This chainkeeper system is designed to completely prevent chain derailments and jamming on Challenge bikes with a 19T/40mm bearing power side idler (Fujin, Furai, Mistral, newer Hurricanes, etc.). The chain is guided onto and controlled past the idler with a carefully designed plastic chute. This way, the chain is controlled in all directions as it approaches and goes over the idler. There is nowhere for the chain to go except for where it is supposed to go.
If you are having problems with chain derailment, jamming, and bent chainkeepers on your Challenge bike, this is the solution.
The kit comes with two stainless steel mounting arms, one for each of the two Challenge mounting types. The first has a 40mm ID round hole, for bikes like the Mistral and the newer suspended Hurricanes, etc. where the idler mount is part of the suspension pivot. The second arm has an 8mm square hole in it to match the square section on the back of the 5 pointed star idler mounts on things like the Fujin and the Furai. An adjustable chaintube mounting arm is also provided in case you want to run a full length chaintube on the power side chain. This can be removed if you use something like our Fujin/Furai Return Idler kits, since they move the mid return idler down out of the way of the power side chain and provide a floating chaintube to protect the fork.
Very good reviews from our riders.