Kurt Kinetic Trainer

I've been riding my trainer a lot lately, a Kurt Kinetic Road Machine, and I will say first that I think it's a great piece of equipment. However, I've had an issue with it the past few days: the knob has been very difficult to tighten and loosen, to the point that I can't tighten it the full two turns the manual recommends. After I ride it, I always unscrew the adjustment knob so that there's no contact between the tire and the roller. When I tighten it back up the next time, I only go the two turns that the manual recommends.

Last night, I unscrewed the adjustment knob all the way out and pulled the L-bolt out. The internal threads inside the knob looked OK, but there was a fair bit of damage to the threads on the L-bolt (the dark area in the picture).


Today, I ran a die over the L-bolt and it seemed to clean up most of the damaged threads. I also ran a tap through the knob, although I'm not sure this was necessary. I cleaned both parts thoroughly and now they go together very smoothly. I also put a little grease on the threads before I put everything back together on the trainer. It won't help with the thread damage, but it should keep things turning smoothly.

So, why did this happen? Well, one way or another, that threaded joint got overstressed. Maybe I overtightened it, but I don't think that would do it alone. I think that maybe my rear wheel is out of true enough so that it overloads the joint every time the high spot comes around. Until I have time to true the wheel, I'm just going to make sure that I tighten the adjustment knob when the wheel's high spot is against the roller. It may result in some tire slippage, but that's better than continuing to trash my trainer.