RE: Is 4 lbs. to heavy for a 1/10th scale car???
I went and bought a brand new Integy tire lathe to cut the tires down. In fact, the place that I got the tire lathe from races at a local track and they are the ones that gave me the tire measurements to cut down to and showed me their very own Mugen tires that were cut. I took .078 off the rears and .072 off the fronts. Just as a test as you mentioned Ziggy, I have several sets of these tires and did try another set of 1/8th fronts/rear and there was no change in the way my diff was acting/working. The car handles just fine with the large tires in the rear and the smaller ones in the front. That has not been the case this time. It was the differential slipping the ring gear. That is now fixed as I took the car out last night and it is not shaking the front tires anymore at all.