Hi all,

I am thinking of going with a single ring up front and I am wondering how to size the chain guard on the outside of the crank. If you run a 38 tooth chain ring, do you use a 38 tooth chain guard? Is it better to oversize, say a 38 tooth ring and a 40 tooth guard?

Thanks for the help,

Rgds,

Marley

The chain guards are larger on the inside and out side of the chain ring so if you are going to use chainrings as a chainguard then I'd get a 42 for the out side.

If you have a 38t ring get a 38t guard. The chain ring guards are larger than the rings and are sized so that they stick proud of the ring and the chain by a few mm. If you are running a single ring in front, gears in back and try to run oversized guards (inside and outside to keep the chain from bouncing) off you might get chain rub or frame interference.

If you're just going to use one on the outside, then I would recommend a 42t chainguard. It won't interfere with a 38t ring, and you can put a larger ring on in the future. My bike is currently setup with a Spot 42t chainguard and a 38t ring, and it works fine.