Custom gearbox?

[carcueza]

Hello. I´m thinking about build my own gearbox, but I don´t understand why everybody use XR gears.
If you use 2 unit of XR gears 12/36, the 36 gear for the shaft (from XR) and a pinion of 12T you get a reduction of 27:1.
But new with the stock tranny from axial I get a reducction of 18.6:1 (2.6:1 from the tranny and a 7.1:1 from the pinion and the 86 spur).
So, with these XR pinions we have a bigger reduction than with the stock tranny.
Are my numerical operations correct? Or am I doing some thing wrong?

Thank you!!

[filotr14lsdude]

Reduction In gears gives greater torque
Match this torque with a higher speed motor and you have a really good combination for crawling.

[carcueza]

Ok, you are right. But now I have another question...What motor could I need for this kind of gearbox?

Thank you.

[filotr14lsdude]

I've used 2 of the hulksta transmissions

Both have been with 30t motors. Both have great wheel speed on the ax10 platform.

Using a 18-20t pinion

[ned72]

Also consider when xr gears (or similar ) are used, there is no more big fat spur gear anymore.

[josh6575]

Gotta love a space saver. Who doesn't have a set of stock XR gears laying around. Sure can't use them in an xr for long.