I'm looking for some ideas on fabricating something to keep my son's chain from popping off his chainring. He rides a KMX Cyclone which does not have a front derailleur. I had the original front ring replaced last summer in an effort to expand the trike's limited gear range. It didn't work as I'd hoped and now the chain pops off. The chain does not appear to be too loose, but does tend to pop off the ring with annoying regularity. I'm thinking of fabricating something out of a cannibalized front derailleur cage that would fit over the chain to help hold it in place. I am thinking that a simple hose clamp around the bottom bracket could be used to hold an L-shaped metal arm parallel to the chainring. The derailleur cage could then be attached to this arm, much as it would be normally placed on a trike with a double or triple ring. This, however, would be stationary rather than moveable. Does this sound plausible or does anyone have any other suggestions?

Patti

I have seen on other boards passing a chain through a piece of garden hose that was positioned in a fashion to that it would align itself for the chain to pass over the sprockets.

Bill

One thing that might cause the chain to pop off if there is a link that doesn’t function well. Next time it falls off test each link to see if it bends easily also sideways. Sometimes one link will not bend easily sideways and force the chain off. If you find a bad link you can try to straighten it or just replace the chain.

Peder

Most likely there is a tight or bent link. If you can, take off the chain and slowly pull it over your index finger as it hangs. You will find the problem!