Took a ~40 mile ride this weekend, and wound up stripping the splines on both the crank and the jammer. Correction to my earlier post, my gearing is 27 front 28 rear. I believe my gearing was too aggressive. Not sure if I'll be able to run the jammer on a new crank or not but I'm going to try. Kind of sucks I got less than 100 miles out of it.