I keep destroying cranks. I’ve only been unicycling since September, but I’ve trashed 3 pairs of cranks in that time. The problem seems to be my right pedal starts to get a little loose and it strips the threads. I keep checking to make sure it is on tight before I ride, but the other day I was riding for a long time, I felt a little wiggle in the pedal, I stopped, and the threads are dead. If anyone has had this problem, please help me solve it.
the pedals might be on the wrong side? idk:p
This should not happen.
You must have the left crank and pedal on the left side of the uni, and the right crank and pedal on the right side of the uni.
The right-side pedal has a normal thread - clockwise to tighten. The left-side pedal should have a left handed thread - anticlockwise 9counterclockwise) to tighten.
If they are on the correct sides, the riding action will tend to tighten them. if they are on the wrong sides, then can unwind within a few hundred metres - or even less.
Hey. You.
Move it over to Rec.Sport, where you’ll get the attention you deserve!!! 
:o
You’re probably making one out of two mistakes.
You’re either: Not putting the right crank and right pedal is on the right ride and the left on the left. The pedal will start to unscrew, and this will destroy the threads.
OR
You’re crossthreading the pedals. Right pedals go on normally (righty-tighty, left-loosey) The left pedals go on the other way. I put a dab of oil on the threads before I put the pedals on, then screw them on the first few revolutions using only my fingers. If you have to use force, you’re probably crossthreading them which pretty much destroys them. They might seem tight at first, but after a bit of riding, the threads will fall apart.
It sounds like it might be your pedals. If you’ve screwed up the thread on the pedals then it’ll probably screw up the thread in the cranks.
I’d go to my lbs and get them to check it out, but I think your problem is your pedals.