Are all 42T chainrings the same outside diameter?
I replaced an old aluminum 42T chainring with the stainless Surly. Now my back wheel sits forward enough that I might need to add a link to the chain. What I am saying is that the wheel used to be pretty much centered in the drop outs (not track drop outs) and now it sits way forward. Here is a before shot, I do not have an after shot.
My math is telling me that the OD of the chain ring should be the same... but I'm no math man.
they are with very slight variation due to teeth shape.
also, an old/worn out ring (esp. alu) will have some wear.
Originally Posted by Santaria