pic: 4wd Geared WCD

[Cyberphil]

Thank you very much guys!

You are probably familiar with another no-chain-gang, 25. They use a similar approach to you and use larger wheels.

As for cutting weight, what thickness is the wall on that tubing? Going from 1/8" to 1/16" wall cuts the weight in half. You could also probably be more aggressive on your lightening of the gears. Steel is quite dense after all. (This applies to inside your shifters too) And don't forget, sometimes having a lot of weight down low is a good thing.

I would consider 25 our sister team, and yes, they are the ones that inspired our team to create a gear-driven DT in 2007. And 12 lbs of the weight is from the 1/4 in gears. I did not go crazy with lightening holes because it was just an exercise I was working on. I am sure I could get the weight of the gears down to about 8lbs or so, but like I said, it is more of a exercise.

This setup makes it somewhat difficult to attach bumpers outside of the wheels, particularly with 8" wheels and bumpers that have a very specific 'zone' of placement. The Poofs get away with this by mounting their chain on the inside of the wheel rails, allowing them to mount metal brackets to reach the outside for bumpers -- is it possible to do the same with the gears?

I understand that this design would make it hard to mount bumpers outside of the wheels if the bumpers were down low again like 2007-2009. And yes, I very well could mount the gears inside of the frame. Thats a great idea actually!

I'm also not sure that the setup would weigh 56 lbs; if it's an issue you may want to double check it, or investigate using other materials for gears (or thinner gears).

Another note, it weighs that much with the Supershifters and the motors also. I could cut a lot more weight on the gears if I spent the time on it.

One of the big ways to save weight, and what 25 does, is to take advantage of the massive idler gears to provide a massive speed reduction. If you put a tiny pinion on your CIM output and use the same giant gears for your wheels, that's a large reduction you no longer need to do inside your gearbox.

Very good point. The only reason that I set it up this way is because our team is very happy with the speed of our robot with a direct output shaft to the wheel. Our robot goes 16 fps in high and about 10 fps in low I believe, and this is with 8in wheels, and a direct output to one of the wheels.

We like speed.