(Hoese37)--Only the rims are vented currently...

(ElectricMann)--I'll check for the wheel hubs are rubbing but I dont think the hubs pass the hex adapters. Its possible the hex adapters are rubbing but I think I would have shredded a bearing by now if that was happening.

(kiwi_Tim)--I have been running right and left tires...not swapping them from side to side. So its possible thats causing the one to balloon more than the other.