Originally Posted by
mike02101973
Hi picking up on this older thread again.. Just a quick question regarding replacing 42t chainring (130mm bcd) with 39t on early 80s shimano 600 groupset.
Is there anything I would need to be aware of in terms of compatibility?
Friction shifters will make almost anything that you can bolt on work. That means the only compatability issue you have to consider is bolt-circle-diameter. That's the good news.
The bad news is that it won't make very much difference. If you're looking for an easier hill climb gear you can pretty much just add the cost of the 39t chainring onto whatever you eventually buy to get the low gear that you're looking for.