well if your stripping spur gears that consistently then one of a few things is going on.
either your slipper is too tight, your motor mount screws are not tight enough/not biting in, or your mesh isnt any good.
it may be one of those, it may be a combination of them.
when you play with gearing, for the most part, you gear for temps, not for speed. though some gearing changes can be part of the setup process. in bashing though its all about temperature control.
Florida Oval Racer | Vintage traxxas collector | Mad Scientist