Hot motors!! help

[panama]

I have a tech question. I have a Brxl and running
3s and 4s. on a 35t cheapy and burned up. to far advanced timing . learned a lesson" leave timing alone"
The esc is in a scx10 I replaced the cheapy with a 16t hand wound crawlmaster . I ve sent it back to HH burned up. i payed for a rebuild and hope its still ok to rebuild. I did not read the very top line on the crawlmaster page to "only use a 16t pinion" I was working my way down to it from a 19t. when it burned., Any way i bought a 21t torque master from a fella here. I put a 16t pinion on it and test ran it. Its getting pretty hot 177
and would have went higher. but ran for a good 15 minutes mildly hard. it was very fast on 4s and 16/87
should i keep dropping pin teeth to a 12t or ??? does the weight of the mip drive shafts affect the heat.
My wifes scx10 has a 35t cheapy with a 26t pinion that runns great and never gets hot i dont get it. the motor is the same kind mine burned up. with timing out of wak. hers i adjusted to maybe retarde timing 2-3degrees. HUH? thanks for any help

[TNT1]

What else different in the 2 trucks?Compare the 2, is your drivetrain binding?I have MIP's in my dingo wheelbase scx10 and i've noticed they bottom out and bind on full articulation if there is no limiters in the shocks.

[05Fronty4x]

Maybe stick to 2s or 3s. If you run anything higher than 2s make sure the motors are rated for it, and reduce your pinion size accordingly. Nothing will kill a motor faster than too much voltage and incorrect gearing. If I were even ballsy enough to try 4s I would put the smallest pinion I could find on it (and I don't know that there is one small enough to get the right gear ratio for a 21T motor on 4s). Even on 3s I would run the smallest pinion possible on a 21T.

Just for a tiny sliver of reference, I'm running a 55T on 3s with 18/87 gearing on 4.6" tall tires with no heat issues. I'd venture to say a 21T produces something like 3 times (maybe even more) the RPM per volt as my 55T does meaning I'd need a 6 tooth pinion (lol) for equal wheel speed.

[panama]

Thanks TNT and Fronty. Now that I'm playin with bigger bats w/ the Brxl, I see I need to look in to the motor volt limit EH?
I was thinking maybe a 45t motor. I like wheel turn speed with torque. a lot of sand hills and clay rock crawlin but climbing hills I like to be able spinn the tires and not bog down.
Power. SO how is the 55t for trail bashin. under a load does it perform well. Does it digg hard and not give up?
I really need to get this right for my "Wreck" build. It will have a Brxl. and its heavy. I have a thread to the beginning build of it in 2.2 scale section. It's gonna be wide with the Ar60 axles and a chopped top for a better lcg. i dont want to be taking the motor or pinion out all the time. Thanks for the heads up on the info.

[05Fronty4x]

A 55T is great for what it is, but even on 3s it is not fast by any means...definitely some crazy low end torque though. If I were to go on a hike or extended trail run I'd probably toss in a 27T just because I have a variety of them from my on-road racing days, but I generally keep things pretty slow and 3s with a 55T gives plenty of wheelspeed for my style.

Sounds to me like something in the 35T range running on 3s should suit you pretty well, but don't expect the speed you've been getting out of the 16 and 21T (then again, you are overworking them). I've seen others say their 35T's rip on 3s, and geared properly should be a great balance of low end grunt, wheel speed and longevity. Your current low turn motor + high voltage outings will continue to result in very often maintenance to keep things up to speed. If you stay out of mud and water I'd consider a brushless setup since it seems you run your rigs pretty hard. They will handle the abuse with less maintenance.

The main thing I would do at this point would be to get ahold of Holmes so you can make the best use of your current brushed motors. I don't know what kind of voltage those motors can handle, but gearing plays a huge role. I probably wouldn't run that 16T on anything higher than 2s and would only run the 21T on 3s with a really small pinion. 4s with either of them seems out of the question unless you want to rebuild them after every run. That being said, Holmes knows his motors best, and I'd get the info from him.

[indiana mudcat]

Realize his 16 and 20 are five slots equal to 35's and 45's.

Gear down, check for binding.

[05Fronty4x]

Originally Posted by indiana mudcat

Realize his 16 and 20 are five slots equal to 35's and 45's.

Gear down, check for binding.

Didn't think about that. Good looking out. A 16 tooth sounds about right on 3s, I still don't know about running 4s though.

[panama]

no brushed on 4s ---- I SEE said the blind one. thanks for the help folks. holmes is helping me now with a setup.