6X 775 - 6X 1.625" Drive

[Bryce2471]

Why use plate and standoff construction only to cantilever the wheels? Is the easier wheel change worth more difficult bumper mounting and greater stress in the structure?

I don't mean to poke at something that is meant to be slightly whimsical. But if there is a legitimate reasoning, I would just like to know what it is.

[Greg Woelki]

Originally Posted by Bryce2471

Is the easier wheel change worth more difficult bumper mounting and greater stress in the structure?

Yes, since the wheels have to be replaced between every match .

Nick most likely used plates instead of a piece of extrusion because it allowed him to maintain a decent amount of ground clearance. In order to do the same with a tube you'd end up tacking little plates on anyway, so you might as well simplify it.

[Richard Wallace]

Such pockets!

[Eric Scheuing]

Can we get a render of just the gearbox itself?

I'm also concerned with the gearbox mounting method. Would there be any issues with the fasteners bottoming out on each other before you can get a solid joint?

[Greg Woelki]

Originally Posted by Eric Scheuing

Can we get a render of just the gearbox itself?

I'm also concerned with the gearbox mounting method. Would there be any issues with the fasteners bottoming out on each other before you can get a solid joint?

Are you referring to the in-line standoffs? Nick appears to be using the same standoffs-and-set-screws construction method that we used on the dozens of in-line standoffs in our robot's hood this year. I can assure you that the joints are plenty strong.

[OccamzRazor]

This is very interesting but I don't think those little wheels would hold up long unless you added more of them. Ground clearance isn't the issue with this design at all, our 2013 robot was .250 off the ground and carpet was not an issue even when rolling over the pyramid corner plates.

This is awesome, hilarious, creative, well done, and a lot of other things.

I just have to wonder...

[pwnageNick]

Originally Posted by Eric Scheuing

Can we get a render of just the gearbox itself?

I'm also concerned with the gearbox mounting method. Would there be any issues with the fasteners bottoming out on each other before you can get a solid joint?

Originally Posted by Greg Woelk

Are you referring to the in-line standoffs? Nick appears to be using the same standoffs-and-set-screws construction method that we used on the dozens of in-line standoffs in our robot's hood this year. I can assure you that the joints are plenty strong.

I actually used male/female threads for the 3/4" spacing between the 775 plate and inner-drive plate. This way all the standoffs can remain installed and to take off the motors you just loosen the 4 bolts on the end of that motor plate. I'm not a huge fan of set screws in-between standoffs. I know it can be done effectively but the amount of times I've had a set screw vibrate loose between standoffs in VEX has turned me away. This would be a nice set it and forget it setup.

Originally Posted by Chris is me

Nick: Is this setup actually lighter than a traditional WCD with 3" wheels? With the thicker plate and the gears and stuff, I would be inclined to say probably not.

Short answer, no. It might save a little bit of weight but the amount you'd save is not worth all the tradeoffs you'd give up for this. I think trying to use these wheels proved to me there ends up being no benefit.

Originally Posted by OccamzRazor

This is very interesting but I don't think those little wheels would hold up long unless you added more of them. Ground clearance isn't the issue with this design at all, our 2013 robot was .250 off the ground and carpet was not an issue even when rolling over the pyramid corner plates.

This is awesome, hilarious, creative, well done, and a lot of other things.

I just have to wonder...

I debated doubling up the wheels but decided that went against the whole point of the drive, which was to save weight (in theory). Plus you could either double up the wheels to elongate their life an unknown amount, or you could just swap them out every X matches. I'm not convinced I'd go through less wheels if I double up.

Yes, I definitely asked myself if I should... multiple times. Then I remembered it's July and I had two days off work with nothing better to do, and Bailey and Rahul had already done a solid single speed 775 gearbox, so I figured why bother with something simple like that, might as well have some fun.

[ASD20]

Originally Posted by Richard Wallace

Such pockets!

And talk about all the weight savings on those wheels!

[chrisfl]

A 775pro drive gearbox could actually be viable. I know team 16 used 775pros for their drivetrain this year and it seemed to hold up really well with the unusual strain from the defenses. When talking to them at Worlds they said there weren't too many problems and it came down to the gearing. They would be better at describing it.

[JesseK]

You're only a few 10th's of an inch away from making a polyurethane roller into a wheel. Not that you'd do such a thing.

These tiny Colsons may actually see some wear over the course of 50 matches.

[Chris is me]

Originally Posted by JesseK

You're only a few 10th's of an inch away from making a polyurethane roller into a wheel. Not that you'd do such a thing.

These tiny Colsons may actually see some wear over the course of 50 matches.

Over something like 300-500 matches worth of drive time, a 4" Colson wheel will actually wear enough to negate the drop center in a 6WD. You have to be really abusing these wheels for it to happen, but it does. A 1.625" Colson would wear about 2.5 times faster than that.

Nick: Is this setup actually lighter than a traditional WCD with 3" wheels? With the thicker plate and the gears and stuff, I would be inclined to say probably not.