Crank question

[Bud]

I'm kind of a new at this build stuff, so bear with me.

Can you take an Ultegra compact crank that's 39-48 and put a smaller little ring on it, say a 36? Does someone make such a ring for this crank?

Thanks-

[DfCas]

An Ultegra crank is not a compact crank. An Ultegra crank has a 130mm bolt pattern and will accept a minimum 38 tooth on the inner.

The R-700 is a compact crank with a 110mm bolt pattern.It will accept a minimum 33 on the inner,but they are rare.34's are quite common.

Hope this helps.

dan

[Bud]

That makes perfect sense. . . thanks for the info.

[Marburg]

What DfCas said is spot on. In terms of "quite common," you can get the variety of 110BCD "compact" rings through your favorite bike shop's QBP catalog. At a minimum FSA (who are whole-hog on the compacts) and Salsa make nice rings.

And of course, since it's the inner ring, you don't need to pay a ton for ramping and pinning and all that.

[531Aussie]

yeah, if you check out a 39t ring, you'll see how close the 'rim' is to the bolt holes -- there's not much room for shrinkage.

[bigbill]

You can get a 38T 130bcd chainring, a 38/48 is a common cyclocross setup. I run a 39/48 on my commuter, I considered a 38, but found that I spent most of the time on the 48.