As we are on the verge of the 2014 FRC season, I have a question for everyone. I been looking at the versawheel from vexpro and been wondering, what would yall recommend. We have been using Traction wheels since 2011, and the bad thing about them is when the wheel thread wears out you have to go and replace the thread or the wheel if you have spares with you. Now I was wondering how did the versawheel handle the abuse of multiple regionals and State/World Championships and off season events. Did the wheels last or did any of them fail.
what would everyone recommend?
If I remember correctly, someone posted a picture of the versas after a couple of regionals. All that was left of the versa treads were nubs.
With that being said, my team used traction this year, and we were as happy as could be. If you’re finding that the tread is wearing too fast, perhaps considering using the nitrile material from McMaster.
-Traction wheel has a lot more traction and experiences less wear and tear over time
-When you buy traction wheels, or if you have to change traction wheel tread ever for any reason (wear, tear, damage, etc.) I find it difficult and obnoxious to cut (it is dense stuff!) (especially to the right length, even with math) and to drill rivet holes correctly (without the rivet tearing the matrial)
-Versa-wheel have only slightly less traction, and wear out after only a few hours. (of on-the-field time) after 2 regionals, they have significantly less traction.
-Versa-wheels are very cheap. For only a couple bucks apiece, replacing them once or twice in a season is affordable.
-Versa-wheels perform better as exterior wheels in a tank drive (in my opinion) because they are more tolerant to lateral forces than traction wheels
-Versa-wheels can’t realistically break. traction wheels can lose tread, snap into pieces, or do all kinds of not-so-funny things to your drivetrain if they break.
-Versa-wheels are more suited to high speed robots rather than high traction bot’s. The Versa-wheel comes all in one piece, is balanced radially, and looks slick.
Traction wheels are probably the popular opinion, as they have proven themselves.
Versa-wheels have several cons, but also a lot of pros too they also work great if you are demo-ing in high grass with probably-too-muddy-to-demo-a-robot soil)
We used only versa wheels this year (6w tank) and I had mixed opinions of them.
We went to 2 regionals this year, and we had a few good shoving matches against traction and Coleson wheels. Our wheels did well at our first regional, but traction did start to fall off by elims of the 2nd.
I think a combo of both wheels might be a good idea: a 8 wheel drive with 4 traction wheels in the center and 4 versa wheels on the outsides.
Versa wheels have significantly greater forward traction than lateral. I don’t have conclusive test numbers, but they seemed to have slightly more forward traction than traction wheels last season. However, unlike traction wheels which have roughly equal lateral traction, versa wheels slide sideways quite readily.
I would say Versa-wheels may have more traction fresh-out-of-the-box, but they certainly loose that advantage quickly.
This is why I suggest using drive train with a mix of both wheels. You may be able to get away with a non-drop center configuration because the versa-wheels can slide so easily
We used Versa Wheels last year for our 6wd. We ended up going through three sets of them through four events (2 regionals, Championships, and IRI). We didn’t have any problems with having to buy multiple sets since they are so cheap. I personally don’t have a lot of experience with traction wheels, since we only built one practice bot that used them, but I never felt like our robot was at a disadvantage to robots with traction wheels because of the Versa Wheels. I would recommend at least buying a set to put on a practice robot, since they are so cheap. IMO they are a really cheap alternative that is almost as good.
Yeah I agree. I am still not sure which I prefer.
With a fresh set of wheels, and a robot completely maxed out (120lb bot + 20 lb bumpers + 13lb Battery) with the standard VexPro Ball shifter (2 stage, default gearing) geared down again 1.4:1, we still ran out of traction before running out of torque in both High and Low gears.
Personally, I think the Versa Wheel is the best ‘bang for buck’ wheel out there, with it’s only real issue being tread wear. Subjectively, I’d say that they wear about as fast as gum rubber rough-top tread, but have superior traction characteristics in the fore/aft direction, while having a lower lateral COF (makes turning easier.) If you’re looking for a long term wheel solution (something that doesn’t wear) then blue nitrile is probably your best bet, or a colson wheel.
The trick to using Versawheels is to design the drive around them being removed at least once per event, and if your budget is friendly enough, have a complete second set of wheels (with hardware) on hand to swap for a worn set. This is what we did, and a wheel swap (6 to 8 wheels each swap) could be done in about 5 minutes.
Has anyone done a head to head comparison of VersaWheels versus Colsons? Our drivetrain is set up to make wheel swaps completely painless. If we can gain traction and lose weight in exchange for having to buy a few different sets of wheels, I think that’s a worthy tradeoff. However, Colsons have proven tough to beat in terms of traction.
I’m not sure that it is true. I believe teams who have tested colsons have found that they have similar traction on carpet to 1" wide roughtop. While I don’t know how this compares to versas, wider roughtop wheels(1.5" - 2") is going to give you more traction on carpet then colsons. On the other hand, colsons have much better traction on smooth surfaces(i.e. polycarb) than other wheels.
We used VersaWheels this season and really liked them. Like other teams have said they do ware but when they are new they hard to beat. The idea that they lack lateral traction is a bit more complicated I think than people are making it out. A new set of VersaWheels that still have their corners when pushed sideways (for instance in a t-bone collision) dig into the carpets like cleats. It’s pretty hard to move them.
It will be interesting next season when VEXpro releases the tires for their traction wheels.
I am curious how a wheel would perform if you did this to it:
Take a 1.5" or 2" traction wheel
Remove the traction belt (roughtop, wedge, whatever) or just don’t attach tread to a new one
Instead, stick that super sticky (tape side) Velcro tape onto the wheel in place of the tread, Hook side of course
Have unbeatable traction as your robot is constantly Velcroed to the carpet. (hopefully you have enough torque to unstick yourself!)
While this would be rather intresting to see, something is going to have to give when you want to turn, and im betting it would be the sticky tape, but if you want to talk about velcro there is this legend http://www.youtube.com/watch?v=2eKvva_ZCHw
Also, on topic, just some anecdotal evidence, I have seen bots using VersaWheel that were great at head to head pushing get pushed around the field when hit from the side. They may have had worn down wheels as stated in other posts, but it is still something to consider.
My vote, from what I saw with my teams bot last year is go Colson, we were pushing people left and right. Requisite GIF http://imgur.com/4eHq8lP
Just to be clear, The Beast wasn’t using velcro they were using metal file cards. Something like these. This thread has more information and for the record it is now very illegal to use metal as a traction device.
Colson does offer wider wheels up to 2" in 4" d. I like Colson wheels for traction wear and price. However it takes a bit of work to mount a sprocket on them.
The Lateral Traction of Versa Wheels probably isn’t as simple as I described it in my previous post. I also observed the ‘cleating’ effect that you’re describing, especially when being pushed from the side while not in motion or moving all that quickly. That being said, once the robot is in motion and turning, this cleating effect seems to go away almost entirely. I guess a more appropriate way to describe this would be ‘scrub’ or turning resistance.
Thinking about it more, the effective scrub could have a lot of do with the forces on the robot, in our case, our CoF was lower than most (with the arm down) meaning that while turning the robot stayed relatively flat but while being t-boned, there was a noticeable tipping towards one side (side being pushed would be lifted). I suspect that this tipping is a major player in the lateral characteristics of the wheel, if it stays flat it’s going to have more of a tendency to ‘slice’ through the carpet, but if it tips you’ll get a cleating effect.
Does anybody have CoF data for AndyMark HiGrip wheels compared to Versawheels? We’re planning to try 4" AndyMark wheels for our fall practice drive. If nobody has that data, maybe we can buy a set of each type and do some testing.
