How does this look.

Enter Front/Rear Differential Gear Ratio:3.3076923076923075
Enter Transmission Gear Ratio:1
Enter Spur Gear tooth count:1
Enter Pinion Gear tooth count:1
Enter total battery voltage:21
Enter kv rating of brushless motor:400
Enter tire diameter in inches:5.65

For a top speed of 42.69 mph with this motor:http://www.hobbycity.com/hobbycity/s...(Eq:_4030_AXi)