Classic & Vintage - Crank swap info/advice for 1988 Miyata

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bigbossman
04-27-05, 09:02 PM
I have a 1988 Miyata 215ST with 170 triple cranks. I'd like to try 175's, so I'm soliciting advice on how to best accomplish the swap. from what I can tell, I don't need to change out the chain rings on the drive side, as the crank arm itself seems like it is a separate piece that is bolted onto the chain ring assembly.

So, some questions come to mind:

1) Is this true? And if so, how do I establish what replacement crank would be a bolt on replacement?
2) Do I need to know center-to-center on the bolt pattern? What else needs to be considered?
3) Any ideas on where I could look for a good set of reasonably priced replacements?
4) Anyone have a set laying about that I can buy/trade for?

Regards,

John D.

luker
04-27-05, 09:43 PM
not familiar with the bike; the rings usually detach from the arms. You'll need both sides, of course, so that you don't develop a marked limp when not riding the bike.
I know its a boring answer, but 175's are sorta uncommon; ebay is the place that you'll find an appropriate replacement (unless, like i said somewhere else, you're buddies with the guys at the LBS and they let you root through their junk...) There are about a hundred different bolt patterns and combinations - if you post the brand (and any other identifying features) there's someone here who can tell you the size (maybe even me if its really easy). I have no 175's except for a pair on the old time-trial bike; not triple, and maybe a little sentimental attachment. Kind of like being attached to an instrument of torture, or maybe an ex wife.
bigbossman
04-27-05, 09:56 PM
There are about a hundred different bolt patterns and combinations - if you post the brand (and any other identifying features)

They are marked "SR Japan 170" on the back, and the front of the drive side has the word "Signature" in script. The center plug over the retaining bolt says "Miyata Cotterless". The large and middle chainrings are marked "SR 307" and SR 341", respectively. These are the stock cranks that came with the bike when sold new.

Regards,

John D.