[Espeefan]

Hi Joe, I remember when you posted this project on Scale 4x4. I wouldn't be surprised if this thread gets moved the construction equipment section. You've got a really neat project going there and I'm looking forward to seeing it get back on the main burner. Really curious to see how you will fit everything inside the model to make it functional. I think you've got a lot of work ahead of you!

I think your best bet for the axles would be to pick up some gearhead motors, and then your hubs and wheels could bolt right to the output shaft. No other transmission would be necessary. You would only have to make an axle of some kind, or an axle tube, and mount the gearmotors inside that, or to it. If you are going for a 4wd front axle, then maybe you'd be better off with a single gearmotor and a transfer case with a center differential of some kind, which would allow for a speed difference because of the different sized tires front to rear. The more components you add, the less room you'll have inside for all the other important mechanics and electronics, so maybe it would be better to have the model be 2wd. A powered front axle would be real challenge, although in 1/12 scale, you might just be okay. There are a lot of 1/10 scale axles out there for trucks that would probably be a good fit. Tamiya's TLT-1 axle, Losi's 1/16 scale crawler axle, or in metal, RC Channel has a couple different axles with steering knuckles too. One is narrower and one is the same as the TLT-1 axle. Or head over to RC4WD's website and check out all the different axles they offer. I think you would easily find something that would be perfect. Another option, and I'm just brain storming here, would be to use the gearhead motor idea in the rear of the model, add a third gearhead motor for driving the front axle of your choice, and do the math so the ratios come out close. You might need something like a 20:1 gearhead motor on the front axle and a 40:1 set of gear motors for the rear axle, if the tires are twice the size. The front axle could always be engaged, or maybe disengaged electrically, but I'm not sure the front tires would free wheel, as it's not easy to backdrive a gearhead motor. It would better to have a shaft coupling that sides over a splined shaft to engage the front axle. I think it's kind of a horse a piece. With gearhead motors you'd have no transmission taking up valuable space inside the model, but then you'd need two or three motors. With a single motor, transmission, and transfer case, you add a lot of components. Perhaps a single gearhead motor in the center of the model, powering a transfer case, the rear axle, and a reduction box for the front axle would be in order?