I have a cooper and there is room for a 25c. As for ride, that depends on the bike. The cooper is supposedly a stiffer ride than the R230, but compared to my previous Fuji 08 CCR3 carbon and 09 Giant Defy Alliance, the ride is WAY smoother yet its stiff. My previous carbon bikes were way way too buzzy, my hands would go numb within the first 30 minutes. I could ride the lynskey all day and not get that buzzy feel. Now compared to my 2010 Tarmac, the ride quality and smoothness is the same, but the Tarmac somehow has a hollow feel to it, while the Cooper has a more solid feel. The Tarmac being a much stiffer bike. I ride the cooper more than the Tarmac.