Qsilver7 - I'm still looking for an understanding as to why these bearings/gears (A) can't handle continuous rotation under load.
But, to address your 3% tolerance guidance, I'm looking at a set of 275/45 R20 (diameter 29.7") front and 295/45 R20 (diameter 30.5") rear.
30.5 - 29.7 = .8". I could divide the fronts or the rears by this difference. But let's go with the fronts for the highest percentage. .8/29.7 = .026936 or 2.7%. Would you anticipate troubles with this setup?