Hey guys. I'm slowly putting togethere an electric touring car for the 17.5T class, I'm using a HiTec HS-5565MH servo. Anybody which servo horn I use? 23T/24T/25T? And for the pinion? It's an 84T spur. I'm basically a newbie when it come to skill level.
Thank you very much for the help
24 spline for the servo or it may also be marked HT
Hey guys. I'm trying to figure out what tooth count pinion I'll need, the spur gear is an 84 tooth 48P and I'll be running a 17.5T motor.
Thanks,
Clay
It depends on your internal gear ratio. I think I am running a final drive ratio of 4.2-3.8 so with my 96 spur I am somewhere between 44-49 pinion (considering the internal ratio of my XRay). But i dont race electric much so I am not an expert.....
It looks like the Serpent S411 internal gear ratio is 2.0 based on a quick online search.
You will want an overall final drive ratio (FDR) of 4.2 to start with a 17.5 motor (this will change with a 21.5)
Basic formula:
FDR = (Spur / Pinion) * Internal Gear Ratio
Rearranged to find pinion:
Pinion = (Spur * Internal Gear Ratio) / FDR
Pinion = (84 * 2.0) / 4.2
Pinion = 40
So a 40 tooth pinion should be a good starting point.
I hope that helps,
Blake