Thread: New Vex Mecanum
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Unread 24-03-2015, 02:44
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FRC #3132 (The Thunder Down Under)
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Re: New Vex Mecanum

To add on a slightly different data-point:

We've been using the VEXpro 8in mecanum wheels which I believe have the same tabs as the OLD 6in and 4in.

The wheels have been holding up nicely, one set been through a regional and a few hours of practice, the other set seeing ~20 hours of usage. We're seeing wear in the roller bearing (bushing?) such that the rollers can now wiggle side-to-side. We're concerned that this may be the beginning of the failure mode that was seen on the OLD 6in and 4in wheels, can anyone who used the older wheels confirm or describe the failure?

We suspect that the wiggly bearings are allowing the rollers to rub against the tabs and lock up, but we don't have enough data/knowledge about mecanum to put any weight behind this claim.

One other thing, how do other teams fasten to these wheels? We're using #8-32 bolts into the tapped holes, but because of fear of shearing the plastic, these loosened over time and came out. We've added longer bolts, tightened them up more, and haven't seen any more of these failures yet, but we were wondering what is the recommended/common practice for attaching to these wheels. (We also saw similar failure in the bearing retention bolts, but these have just been removed).

I expect most of this post will be irrelevant once VEX have moved all of their 8in stock from last year, but more data is good right?
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Tim W
FIRST® Team 3132 - The Thunder Down Under
Sydney, Australia
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