As others have already said I like to drive my tanks slowly-even the KV with stock metal gearing can be driven realistically, with care. Something worthbearing in mindis that we are seldom in a position to drive in a scale landscape-that gravelsurface scales up to boulders a couple of feet across!
I'm picky where I run them too; no water, sand or mud and dry, firm surfaces only so nothing is over-stressed.