Bicycle Chain Catcher

This is my chain catcher design. The idea is that if the chain were to derail and fall towards the bottom bracket and seat tube, this chain catcher will try to force it back on the chainring. If not it should keep the chain from falling to the bottom bracket causing damage. Occasionally my chain will fall this way, this happens on both my touring and road bike. When I am in the big chain ring and low rear cog and shift to a smaller front chain ring the chain will fall off. Happens rarely but when it happens it's a pain. Perhaps its my shifting style, may be I should not be in that bad gear anyway.

I have been testing this for several weeks now and have not been able to reproduce the problem. It either works or I just have not had the problem yet.

This design is held on by cable ties. In the future I may make a better looking clamp.

Fitting? I put it just up to the small chainring without rubbing on the chain. You may need to grind it off a little. If it turns out