreau’s wheel are the new Ksyrium SSC SL versions for 2002. The SSC SL rim extrusion is the same as the 2001 Ksyriums, but they have been machined down in between each pair of spokes for a weight savings of 40 grams per wheel.
There seem to be no Rolf carbon wheels around this year, but his work is there in the Bontrager Race X-Lite wheels of AG2R. They have paired spokes coupling what Trek used to call Rolf rims to Bontrager hubs. They seem to be working fine, too, as Jaan Kirsipuu just won today’s stage on them!