I am curious to hear the results of Mark’s testing of the rear side-to-side weight balance on the RevoSlot car to see what difference it makes on the increased wear to the rear tires on the left side of the car. There is a difference in rear weight left-to-right but I suspect it may not be the cause of the difference in wear. I think it may have more to do with driver technique and the layout of the track. The RevoSlot cars are heavy and increased wear can be expected. I think it may be that drivers may generally drive harder through the turns on the north end of the track, putting more wear on the left side. It could be, though, that weight balance is a factor.
In any case, it would appear that, at least, changing the rear tires left to right between races would be recommended. Measuring diameter and truing the larger tire would be an even better idea. I did not check my rear tires before the race, and only after the race did I discover that my left tire was 20.49mm and the right tire was 20.68mm. The car was unstable during the race, wriggling from side to side. The differential in gearing between the rear tires was undoubtedly the cause.