Originally Posted by
Litespud
never had this problem with Campagnolo 10sp and SRAM 9sp chains, and I ran 13/26 cassettes with consecutive 13-19. However, when cleaning the cassettes I could see where the chain rivets rubbed on the next larger sprockets, so the spacing was certainly close, but the whole system ran smooth and quiet
Campy 10-speed cassettes are slightly wider spaced than Shimano or SRAM (which is why Campy 11-speed cassettes fit on their 10-speed freehub bodies) so a 9-speed Shimano, KMC, etc. chain worked well enough on Campy 10-speed cassettes. As noted above, a lot of riders used 9-speed chains on early Campy 10-speed bikes to avoid the expensive and complex Campy chains.