Originally posted by TryHard
Well I was using the HPI 15-40's, and the gearing I used 100 spur, 29 pinion. that works out at 7.543. Bear in mind, my motor is rated upto 30,000rpm, so that maybe off a little for lower reving motors (I think thats correct, if not someone hear will correct me)
Ed
Thanks, thats just over 26mm/rev so sounds about right. Ive got a ballpark figure to start with now when i get around to ordering an EA roar from Mr Jolly.