Highest traction wheels

[pfreivald]

Originally Posted by Boe

A custom wheel with tread of your choice i prefer mcmasters blue nitrile tread personally

Cool. Do you have a part number?

[Boe]

can't tell if your making a comment about the custom wheel part number or asking for the tread part number, but either way the tread part number 5994K852

[pfreivald]

Originally Posted by Boe

can't tell if your making a comment about the custom wheel part number or asking for the tread part number, but either way the tread part number 5994K852

Tread! Thanks!

[Boe]

no problem its worked good for us for the last two years. Last years bots tread finaly started to show significant wear after the season during demos while we were driving on pavement and concrete

[smistthegreat]

I've heard good things about cutting tread into Colsons like so: http://www.team228.org/gallery/125/b...3511-8f172.jpg

I have no concrete evidence that this increases traction, but I know 228, 125, and I think 1477 all cut their tread like this so perhaps someone from one of those teams can chime in here with some data.

In response to Pat's questions about extremely small traction wheels, the only COTS ones I can think of are Colsons and Banebots, and even the hardest (blue) Banebots wheels would have to be changed too often to be worth it. I would at least explore the possibility of cutting treads into Colsons, because the alternatives are machining intensive.

[pfreivald]

Originally Posted by smistthegreat

I've heard good things about cutting tread into Colsons like so: http://www.team228.org/gallery/125/b...3511-8f172.jpg

Cool -- that's easy to do, and the Colsons we're using are cheap enough to ruin without feeling bad about it!

[thefro526]

Originally Posted by smistthegreat

I've heard good things about cutting tread into Colsons like so: http://www.team228.org/gallery/125/b...3511-8f172.jpg

I have no concrete evidence that this increases traction, but I know 228, 125, and I think 1477 all cut their tread like this so perhaps someone from one of those teams can chime in here with some data.

In response to Pat's questions about extremely small traction wheels, the only COTS ones I can think of are Colsons and Banebots, and even the hardest (blue) Banebots wheels would have to be changed too often to be worth it. I would at least explore the possibility of cutting treads into Colsons, because the alternatives are machining intensive.

IIRC, I've heard numbers of 1.4-1.5 COF being thrown around when talking about Colsons with treads cut into them. Don't quote me on that, as I'm not 100% sure, but I will try to confirm when I get a chance.

Originally Posted by JamesCH95

Physics teachers the world over repeat this simplification. It is not true in real life. Coefficient of friction is a function of contact pressure for every traction system I've seen, namely coefficient of friction increases as contact pressure decreases.

(really awesome stuff removed to keep post length reasonable)

This is the theory I've learned and experienced with race car design/driving and some FRC teams have demonstrated through testing robot wheels.

This, all of this.

One thing that I'd like to add, is there's also a 'cleat-ing' effect (mechanical interaction) between some wheels and carpeted surface. Roughtop Tread (any form, though harder is better) and the 'W' tread on versawheels are both good examples of materials where this comes into play.

Think of something like a plastic carpet runner, the kind with little plastic spikes on one side and a textured surface on the other. If you applied traditional friction models to them, you'd see that the math just doesn't add up. (or shouldn't add up) If you dig into this a bit more, you'll start to see that the spikes dig into the carpet and make it seem like there's more friction between the two surfaces than there really is.

[George C]

We used 6" x 1.5" Colsons this year in a 6 wheel system with about 1/4" centre drop (which was too much). The drive team loves them. It's pretty difficult to tell if they're better with or without tread but after reading other threads on Colsons, we cut a diamond pattern tread in them using a dividing head on a horizontal mill. A thin slit saw set to cut about 0.100" deep slot on 15 degree intervals and about 15 degrees of parallel seemed about right. After 3 regionals and championships they show little wear. We did experience some lateral shifting of the wheel on the hubs we used but only on one or two of the outer wheels. Next year, we'll cut a coarse thread in the hub before pushing them in and maybe use a bit of PL Premium to help.

[pfreivald]

Originally Posted by George C

We used 6" x 1.5" Colsons this year in a 6 wheel system with about 1/4" centre drop (which was too much). The drive team loves them. It's pretty difficult to tell if they're better with or without tread but after reading other threads on Colsons, we cut a diamond pattern tread in them using a dividing head on a horizontal mill. A thin slit saw set to cut about 0.100" deep slot on 15 degree intervals and about 15 degrees of parallel seemed about right. After 3 regionals and championships they show little wear. We did experience some lateral shifting of the wheel on the hubs we used but only on one or two of the outer wheels. Next year, we'll cut a coarse thread in the hub before pushing them in and maybe use a bit of PL Premium to help.

Nice. Our traction wheels were 2" diameter x 3/4" width Colsons with no tread pattern of any kind cut in them -- we just broached the center hole to a hex and put them on the shaft with appropriate spacers, and they worked like a charm (except for not having quite the traction we wanted.)