Our team had similar issues. Unfortunately, we didn't get to test the wheels until the Midwest regional, so when the treads came off, we got penalties.
Our temporary solution for the day was to ziptie through the holes we drilled in the tread. Seeing that this wouldn't hold for very long, we looked around for a better way to keep the tread on. We hit upon the bolts that held in our 5" traction wheels which only were used when we went over the bump.
The next day, we came in with several round-head bolts and nylocks to fit them; we never had another problem with those treads.