[Lil' Lavery]

Speaking anecdotally, W-Tread VersaWheels are the highest traction wheels I've experienced in FRC in the lateral direction. If your goal is to resist turning moments and/or being pushed sideways, you're not going to find a higher performing wheel. The points in the W-Tread will essentially act like cleats when pushed sideways. (edit: watched some old video, not quite as good in the lateral direction as I remembered, but still an overall very high traction wheel. If there's a flat floor game that facilitates 4" wheels next year, we will strongly consider W-treads)

In the transverse direction, the difference is less pronounced, and there are several wheel/tread options that will get you into the same ballpark.

In terms of drawbacks of the W-Tread VersaWheels, I'll echo Andrew that the biggest one is tread wear. Over the course of an event, you will run the points off the wheels until they begin to approximate round. In fact, when we added a high goal shooter to our 2016 robot during the post-season, we used a set of rounded-off VersaWheels we had taken off our 2013 or 2014 robot (as they were now so round they could be used as shooter wheels). This tread wear will not only impact your traction, but also noticeably affect the effective wheel radius. As the tread wears, the wheels get smaller. We actually lost a quarter-final match at MAR Championship in 2014 because our autonomous stopped slightly short of where we expected it to, causing us to fail to score. Due to this tread wear, I would at recommend at least having one spare set of W-Tread wheels ready at each event. You can either swap them out overnight or before your elimination matches (or more frequently if you can afford it). You can also get a bit more mileage out of the treads if you rotate your higher and lower wearing wheels (our 2014 sat mostly on the
"back 4" wheels, causing them to wear faster than our front wheels). I don't think you'll need quite as many wheels as Andrew suggested (especially if you re-use your elimination wheels from one event to start your next event), but the costs of replacements can add up.

For comparison, the Colson (or NPC) wheeled robots I've built have not needed wheel replacements, and blue nitrile roughtop treads on traction wheels have lasted nearly two events before significant wear appeared (granted that robot was a good 15-20 lbs under the weight limit).


Additionally, because of the very high lateral traction, you'll want to be conscious of your wheel placement, wheel drop, and loading. Turning scrub can be a serious concern for any high-traction drive, but the higher your lateral traction, the bigger the issue can be if you don't plan for it. Excessive scrub can lead to significant current draws during turns, potentially risking brown outs (or even breaker trips in 6 CIM drivetrains). It's an issue that can easily be worked around, but you have to be conscious of it.