Chain jamming on frame

MrKawamura

My chain keeps getting jammed up between the inner chain ring and the chainstay, from the bottom. It usually happens when I change down to the small ring. I can mostly avoid it by making sure I change in good time while the cranks are still turning quickly and under no great pressure, but it still happens sometimes. The chain has scraped all the paint off the frame at the point of contact and is now digging little chunks out of the metal. This is not good!

Is anyone able to suggest how I might stop this from heppening? I thought about ftting something to the chainstay to stop the chain riding high enough to get jammed. Do you think something just needs adjusting? The bike is new, with supposedly decent SRAM components and seems to shift smoothly.

nicklouse

The bike is new

the first point of call is the supplying shop.

is the chain staying on the ring and being pulled up onto the chain stay? or is it falling of the ring and onto the bb shell?

MrKawamura

The chain is staying on the ring and being pulled up onto the chain stay. The gap between the chain stay and the inner ring is small, so the chain gets jammed, damaging the frame, and probably the chain too.

I am planning to take the bike in to the shop for its free service this week, and will ask them to help with this issue - I like to get some kind of independent understanding of the matter, which is why I'm asking for help from the good folk of this forum. Pointers much appreciated, thanks.

CraigFoster

Been having this on my new bike as well and I'm thinking about installing additional spacers on the drive train side to increase space between the chain ring and the chain stay.

tjm

this might help.... http://fagan.co.za/Bikes/Csuck/

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MrKawamura

Great, thanks for the link, that seems pretty comprehensive.