AndyCW

Thanks for the input. A slight variant of your gearbox fits perfectly between the framerails of the truck. The penalties from the inclusion of a differential outweigh the penalties of directly coupling the motors together.

On the first iteration of my truck I had a diferential in the axle, but did not have any hub reduction. It ate a couple of spider gears. I eliminated the differentials and the problem is solved. Watching the trial truck tips is what led me to get rid of the differential. Will the spider(12t) gears survive if installed after a 3:1 reduction? I see several designs where people are directly connecting the ouput of multiple pF motors. Sariel even had his double xl gear box like this. I was under the impression that chaining motors together in this manner was not good for them. If one motor is weaker than the other(due to manufacturing tolerances) it will create some load on the stronger motor, but if they are connected utilizing a diferential** this can be worked around. **which would be as far away from the axles and the majority of the loads

With you links so close together in the vertical plane they are not very able to resist the torque reaction of the axle. There are 4 studs between my upper and lower control arms and I still get some caster change between power on and power off. If you can get that pneumatic locker to work and be robust I may have to borrow that idea.

Thanks. I just finished putting Sariel's two motor transmission together and need to figure out how to mount it in the chasis. As well as whether or not I like the gear ratios it has and what I should change them to. The axles allready have 8.3:1 in them and are connected to power puller tires. Is there any advise for specific gear ratios that other people have used.

Thanks for the gearbox idea. Are there any concerns with directly connecting the output of two PF motors together or should they be connected with a differential to allow for differences in their speeds?

http://www.brickshelf.com/cgi-bin/gallery.cgi?f=463513 I just posted some pics of my WIP. I did the axles, suspension, and frame first and am now working on the powerplant/drive line. I tested it out with two med PF geared down greatly and it would not break any of the axle components. It climbed up a vertical surface and articulated to almost a 90 degree diference between front and rear axles. It doesn't have ackerman or any differentials so it is a little rough on hard surfaces. The two med PF when geared down made the truck too slow so hopefully the two xl will need less gearing and therefore make it fatser. I am working on a double xl PF with a two speed transmission (shifted by med PF) that also fits inside the box I haxe designed myself into. Hopefully it won't eat gears, axles, or joints when the power is increased. The body clips onto the frame with a couple of red pins. The battery box is part of the body structure. It still needs to go on a diet and lose some unneeded complexity.

It is important not to try articulating the link to it's extremes. The closer a link is to its extremes shortens its effective length and causes the undesired steering feature. I used the longer links which allow more travel before they do this. I also made it a point to set the ride height so that the link was nearly parallel to the ground and when the suspension was fully compressed the link was nowhere near its available travel. (I'm not sure if this is very clear?) We approached the design from different directions. I designed my axles, suspension, and frame first and am currently working on the drive train. I like the mLA connected to the pneumatic cylinder to function as the "orbital" valve for the hydraulic steering. Can't wait to see how that turns out for you.