how can I tell if I've bought the right chainrings?

ben-----
ben----- Posts: 573
edited December 2013 in Workshop
I've just bought two new chain ring replacements. Not too expensive on ebay. But I'm now worried I may have bought incompatible ones. They're certainly not identical to the old ones. I'm just hoping the differences are cosmetic.

The chainrings on my bike at the moment are Campagnolo, oldish, maybe mid 90s. 52t and 42t. 8 speed. The replacements I've bought are 52t and 42t, Campagnolo. The bolt circle diameters are the same on the old and new ones. But I don't know what speed the new ones are. How can I tell if I've got the right ones? Should I just try replacing them and see, or is there a way to tell without taking the old ones off and putting the new ones on somehow?

Thanks.

Comments

  • Is the BCD is the same, they'll be fine
    left the forum March 2023
  • JayKosta
    JayKosta Posts: 635
    Just see if the teeth of the new rings will fit into the links of your chain. If the teeth on the new rings 'bind' then there's a problem.

    Jay Kosta
    Endwell NY USA
  • ben-----
    ben----- Posts: 573
    OK thanks.

    I've taken the old chain rings off making it much easier to compare. They look similar enough. The main difference is the outer chain ring is thicker where the bolts go and on the inner part of the main ring (about 2.8mm vs about 4mm). I think it'll be OK though.

    Thanks.