Thanks! the Caterpillar doesn't handle too well, tires are rubbing on the body a little, have to tweak it a bit
How does the A-Team mobile handle? do you have to wear gold jewelry before driving it?
You should be fine running the 20T pinion with a 21turn ... just be careful with the gears, maybe put some grease or teflon spray on them, if you run them dry with anything more than a sport tuned motor then they are more likely to melt/strip. I've run mine with a 12T motor ... very fast, but if I hit the brakes really hard it will sometimes strip the gears, so it's better to be easy on the brake and the throttle