I’m fascinated by the testing that 1323 and 254 have brought up, and that will likely influence some of our future design choices (my team included). For the OP, I think the best answer is that Colsons are light, inexpensive, incredibly durable, grippy enough, and require zero modifications or maintenance to use, if you use the 4" versions sold by Vex. The larger Colson wheels are commercially available, but require modifications and are fairly heavy.
All of our testing was just with colsons, we actually got the advice from poofs after complaining to Tom that our auto didn’t work 
. We will most likely use these traction wheels (believe poofs used these guys too) from here on out and will most likely machine some 6" versions for 2019 to be safe.
Its quite mind blowing how much better the nitrile treaded wheels were. We went from ±2 foot spread to ±2". So for us it was a deal breaker to get a consistent auto going. We noticed zero difference in driving so it wasn’t a deal breaker for us and I believe tread was never swapped out since CVR. We’ll most likely use colsons for demo’s/random stuff and leave nitrile wheels on for competition and practice.
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Thank you to all who have contributed to the thread, this is all good info that will definitely affect our design choices next year.
We used 6 x 6" Blue Nitrile wheels this year and had 0 problems with them. In the past few days, we have been looking at the drive trains of the best teams and noting what they use; we noticed that a lot of teams used colsons, so that’s why I initially started this thread.
Drawing a conclusion from this feedback, I think if we are having troubles with finding weight to spare, we could switch to colsons, but the blue nitrile wheels seem to be the way to go.
I will note that this is basically the first game ever where precise autonomous driving was required (a) over large distances, (b) in multiple directions across the carpet, and © without vision targets to facilitate fine alignment at the end of the path. I’d caution teams to consider all of the tradeoffs before deciding to abandon Colson wheels, especially given that they track accurately enough to pull off ambitious auto modes in any other year, and whatever error they do seem to accumulate is at least repeatable.
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Super interesting!
I don’t know if you remember, R. C., that I wrote to you about our wheel tests this year. We ended up using your 6" pneumatics on the back, a 6" colson in the center, and 6" vex omnis on the front. It took about a dozen iterations to get it right.
We haven’t used rough top wheels since 2013. We put 4" dead axle Colsons on and hand-cut a zigzag tread into them for 2014. It’s cool that FRC has progressed enough that some teams are now testing not only the CoF of wheels but also the effect of the carpet grain.
Correct. It was a 1:1 swap and was quite painless. We will likely use the same wheels in the future if needed. We also really didn’t need to swap tread once it initially wore in after a few matches. If the game allows colsons, however, they are significantly less work and the preferred solution.
We had an issue this year where the drivetrain encoder counts on one side counted low by about 10%. I wonder if that has to do with colsons.
To 254/1323/other treaded wheel users: does the tread get good enough grip on the platform to climb up, or did you rely on omnis/colsons/momentum to get up?
They were the only center wheels we competed with. The omnis likely contributed to us getting up without issue, but really, we had our drivers practice driving up a lot and in the end basically told them they should only go up in one direction even though we can technically hang from either hook on our robot on either side of the bar. The consistency of them going up the ramp the same way in practice and in competition likely had more to do with us getting up reliably than anything else. Our drivers deserve most of the credit for making that look easy.
558 has been using colson wheels for years (2013-2015, 2018) to much success. We have used them like others have said due to their grip on multiple surfaces and their wear properties. I will say that on our 2017 robot that it drove noticeably better on blue nitrile due to the robots light wight and the wheels higher grip on carpet.
RC, any intention of making 3.25" and 3.5" Diameter aluminum wheels in 1.5" width?
Where do teams find 1.5" wide Blue Nitrile tread? All I’ve seen from the major FRC suppliers are 1" Blue Nitrile or 1.5" Wedgetop/Roughtop. Am I missing something?
Blue Nitrile is just a compound of rubber used to make roughtop tread/belt.
See: https://www.mcmaster.com/#rough-top-belts/=1cr2f7e
Buna N = Nitrile
The smallest width I see here is 3". Do teams cut this in half (probably do-able on a bandsaw) or is there an easier way?
AndyMark sells blue nitrile tread under the name “plaction” in a 1" width.
Bandsaw works fine. The cut is a little messy and you’ll be removing loose material afterwards, but I’ve never had functional issues.
He’s specifically looking for 1.5" wide. 1" is too small
I included that link merely to show that ‘blue nitrile’ is a subset of ‘roughtop’ and many people use the terms interchangeably.
That being said, yes, this belting is cut by teams. We use our air powered sheet metal shears or tin snips generally.
I’ve found that using a steel ruler as a guide and a box cutter works very well. Cut the material from the back (non rubber) side and make several passes, it leaves a very clean and accurate cut.
For cutting the treads we use something similar to:
https://www.amazon.com/QCM-8200M-Heavy-Desktop-Cutter/dp/B0010KTIL6
It works well and makes a clean cut but it might be a bit overkill (ours is an old stand alone one with a 5 foot handle). I wouldn’t suggest buying one for only that but if your school has one floating around it’s useful. Nice if you are splitting a 3" into 2 x 1.5" widths though
The name’s pretty neat…
Just a warning for those planning to use roughtop/wedgetop tread for the first time. There’s a whole technique for riveting the tread securely. It often requires multiple people and quite a lot of strength which can be difficult for younger students. The tread is also awesome at tearing up thumbs until they are red and sore. Cutting the tread can be dangerous if done improperly.
865’s first time using the tread at competition resulted in loosing the tread a number of times (partly because of the terrible performance wheel zip tie attachment but we even had some issues when we switched to rivets). Eventually we got the hang of it but due to the rigors of the 2014 game we were replacing the blue nitrile tread every couple matches. There was always this underlying risk of loosing a tread in a match that would of been totally eliminated if Vex Pro Colsons were available back then. My thumbs took weeks to recover.
It’s one of those things that even if there is a benefit to running roughtop over Colsons it’s very small and won’t be advantageous for 99% of teams. I have no doubts that teams with the proper setup and technique have gone entire seasons without loosing a tread but it’s just not a risk worth taking IMO.
Thanks for the info. Saw this “Tread Tool” product from Armabot.
Maybe it will help with some of the danger in cutting as provides a secure method to hold the tread for cutting length (not width) and drilling.
Has anyone had experience with this “Tread Tool”? Would this help with the sore thumbs?