Chain Slipping
 

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.

Start by telling us what chain they put on followed by the model, if written on the chain itself (e.g shimano 6600).

new cables? could be cable stretch.
dunno why you'd question the chain first.

I just looked at the bill and the chain is listed as a Shimano SH CN-5600. I believe this is a ten speed chain....

It's best to not cross-chain that much but if the chainline is good you probably should be able to make this shift.

If this chain skating is happening on the trainer but not on the road I wouldn't change anything. A bike frame flexes laterally more on a trainer than on the groung because the rear wheel is locked on the trainer. If it's happening on the road and if you have a conventional bottom bracket you could use a 2 mm bb spacer to move the chainline out. Or just try a 9-speed chain.

Al

This is correct.

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?

Worn chainrings can also cause this problem.

+1 on helicomatic. If the original chain was worn to much the new chain will not match up correctly with the cassette.