My Mad Emaxx 3905 Vtwin Video

[lincpimp]

Originally Posted by Serum

that's not 55 mph? i guess 40-45 mph tops.

He can't be far off, unless the motor kv is way off spec, or the lipo voltage is really sagging under load. Check out the speed calc:

Differential Ratio: 2.8461538461538462
Transmission Ratio: 1.83
Spur Tooth Count: 65
Pinion Tooth Count: 22
Total Voltage: 11.1
Motor KV: 3500
Tire Diameter (inches): 7
Total Motor Speed: 38850 RPM
Vehicle Speed: 52.57 MPH

You have to factor wind resistance, but I did not account for tire ballooning, so he is most likely near 50 if not more. I find brian's speed calc to be quite accurate and that the tire expansion usually takes care of wind resistance, at least up to 70mph or so (I just leave the ballooninng section black). I always gear according to the speed calc and then check with my radar gun. Never more than 2-3mph off. My tamiya was actually almost dead on, but it has foam tires and a slippery body.