My esc keeps overheating on me reaching the thermal protection limit after about 7 min run time.

I am running the rx8 gen 2 in my sc10 4x4 with a tekin 7.5 gen 2 also. 12guage wiring 2 cell lipo battery's I think 60c.

I've messed with the gearing even though the motor temps are below 160 and nothing changed. I've tried changing the motor to a reedy 4.5 that I have too but nothing. The gear mesh is perfect and smooth as butter. When I first bought it used there was a binding issue in the drivetrain but I've fixed it and have gone through it 3 more times thinking its a binding thing but it can't be.

My next thought is not a cheap one but am I running the wrong motors type? Do I have to run stuff like the pro4hd motor specifically cause I have a 4x4?

Thx in advance for your help guys.

There's a lot of drag and loss in the drivetrain on that truck, I'd stay with the 7.5 turn and if the motors running cool try go up 1 or 2 teeth on the pinion. You could be under geared, that usually creates a cooler motor and hot esc.

Are you hitting low voltage cut off? Does this happen around 10 minutes? Edit... reading skills lol.
If it is happening at about 7 minutes your lipo may be done for that run. What lights are going on the esc?

You can run 2 pole motors but a 4 pole (of any brand or model) is definitely a better match for a 4x sct.

Are you getting the motor temp from the data logs or another way?

on the sc10 4x4, I found that either a 4000kv or 4600kv motor worked well on 2S. You have to also keep in mind your available gearing range with that vehicle too.

Few questions:

- what is your gearing that used on the 7.5 and the 4.5?
- where are you topping out down the longest straight?
- how tight do you have your belt?
- with everything dissengaged from the drivetrain (ex- no pinion on motor) how well does your vehicle free roll?

Wow thx for all these replies guys.

As for the gearing I was at a 15 tooth then went to 13 and now am at a 11 on the pinion. I've kept the spur stock for now.


As for the voltage cut off its not that when it shuts down I immediately take the body off and it shows the temp is maxed out. There's a different flash sequence for the low voltage.
When I check the motor temp I'm using a nitro temp gun at the middle side of the can. I haven't figured out how to do any logging yet I tried for a minute but didn't see it.

I have loosened the belt a lot I do think it was too tight in the beginning. I'm not a fan of the belt system I feel there is drag there. With the belt off and pinion off it rolls like nothing so easy but there is some drag with the belt on. I can't wait for the new associated 4x4 to come out.

Cain will remember the gearing for that truck, I forgot, it's been a few years.
I think 17 - 18 was good gearing for a 4600kv, from memory that translates to 5.5t or something like that. So you may just be under geared. Could be totally off on tooth count, cain or someone that remembers that truck will chime in.

Like cain said, you can't run the belt too tight. Issue may be coming from there too.

There are many other great trucks, the tekno, losi and the new durango (haven't driven but looks like a great truck). Not sure I'd wait... ae's attempts so far were/are way behind the class leaders.

from what I recall, with a 4000kv motor I found that the sc10 4x4 kind of had a sweet spot of gearing that it could pull before it would get hot. It was as if your normal gearing method on say a tekno, etc wouldn't work on the sc10 4x4.

I ended up going I think about a 13 or 14T pinion, but then using boost as the higher RPM ranges to get top speed. this allowed the electronics to run cooler versus going to what I thought was a more appropriate larger pinion size. And this was only 5 degrees max of boost.

One other thing is that the Sc10 4x4 depending on how you have your electronics laid out can cause heat issues with ESCs and especially motors.

Personally if you were using your gearing with that 7.5T motor I woudl say you were way under geared. with a 4.5 that gearing you said seems closer to what I recall.

For the gearing there is a chart in the booklet that I did follow there's a few options. I can't remember exactly what it said now I'll try to post a pic of it if we need it.

I don't like how noisy the techno is here at my local track I swear he's going to loose his gears but he runs it like that every time I'm at the track and it works.

It is louder, heard a electric 1/8 buggy? Pretty much the same drivetrain, bomb proof with 1/10 power.
If it is loud loud though his may just need maintenance or propper lash in the gears because they aren't crazy loud... unless he is using the metal spur gear.

I drove your truck for about a year so I know it well. Ask the tekno guy for a couple laps with it

lol. yeah coming from a SC10 4x4 the noise will be quite a shock. However, so will how much better your driving experience with the Tekno.

Ok thx a lot guys. I had an Novak ballistics 4.5 motor and just tried it. It ran for almost 20 min. Motor temp stayed at about 160 and I did check the esc temp on the lights from time to time and it stayed in the middle which I think is great. Only stopped running cause the screw came out of the servo horn. I don't like this motor much it feels like a beast not the snappy motor I had

yeah I preferred the torque a 540 4 pole offered in comparison to the 550 2 pole I had.

Did you modify the Rx8 case? Are you running a fan? If you're running the fan there's no way you're thermalling the Rx8 with a 7.5.

I'd wager either the fan isn't working, or something else is wrong here. Pictures please?

is there a power cap for a rx8 esc from tekin dint see it in the paper work is there one mounted to the battery post

The RX8 does not use an external power cap.