Challenge has just upped the spec on two of their popular cyclocross tubular tire treads with a Team Edition Grifo and Limus.
The Limus, on left, is intended for “deep, soupy mud”, and the Grifo is more of an all conditions pattern that we’ve used with great success in North Carolina’s clay/mud/snow/grass/dirt mix. And that’s usually all in the same race. The tires use their CoreSpun cotton casing and have been raced by Jonathan Page, Jade Wilcoxson and Helen Wyman on the World Cup circuit. They’re a bit more delicate than other versions, so they really are intended for t0p level racing, but reportedly provide a dramatically more supple ride and allow for lower tire pressures.
Challenge’s Team Editions, like all of their tubulars, are woven round with a seamless latex inner tube sewn inside then inflated before gluing the tread on. They say this eliminates stresses on the treads that could occur if they were glued on flat then inflated. Claimed weights are 405g to 410g each with a retail of $129. Both are black natural rubber tread with a cream sidewall. One size  only – 700 x 33.