30mph? How?

[MetalMan]

If the motor was running at a good temperature (indicating proper gearing), my best guess would be that because radar guns are made for real cars, the radar gun couldn't get good enough contact with the E-Maxx to give an accurate reading.

EDIT:
I just read that you said that with the spreadsheet your speed came out to 29.11mph. There has got to be something going on with your gearing. Go up a few teeth on the pinion, and that should do it.