Well, my buds run 55t motors on 3s lipo, and with 2.2 tires and axial trannys geared 14/87 they get about 5mph out of them. I prefer a bit of wheel speed as I think it can be an asset when crawling. A 55t motor has a kv of about 1100, so the speed calc may be useful. On 2s figure 3.5mph with stock gearing on an ax10.