Vintage cranks compatible?
 

My bike has its original TA cranks from the 1970s that I'm looking to swap out b/c I don't like the 49/40/28 chainring sizes.

I'm assuming that when I see vintage French cranks on eBay (TA, Stronglight, Peugeot, etc.) I can trust they are compatible with my current square-taper BB, my current crank bolts, and my current original pedals.

Can I also make that assumption for 1970s and 80s Shimano, Campy and other makers' cranks, if they show a square BB hole? Might there be a problem if the replacement crankset comes without its matching crank bolts?

Many thanks in advance!

what sizes are you looking for? I have a 52/45 TA crankset...

Wouldn't make more sense to change the chainrings on your present crank? I assume it's a Cyclotouriste. You can still get rings for it. I just bought a 52 for $12 on eBay.

In answer to your question, you can assume nothing. Do you have French pedal threads? Will a BB for a triple be too long for a double? Not all square tapers are the same. The Japanese use a different standard. If you have French bottom bracket threads, it's really going to get ugly.

Maybe changing the chainrings on my present crank, a Cyclotouriste, really is a better idea.

cyclotoine, I am interested and I sent you a PM - just wanted to confirm you saw it.

Dirt, you did really well paying just $12 for your 52 ring on eBay. I just paid $37 for a 34 ring to replace my 28. Hopefully the sale of my 28 will make it a wash, or almost.

A 52 is coming up for auction again, we'll see. (My LBS has the TA 52s and 53s but at $60 and $70.)

I just saw this Cyclotouriste ad posted on CL. It's local to me, so I can act as your agent if you want to arrange it.

http://sfbay.craigslist.org/eby/bik/247389348.html

You can get a good range of TA rings new. Harris cyclery, among others, stocks them.

http://sheldonbrown.com/harris/frenc...ks.html#bottom

bossman, many thanks for the offer. Great idea, but it looks like the ring sizes posted on your local craigslist are not what I need (and then there's the motley collection of damaged and orphan crank arms ...). My TA rings are 28/40/49; I just got a 34 inner to replace the 28 (overpaid $37, would have loved to get your local 33 for $16 OBO); now looking for a 52 or 53 outer.

Hoping at the end of the day it will all shift properly without also replacing the front derailleur. It's the original Suntour Cyclone from 1977, a double derailleur over a triple crankset. It was unable to upshift from the 28 to the 40. The 28 was only an "emergency gear" for hard climbs that you had to get out of by stopping and manually lifting the chain. I'm hoping it will shift fully between 34/40/52 or 53.

TA rings are available here and there, just not usually cheap ...