6 Wheeled Tank Drive Help

I want to go with a 6 wheeled tank drive where the outer wheels are 4" omnis and the inner/middle wheels are non-omni because it allows some easy turning as well as it’s harder to be pushed off of the platform. I have a problem with this though because although they’re called 4" onmi wheels, they aren’t actually 4" (more like 4.125" ish), meaning I can’t use 4" tractions by themselves. Does anyone have any solutions? I’ve heard of using antislip or rubber bands to increase the size of the wheels, but I’ve never done it myself so I don’t know if that’s viable. Does anyone have any examples of teams doing this since I tried looking but couldn’t find any? Thanks in advance.

I once saw somebody put screws in the roller of an Omni wheel so the rollers wouldn’t be able to rotate

Mount the wheels to the frame using pillow blocks on the bottom of the structure so that you can add some spacers to lower the traction wheel.

If you’re going to power all six wheels, you may also want to adjust for the difference in diameters if you adjust the height of the axle instead of adjusting the diameter of the wheels.

@callen that’s exactly why I want to increase the diameter of the wheels, but I don’t know how to. I’ve never seen it done and work before. Do you have any examples of teams doing this?

Ya, I don’t blame you on that one. You might try taking off the tire, inserting rubber bands or similar on the wheel, and then replacing the tire. I’m not sure how much it will stretch. From a post above it sounds like you want to pick up 1/8 inch in diameter, which may be doable. I’m suggesting putting something on the wheel instead of over the tire if the tire will stretch enough because you’re less likely to run into trouble with the tire catching on something than with what you would have put over it catching on something.

I don’t know if this has been established, but are you using the stock or high traction tires?

I vaguely remember reading on a forum post that the outer traction rim removed and put on a large gear comes out the same as an omni wheel, although I don’t recall the sizes.

@TeamTX I’m pretty sure it’s the 30 toothed high strength sprocket (~3.9" diameter) with the 4" High Traction Tire. The sprocket has a bigger diameter than the plastic piece of the 4" wheel, plus the thickness of the 4" High Traction Tire should make it to about 4.125". Also, the 4" High Traction Tire is made of a material that is elastic enough to be stretched over the sprocket. I’m pretty sure with this setup, you don’t need to fill it in with any material.