Originally Posted by
tc5basher
Here's the issue: The cup racer uses a "ring" which you bolt to the motor.
According to HPI the smallest pinion you can use is a 25 tooth. The available spur gears are 65 and 67 only! Castle reccomends a 18 tooth pinion for my set up, but it won't mesh with such a small spur. You need more like a 87 tooth spur gear. So in order to go brushless i am stuck with a Noval or LRP setup, which is ok, but I need to figure out which motor will work best using a65 tooth spur and any pinion form 25 tooth to 39 tooth.
I really am leanig toward the Novak Havoc system becuase of price (its $80 cheaper). So the real question is which motor to get 21.5,17.5,15,13.5 or?
Who at Castle recommended the 18T? That is quite a significant jump from the stock 30T pinion. Did the Castle rep factor in the smaller diameter wheels of the Cup Racer?
Honestly, I think you will be fine with a 25T pinion. When I ran my 5700kv in my other car, I only geared down a couple of teeth. Motor, ESC, and battery temps were all fine.