Okay, GRU lovers need motor advice!
 

Anyone running a cheap 19t, 20t, or 21t can with the GRU?


Looking for the GRU grunt, more speed, and the ability of the GRU to act as a drag brake.


Thanks8)

Gru?

The HPI Gear Reduction Unit.

If its the Glavnoye Razvedyvatel'noye Upravleniye, we are in trouble.

Running the stock 27t motor in mine. Works fine. I dont know that I'd go much lower turns-wise, the 27 works fine and the gearbox internals do not have bearings so you'd just be wearing things out with more RPM's. Use the pinion to gear up a bit if more speed is needed. the HPI GRU is SLOW, I bumped up a few teeth on the pinion.

Gru
 

I also run the stock motor with the gru. Its acts like a drag brake and gear up for speed

run the planetary type. it works good. rc4wd disruptor, tamiya cr01....

I want a brake on my trail truck. I have a 35t RC4WD can, and a Traxxas XL-5 esc. I am just wondering if anyone has gone down to 20ish, and what the speed is like.

BTW: the GRU does have bearings.

Re: Okay, GRU lovers need motor advice!
 

I know this is a little late, but I am just now reading this and just did this mod. We just put a 20t scorpion traxxas motor on my brothers ck that had an hpi 55t and GRU...way too slow. The 20t is nice, I have the 27t saturn and gru and will purchasing a 20t.

The gru only has one or two small bearings inside, also the ck has all stock gears. One final note, the I had to cut the shaft on the traxxas motor to bale to use it on the GRU. I just referenced the length on the saturn motor.

Hope this helps.

Re: Okay, GRU lovers need motor advice!
 

If you're doing all this motor swapping anyway why not just ditch the GRU and buy a 35,45 or 55 turn?