Originally Posted by
walshconor
So I recently got my old 105 components put on a new frame. Got back from the shop and put the bike on the trainer for a short ride. To my dismay when I shifted from the big ring to the small ring (while in one of the smallest rear cogs) the chain did not engage on the small ring teeth and instead just slid on top of them. This doesnt seem to happen when Im in a large cog in the rear. Did they put a 10 speed chain on my 9 speed bike? What going on?
Thanks for any help.
The 5600 is a 105-level 10 speed chain, but I don't think that's the problem. The differences in the width of the chain allow it to better fit between rear cogs and to flex better around the newer front cranks that have a slight spacing difference, but I've never seen it affect how the chain sits on the cog once the gear is aligned properly. Normally you can even put a 9 speed chain on a 10 speed bike and it will work but just catch on the sides of the chainrings and cogs a bit.
What you're describing sounds more like the shop messed up the front indexing or front derailleur alignment somehow. Does the chain slide on top of the chainring when it is centered, or does it sort of sit on one side or the other?