Hi pyrahna,

If the cobbles are dry, a 24 mm tub is enough, and the stock R3 works.

But if the cobbles are wet, some riders prefer a 27 mm tub, and the stock R3 doesn't work.

Of course, we're making the bikes for the team long before the weather forecast is firm, so we have to "hope for the best and prepare for the worst."

Cheers,

---

Damon Rinard
Engineering Manager,
CSG Road Engineering Department
Cannondale & GT Bicycles
(ex-Cervelo, ex-Trek, ex-Velomax, ex-Kestrel)