BEST MECANUM WHEELS

[electroken]

230 used the 6" VEX mecanums for Ultimate Ascent and again for Recycle Rush.

For the most part, they worked well for us in Recycle Rush, particularly in the later parts of a match when space between stacks got tight and maneuverability became more important. We did experience some sensitivity to irregularities in the flooring under the carpet during the autonomous period, even with gyro stabilization and encoders on all 4 wheels. As a result, our 3-tote auto was less consistent than we would have liked (but cool to watch when it worked).

In Ultimate Ascent they allowed for easy alignment to the feeder station and for fine aim adjustment down field, but we got pushed around too easily.

The first batch we bought suffered from fatigue failures of the blades supporting the rollers after about 100 matches. The sets we used for our 2 Recycle Rush machines held up MUCH better.

[Tom Line]

We used the previous iteration of vex mecanum and had breakage problems - these were directly addressed by Vex design changes last year. The failure mode was always the same - they fractured at the junction between the tab that supports the roller and the hub of the wheel. It made us a little gun shy so we went with the AM HD mecanum and had stellar results.

I stick by the idea that a single failure is too many - everyone in FRC knows what one loss can do to you in a competition. As a result we'll stick with the AM HD until Vex has a longer track record without failures.

[Chris is me]

2791 used the 6" Vex mecanums last year and they worked flawlessly all season. Even after getting a tether tangled up in them, or tipping and falling onto them, they didn't break. The true roundness of the wheel really helps make driving smooth.

With a really good gyro and some code, you can really make these work smoothly. I would recommend follower wheels if you are attempting accurate autonomous path planning.

Now, when is mecanum a good idea? I wouldn't do it in most cases; 2015 was an exception as it made landfill stacking significantly faster and the field had many tight corners. Plus obviously the lack of defense.