Hi ^^

I want to build 6x6 (first axle steering) trial uphill truck (outdoor fun in mountain) and i have two question.

Tyres used: 107x44 (15038)

Estimated weight: 2.5kg

1. Engine used

I have 3x XL motor, and i think how design drive train:

1. 2 or 3 motors drive all wheels (like normal car)
2. 1 motor to front axle 2 motors to rear both axles
3. 1 motor per axle

Which will be the most effective?

2. Gearing

I don't wanna use any gearbox, and i think about 3:1 or 5:1 (or maybee less could be too?)

 

Thanks for help 

 

There are some great examples out there, starting with this:

https://rebrickable.com/mocs/MOC-27092/Madoca1977/tatra-t813-8x8-profa/#comments

I'd consider using one motor per axle. This way you should have fewer frictional losses and you don't need centre differentials.

It'll be slow with XL motors or need a lot of gearing up. Gearing up 3:1 likely means using an 8 tooth gear in there, which is certainly risky, or you need a few of the expensive 36t gears. Maybe you can put two motors either side of a 5*7 frame with a 36t on each, and 12t gears at each end going to the rear axles. And a third on its own for the front?

Sadly i don't have 36T :( .

 

Yes i planned use 8T but it like to destroy yes ? I could use T12 with T20 and get ~ 1.667:1 but it could be not enough to move uphill...

I wouldn't want to rely on XL motors driving 8t gears. It's bound to kill them. For the same reason you may want to build it with locked differentials as the 12t gears can pop out the diffs under high stress.

k