Originally Posted by thechamp

I helped a friend of mine build up a road bike and we've been having trouble getting the front deraileur to shift properly. (Double crank)

My friend's a little short so, not finding any good shimano used cranksets in 165, we used the 165 double off of a mixte I've got, I think they're suginos. Anyhow, like I said, I'm having trouble adjusting the front deraileur (shimano 105) with the sti brifters (shimano 105). The difficulty is in setting the limit just so so that it makes it up to the big ring but doesn't fall off the other side. I'm making quarter turn adjustments and I just can't get it right. I don't think it's me, and I don't think it's an sti problem but what do I know?

Looking around a little I've seen a bunch of hooey about ramps and pins so I figure that's just the little bit of help we need to get the chain to climb up to that big ring without the deraileur shoving it too far. So I went to LBS and found a used ring (53 - same size as the one we've got), shimano, ramped, pinned. It's labeled shimano sg b-53. From looking around I gather the B indicates compatibility with a 39 tooth small ring, although Sheldon Brown suggests it will still work quite well with the 42. I can't get a look at the bike at the moment because it's in another state, so I'm not sure if it's got a 39 or 42, but I'm almost certain that it's not a shimano small ring. Will this matter signifcantly? Should I be looking for a 39 ring as well? Or, more specifically, should I be looking for a Shimano 39? Or, will I see significant enough improvement with the big ring to let it go for now? I'm just trying to cover all the bases before dropping this thing in the mail.

Thanks in advance for any advice.

Dan

BTW, I know I should just buy a new matched pair but I don't have the scratch at the moment.