I have a Rc8.2e with stock spur gear and a tekin rx8 with a tekin 1900kv motor, what would be a good pinion gear size for a large track

Deos the Rc8E use the same gears as the nitro. I think the nitro uses a 16 tooth bell.

So I'd put a 17,18, and 19 in my pit box since the 1900 has a bit less RPM than a nitro engine.

Delete please. Sorry.

Start with 18 for the 1900. If your motor gets to hot move up to 19.

How does that make sense? Wouldn't a motor get hot if it was overgeared?
I know they can get hot from being undergeared but you almost need to run full throttle for a long time for that to be the case.

+1

I run a 2050 in mine and after a 10 minute main with an 18t my motor temps were around 165. Switched to a 19t and they dropped to 150 after mains. Esc remained the same temperature. Im just speaking from experience i've had with mine..

Hmmmm! 18 t 165 then switched to 19 t went to 150 ? Maybe it's the other way around bro. Over gearing will brink the temp up or it could be that your on the throttle thereby reducing temp..

These are 3 phase motors that the ESC has to fire the right phase at the right moment. If you're under geared the ESC may not be able to keep up and timing gets screw'd up. Just my theory, not sure if true, just seems like brushless setups have a hard enough job allready, undergeared has to suck.

I've seen similar things happen to VFD drives.

But a motor geared proper will run cooler than 2 teeth low (in 1/8th scale). And 19t is not over geared at all.

1900=31,920 rpm
Nitro engine is 35,000-40,000 rpm.

RC8 nitro is geared with a 16t bell. So a 19 or 20t pinion may be the hot ticket. In my lighter 808E 20t is perfect.

I have had similar experience with a 1400 t8 on 6s. Longer run times too with the more tooth gears. Needs a lota patience and testing temps to figure out each track and gearing.

I want one