[Candyman]

2050kv motor on 4s, with 130mm tyres, 4.5:1 gear ratio (45 ring 10 pinion) and a 48 spur gives you.........

17 pinion would give top speed of 36.6 mph
18 pinion 38.7mph
19 pinion 40.9 mph
20 pinion 43 mph