so i decided to rebuild my bianchi axis and upgrade the junk stock components, but i may have jumped the ***. i got some 07 campy parts, including some campy ultra torque cranks. today i installed them and come to find out theres not enough clearance for the chain. they're compact (50-34) and i just assumed it would work. well, it doesn't, and i have a bad feeling it's not to be. the 50 chainring just clears the stays and with the chain in place rubs.
i'm at a bit of a loss as to what to do next. a 48 tooth might work, but it's tight all the around. the crankarms clear the stays by a few mm at most. any advice?
i'm really bummed at the moment....
My interpretation was that the 50t chainring is rubbing the stays, when under tension from the chain. Campy UT is designed for road machines, and I imagine the extra chainstay width for CX clearance is giving the OP problems.
I have a Veloce UT crankset on my road bike. It's an outboard bearing cup system, and the half the axle is attached to each crankarm. the two halves have interlocking teeth, and are joined by a 10mm bolt. It's wonderfully stiff, but is very picky about BB shell width tolerances. In fact, I'm pretty sure that my previous cup spacer suggestion wouldn't work because of this.
To the OP, you might try a X-post in the Mechanics forum.
i did post it in the mech forum, but actually solved it today. the chain wasn't rubbing on the stays, i was a bit too tired when i made the post, but the chainrings and crankarm are very tight to the frame, however i took it by a trusted mechanic and he told me it was well within the acceptable range, which was what i was hoping.
Bruce, please explain ..... In the first post you said "the 50 chainring just clears the stays and with the chain in place rubs." Then you say it's okay.
Did it NOT actually rub?
well i posted my original post after a long day of work and wrenching and a couple glasses of wine. the chain rub is a non issue, i was looking at the bike form a weird angle when i thougt the chain was going to be an issue but i was seeing things basically. the chain doesn't rub, which i realized as soon as i pulled the bike down off the hook. the 50 chainring does come close to the stays, i think a 50 is about as big as you can go, and the crankarm comes close to the stay as well. according to a very trusted mechanic (who also owns an axis) none of these clearances are so close to be any issue.
sorry for any confusion, it was i who was originally confused.