3.25" Colson Wheels

Where do teams source 3.25" colson wheels for use in drivetrains. Is there a supplier that sells them or do you take 3.5" wheels and turn them down to the proper size?

Not colsons, but Vex sellsVersaWheels in 3.25" diameter. Also available are 3.25" omni wheels.

We bought them and shaved them down on the lathe.

-Brando

+1

Just curious, what’s special about 3.25" Colsons? Why not use them at 3.5" or 3", both of which are available without modification from VexPro?

3.25" Colsons make it convenient to switch some wheels to omnis without a change in ratio. I heard that quite a few teams turned colsons down this year due to ridiculous wear on versawheels in a drivetrain.

3.25” wheels would allow a team to run a mixture of Colson and Omni Wheels (VexPro) and/or easily Swap them to VersaWheel DT’s. Shaving .25” or so off of a colson wheel is easy on a lathe, and there’s also the bonus of removing the “crown” normally found on Colsons.

We’re swapping our 3.25" Versawheels out because of the expedited wear that we saw with them. We probably put about 10-15 hours on the drive before we noticed the considerable wear. Once we get an in-house lathe, this will likely be our route as well.

Heads up to everyone regarding 3.25" colsons. The nature of a smaller wheel means accelerated wear on the wheel. Additionally, a smaller wheel radius means any change in the diameter has a great effect on the %age of wheel circumference lost.

Ultimately, we should have swapped out our 3.25" colsons every competition. Since we didn’t, we had to adjust auto modes since the robot would drive progressively less per revolution of the drive wheel as the competition went on. Not a fun experience!

We’ll likely go back to 4" wheels for a flat-surface field.

-Mike

Thanks for the insight Mike. I can chime in that our autos we’re ending up short a Beach Blitz because of this very fact. A few quick wheel measurements and we were back at it. I’m thinking for MTTD we check every few matches just to make sure we’re still getting the results we want.

I’m curious to see if we have the room for expanding the wheel diameter to 4" from 3.25".

Is there any reasonable difference between Colsons and Versa DT Wheels?
They are about the same weight and the same Coefficient of Friction.

I have heard that the Versawheels wear out significantly faster.

Frankly, the published CoF on wheels doesn’t really tell you anything. Diamond tread VersaWheels are good, quite grippy. But they wear out just over the course of a competition and the performance changes more drastically as they wear than Colsons.

Regardless of Colson size (at least for sizes up to 4 inches), you’ll get more consistent performance if you rotate them throughout your drive over time. If you don’t rotate them, you can wear away your drop-center, changing the performance of your drive, in addition to the previously stated issues with autonomous driving distance.

If you never, ever want to touch your drivetrain again after you build it, I would either use 4 inch or larger Colsons, or use follower-wheels for your autonomous mode to track actual driving distance. Ideally, a follower wheel won’t wear out in the same way as a Colson.

What does each of you see as the main causes of the wheels wearing down so quick? Accelerating too fast and spinning the wheels? Turning scrub? . . .