I’ve got a 105 10spd chainset on my roadbike but I’m finding now that when I drop from the big to the small ring on the front the chain actually drops between the two rings and gets stuck. I haven’t changed the front rings in the last couple of years but the chain itself is relatively new. The front chainring bolts are tight

On my mountainbikes there is no way to get a chain between the rings so I’m a bit confused. Is there a standard spacing between chainrings I should check or any other suggestions? Otherwise I’ll just change the chaingrings and see if that fixes it

You’ve used an 11 speed chain.

mmm, I wonder. Runs off to check

nope – KMC X10EL. Was definitely a possibility though as there are at least 4 different chain sizes in my parts bin now

chainrings not clamped down onto spider properly or the inner one the correct way round?

Clamped on properly. Appear to be the correct way around in that the writing is on the outside on both. Looking at the spacing between the inside and outside teeth (eyeballing it only) it looks wider that my other 10spd bike. I can’t imagine a chainring wearing enough to do that though. Nothing looks bent either, or at least if I spin the rings I don’t see any wobble.

Time to see if the chaingring spacing in online somewhere

edit: Sheldon says it should be 5mm but it looks more like 8. Time to take the chaingrings off and see if anything is funny

plus I’ve got a glass of whisky and am not in a hurry to do anything else 🙂

editedit: oh, apart from pick up my daughter. Better find another bike….

writing should be on the inside on the inner chainring so you can see what it is without removing it or the outer one.

3mm sounds like just the right amount for a chainring to be the wrong way round.

k. I’ll check that

Like this:

The writing is on the outside, I wonder if I put it on the wrong way round last time I changed the rings. It’s possible I’ve changed them more recently than I remember.

Thanks – I’ll give that a shot but better go pick up daughter. Back in a while

and andyl is king of remote diagnosis 💡 It was indeed the inside chainring the wrong way round. Must pay more attention next time

Thanks again all