Gearbox help

[Saberwing40k]

Okay, so i'm building a large trial truck, and i want it to have a remote control gearbox. only problem is, i also want it to have 4 xl motors for propulsion. i'm looking for a gearbox that:

• has at least 4 speeds
  
• is tough enough to withstand the power of 4 xl motors being crammed through it. (or just being in a truck.)
  
• is easy to remote control with only one motor
  

currently, i have a modified version of Sariel's 4 speed linear gearbox, and a shifting mechanism. only problem is that that is bulky and hard to mount.

Any ideas?

thanks in advance!

[timslegos]

[*]is tough enough to withstand the power of 4 xl motors being crammed through it. (or just being in a truck.)

Lego axles start to bend with the force of only 2 xl motors attached to them so i think 4 xl's will destroy the axles and gears.

tim

[allanp]

If you can power them, I think you wold be better using 4 buggy motors. They produce about the same mechnicle power as XL motors when geared down to the same speed, but you can also have your gearbox just after the motors, before that gearing down so you can transmit more power though the gearbox by having it spin much faster with the gearing down you need after the gearbox. With that you can use many of the more conventional 4 speed gearboxes already used in many MOCs.

[Saberwing40k]

If you can power them, I think you wold be better using 4 buggy motors. They produce about the same mechnicle power as XL motors when geared down to the same speed, but you can also have your gearbox just after the motors, before that gearing down so you can transmit more power though the gearbox by having it spin much faster with the gearing down you need after the gearbox. With that you can use many of the more conventional 4 speed gearboxes already used in many MOCs.

no, buggy motors are not more powerful, at least going by philo's comparative sheet. they are also less efficient, and i don't have any. and how would you hook 4 buggy motors to one regular gearbox and not have it be destroyed by the speed?

[Sam42]

Buggy motors would be unsuitable I feel, the higher rpm of the output would require more gearing down in the transmission which would in turn give the associated losses.

My first suggestion would be something strong and simple like sariels simple two speed heavy-duty linear box

http://sariel.pl/2011/02/2-speed-heavy-duty-linear-gearbox/

I would question the need for 4 XL motors though, some of the largest competitors in last year's lugpol tt used only 1! With 4 XL motors you'll definately break some gears!

This is what 2 xls can do when used with wreckless abandon!

truck trial kills parts! by sam2442, on Flickr