1989 Specialized Rockhopper Replacement Chain

maherjf

I have a 1989 Specialized Rockhopper Comp 26” with Shimano Deore LX mech that is my daily driver. The original chain lost a roller so I had it replaced by a local bike shop, using a SRAM PC850. I had no issues shifting with the original chain; performance was crisp and I learned how to adjust it properly. The replacement chain feels like it is creeping up on the next cog at the rear derailleur then releasing. Clearances are all correct and nothing appears to be hanging up. This only happens under load, not on the stand. Again, old chain did not do this, and I did not keep the old chain (dumb move). I took the bike back and the tech ran it though the gears and stated my shifter needs replacement. Now… with cable full slack on the derailleur, and the idlers right under the smallest cog, the skipping occurs. And since is does not happen on the stand it is very hard to replicate to determine the problem. I might suspect the old chain was narrower, but I cannot see any place where it hangs up. When is “skips”, I see the derailleur extend slightly until is returns to normal position. This is on most cogs but mostly the smallest and the bike is not rideable. Any ideas?

fenix

Presumably the LBS have put the right speed chain on ?

Possibly your drive train is worn - so replacing an old chain with new can cause problems.

It may bed in slightly - but the other option would be a new cassette and chainrings if they are worn.

Personally I'd see how it goes for a few weeks.

The Rookie

I suspect a worn cassette/freewheel and its skipping.......