Originally Posted by Steve420

I'm just waiting for my EzRun 35A / 13T combo to arrive, but was wondering about what pinion size I should use.
It looks like the M04 only lets me run a 17T, 20T or 21T pinion. A 17T came with my kit, so I was just planning on using that one. Will the 17T be okay?

And what size (teeth wise) is the Spur? And is there anyway to change out the spur size? Since it seems to be built into the gear box, I would guess that answer is No, but figured I'd check anyway.