Which mecanum wheels to buy?

[buchanan]

Originally Posted by Ether

How does fewer rollers cause the wheel to act in a slightly less round way?

There isn't any reason they must necessarily, but it does seem in practice that the 8" AMs do act that way. Some possibilities:

• The curvature of the rollers may simply be incorrect for the wheel geometry. Has anyone confirmed that it's exact?
• There may be significant bending deflection of the rollers across their width, changing the effective wheel radius depending on where on the rollers the load is.
• Since the radius, and hence the thickness of the rubber, is different in the middle vs the end of the rollers, the compression of the rubber itself under the same load will be different at different points. This can be compensated for, but only at one load value, right?

I have not investigated any of them to see which is/are of practical importance, but I can confirm the observed phenomenon, and it surely does have an explanation somewhere in theory.