MajorA

My 1987 road bike has the dreaded BioPace chain rings; not knowing any better because I've been on a mountain bike for the last 15 years, they seem fine to me. But I'd like to try convention chain rings, so that I can A/B them with the BioPace.

Here's the question: what brands and models of chain ring can I use with my Shimano 105 cranks? Between the progression from 6-speed freewheels (which is what mine has, with indexed 105 shifters front and back) to 7- and 8-, and now 9- and 10-speed; Shimano's change from Uniglide to Hyperglide; different chain widths; and the possible incompatabilities between 105, 600/Ultegra, and Dura Ace ..... I'm really, really, confused.

Thanks.

SpokesInMyPoop

wow... you're asking a lot.

and you're due for quite a response.

maybe you could find something on sheldonbrown.com.

wow. i understand why you're confused, tho. just make like me: don't bother with it and just do it.

wtf?

grolby

Hey, MY 1987 road bike has BioPace rings, too! (Post soon, pending retrieval of photos!) I also have that same 105 group.

I've only done a few miles on this bike so far, but I'm pretty happy with the rings. They feel fine to me. Why bother swapping them out? But if you must, here's the deal: don't worry about it. Just match up the BCD, and you're good to go. For 105, it should be 130mm, but it might be 110. I don't know what BCD sizes BioPace came in. So make sure you know what it is. Other than that, don't worry about it. You can use whatever brand of chainring you want. The only possible issue is that 10-speed chain may wedge itself in-between the two rings, but I don't think that this is terribly likely. I'm using old cranks and chainrings from the 6-speed era with 8-speed equipment, with not even a hint of trouble. Obviously, not the same as 9 or 10-speed on the same rings, but from what I hear, problems are pretty few and far between.

John E

The primary concern is bolt circle diameter, which is probably either modern Shimano road standard (130mm) or old school mountain (110mm). Both are very easy to find.

clayface

I think that in '87 Shimano still had the Uniglide freehub bodies around. Finding a replacement cassette for the old system is very, very difficult so IMO prior to a chainring overhaul, I'd go for a 7sp freehub replacement since 7sp casettes are easy to get. Or if you want to keep the original 6sp shifters, by using a spacer, you can use only 6 cogs from the newer cassettes. Of course, this will convey a redishing of the wheel and a respacing of the axle.

cyclotoine

Your question is confusuing and you need to break down into a serious of numbered questions for which a definate answer will be. As most have said just swaping out the rings with any other kind as long as the BCD is the same will be fine. Of course you do not want to buy new expensive shimano 10-speed rings, there is no point. By some other aftermarket brand. 10 speed and even 9 speed rings are thinner and will wear quicker. If you are running a 9-10 speed set up you will want 9/10 specific rings. You may also be able to get more help with a question like this in the mechanics forum.