Vex Straight Flex Wheels -- max RPM and hub options?

Does anyone have any experimental or anecdotal idea of a max safe RPM for the 4" Straight Flex Wheels sold by Vex, similar to the expansion data published for the AndyMark 4" compliant wheels?

Also, what is the recommended way to connect the 1/2" hex VersaHubs to these wheels? The Application Example for Flex Wheel with VersaHub shows what I assume are threaded standoffs pressed into the holes in the wheels but I cannot find any detailed recommendations on this.

Looks like you can use a 1/2" versahub, with 3/8" thunderhex 217-5837. The thunderhex has a #8 hole (tap size for #10). It would just require cutting the thinderhex to length, tapping to 10-32, drilling out the versahub to clearance for 10-32, and assembly. That is the easiest way I can see to do it

Could use WCP Aluminum Threaded Hex Standoffs, they only come in 2" lengths though

Definitely use standoffs with the vex straight flex wheels as shown - if you follow the other suggestion of tapping one of the hubs you risk overtightening the wheel and could run into problems with tightening / loosening that are just a lot less likely with a rigid thing to clamp against like a standoff. Vex sells #8 threaded standoffs (you may know them from their Vex EDR lineup!)

This isn’t what you asked, I know, but since you are asking about max RPM I am guessing you may be using these in a shooter. Just a heads up though, when using flexible wheels for things like shooters you want to be aware of potential variance in shot consistency. With straight spokes like the AM / Vex wheels have, you may get different compression if the ball contacts the wheel in an area directly supported by a spoke vs the more compliant area between the spokes. I do not know if this will be an issue this year, given the large goal and inflatable game piece, but it’s something to watch out for. The more expensive Fairlane industrial rollers that teams have sometimes used as shooter wheels are less susceptible to this variance due to the teardrop profile in their spokes. If you want a little compliance in a hooded shooter, you may get good results using rubber or foam or something in the hood itself rather than the wheel.

That will probably work to use as a spacer

will work as a standoff I think

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