BEST MECANUM WHEELS

[GeeTwo]

OP: we've only used the AM 6" mecanum wheels (2014 Aerial Assist), and we were far happier with the wheels' performance than with our decision to do mecanum. They're also quite durable; our practice robot in 2014 had a CoG that was way off towards one wheel, and our practice field was asphalt (and not very recently refinished). This set of wheels survived about six weeks of driver practice, and while we would not use them on a competition robot, we keep them in our tote of prototyping wheels in case we need to take mecanum "on the road" again.

Edit: Regular (AM-0136L, -0136R, -0137), not HDs

And about the TB nano, I had the same question as Mike Marandola, so let me follow up:

Originally Posted by Sperkowsky

Sure

...

Overall we wont use them again but that was just our experience. Gear boxes in closed channel just doesn't sit right with me.

We have had nothing but success with Versaplanetaries and toughbox minis and will just use those for now on.

We have never used the TB Nano, but our air cannon is built on a nano tube structure, which is essentially two TB nano gearboxes built into opposite ends of the same piece of tubing, plus an idle drop-center axle in the middle that we link to one end by chain. We've had significantly more trouble with these gearboxes than any of our other AM gearboxes, though not quite to the extent you describe, possibly because they don't have to mount to the frame, they are the frame.

I'm also looking forward to trying out the new TB micro, which seems to have the same construction as the TB mini, but a profile much closer to the nano.

Edit: Ninja'd

[mrnoble]

We have used the basic AM 6" wheels, the HD wheels, and the vexpro wheels (all 6"). The HD are by far the best quality if you want durability and reliability over a long term. We have used them for our 2015 competition not, and for a "chairbot" which is a big hit as a promotional tool. We've probably put more than 100 hours of solid drive time on the HDs with no failures.

[snoman]

Yes cog. Is very important to make them work well . We have been using the nano tube Andy Mark drive for a few years with mecanum wheels (the less expensive AM ) and traction with omni . Just looking to see what others think. In our experience the AM we had get bent up and rollers stick they can be bent back but..

[cadandcookies]

2667 used AM 8" mecanum wheels last season and was very satisfied with them. Not sure we'll be doing mecanum wheels again this season, but they've held up quite well for the hours of driver practice and the regional, MSHSL tournament, and two offseasons we went to last year.

[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.