Hey all, I ride a 26" stretch cruiser (its about 8 feet long) and I'm having a little trouble with my chain. The damn thing is so long that frequently when i go over bumps the chain comes off the back sprocket (its a 3 speed in the hub, no derailleur).

The rear wheel is set back as far as I can physically get it in the dropouts. and there's still probably 3/4" further I could go but like i said thats as far out as I'm physically able to move it and the chain still pops off.

I'm wondering if there's a chain tensioning device that i could use to help prevent the chain from popping off, I've looked around but everything I find seems to be made to convert a frame with a Derailleur to a single speed. Will that work even though thats not what i'm doing?