pic: VEX Mecanum Concept Wheel

[Jeremiah Johnson]

Originally Posted by Lil' Lavery

He is referring to the "lock bars" that make the wheel spin with the axle, not the spacers.
Kit ($8):

http://www.vexlabs.com/vex-robotics-...it-parts.shtml

Oh... heh, thanks. But Vexlabs has all metal lockbars that work 10x better and are sold in 8 or 4 packs...

[JesseK]

You could use the metal lock bars, however you'd run into a problem when lining things up with the axle since most supports are not 90 degrees to the axle. I need the plastic ones since they are adjustable.

Edit: You don't run into this problem with FRC mecanums because the axles are round whereas VEX are square.

[rachal]

Are those white nylon spacers your rollers? Just wondering, why are they so tiny?

About the curvature of the rollers, my team (FRC) built a set of custom mecanums last summer and we were originally going to CNC lathe the rollers, but we realized that rubber labstops were almost the same shape, squishy enough to conform to the floor, and much cheaper. They might not behave as well at the VEX scale though, I wouldn't know.

[JesseK]

Rachal --

Keeping the VEX mecanum wheels into the realm of "competition legal" is pretty tough when it comes to designing the rollers. The link that lavery posted way back up in the thread seems pretty solid for traction, but I have fairly limited tools at my house and can't cut into the metal like that with any accuracy.

Alot of the "heat shrink" that's floating around and "molding" that's floating around concerning VEX tells me people are trying to craft their rollers themselves out of non-VEX materials, which isn't competition legal.

When I get home, I'll update the pic with pricing, including what part #'s you have to purchase from vexlabs and then a price breakdown including what spare parts are leftover.