So my Cannondale toured has a mix of 10spd 105 and 10spd XT components and a fault that I just can’t trace.
In the granny ring then ever so often then chain hooks up and the derailleur comes forward and the drive train locks.
This doesn’t happen in the middle or big ring.
I’ve checked the chain length and taken an extra link out, reset all the mech settings B screw makes no odds.
I thought the cassette was loose so stripped and tightened.
I’ve also swapped out all the front rings.
I’m lost. I don’t see what else it can be.
Chain suck?
The inner ring might have a misshapen tooth, or a burr.
EDIT: I don't think that's what you're describing actually.
I reckon that when the chain is under load on the granny ring it is unable to release from the teeth of the granny ring? 🤔
How many teeth on the granny ring? So you have a bigger granny ring? Or could you shave the tips of the teeth off so that there is less chance of the chain remaining on the granny ring?
This is my guess work and probably an incorrect answer. But if it was my set up I'd probably get a file out and knock the tops off the granny ring.
I wondered that, hence swapping out the rings.
EDIT: I don't think that's what you're describing actually.
I think it is what is being described.
Next solution apart from my file suggestion is to remove the granny ring and just run a double up front!
Small rings always seem to have big teeth compared to the size of the ring. Is it a 20tooth ring?
Or an old 28/38/48 , or 22/32/42
When you swapped the front rings, did you replace the chain too? This kind of fault is often to do with components that are worn to different extents and don't mesh together properly.
It’s 22 or 24 I think
As tthew says, if you’ve changed the rings it points to the chain. What you’ve described sounds like chain suck. This could be caused by a worn or damaged chain or a stiff link.
Ok! New chain time it is 🙂
You don't say if the swapped rings are new or if the chain is new. As above if the ring is even slightly worn file any hooks off the ring and reduce the height of the teeth slightly. If the granny ring isn't new try it inside out, it'll be poorly spaced but if it runs ok that tells you it's the source of the problem.