Where to purchase new wheels.
 

As the build season fast approaches, we are trying to get a stock of parts to work with. This year, we're going to go with 2" x 6" wheels, and as the new captain of Team Fusion, I'm having trouble finding them. AndyMark used to have 2" x 6" wheels, but they were out of stock, and now they do not appear on their website. Also, we do not like the IFI wheels. We are looking for something lightweight as we are probably going to have a 4 motor drive train since we kept on tripping our breakers last year. So 2" x 6" wheels...

Also, on another note: looking for 22 and 52 tooth sprockets.

Re: Where to purchase new wheels.
 

custom is the way to go just see if a local company will help you out
it really is the way to go

Re: Where to purchase new wheels.
 

You might try Colson wheels. A quick search found this site, where model WC18 (6"dia x 2"W) sells for $7.50 each.

Colsons weigh a little more than AM or IFI traction wheels, and their CoF is a little less -- but the price is right and they are easy to drill, saw, machine, etc. to suit your needs.

The site above and similar sites that offer robot components will have other types of wheels, too.

Re: Where to purchase new wheels.
 

We can make custom with our new CNC machine, but we are still trying to get everything figured out, and we don't want to design them, especially since we cannot build anything until January. If we were to mill them out, that would break the rules. I think the thing that Richard posted looks pretty neat, and I'll look at that. Trust me, if we had the patience and knowhow to CNC our own aluminum wheels, we would. We ordered the shiny aluminum ones from AndyMark, but found them to be too thin for our needs. They were so pretty though...

Re: Where to purchase new wheels.
 

then make one to get all the kinks out you can design them you can not make them now and then compete we them

Re: Where to purchase new wheels.
 

GRR (973) uses pully parts for wheels. They work very well. Don't know if that helps you at all but it's something to look into.

Re: Where to purchase new wheels.
 

Well, the off-season is a good time to practice with your CNC machine. If you practice making some wheels now, I'll bet you can make it so that you can create the CNC file pretty quickly once build starts, and after that it is mostly a matter of clamping down the stock and pressing "go" a few times. The same thing goes for programming... if you figure out how to code encoders, or improve your camera tracking in the off-season, there is nothing to prevent you from using that knowledge during build... heck... that is what you are SUPPOSED to do! :)

If you want a quick alternative, however, consider wooden wheels... I've seen some very effective wheels cut out of plywood (glue a couple sheets together to get two inches) with a conveyor-belt tire. Turn a couple of aluminum inserts to hold bearings, bolt on a sprocket, use a hole saw to cut out some "speed holes" and you're off to the races.

Most importantly, however, don't forget that whatever you are planning right now could change drastically when the challenge and KOP items are announced. For all we know there is going to be a layer of washed gravel spread across the carpet this year... or we're going to have to climb steps, or cross a section of low-friction polyethylene.... or there could be 6" x 2" wheels in the KoP!

Who knows.... but you can't go wrong by learning to program your CNC machine better.

Jason

Re: Where to purchase new wheels.
 

why 6in

i'm a fan of 4in wheels if done right you can climb any ramp

Re: Where to purchase new wheels.
 

Mostly to avoid field obstacles such as ramps, bumps, and dislodged robot parts :D We're going from our 8" to 6" this year to try to get a bit more torque, and we want 2" to grasp the floor better.

I'll talk to our engineer tomorrow to see if we can make our own. I know he doesn't want to, but if we can't find decently weighted wheels, we may have to.

Re: Where to purchase new wheels.
 

Why not? The 2006 IFI wheels were not too good, but the 2007 model is completely redesigned, and they work just fine.

And 1" wide wheels grip very well.

Re: Where to purchase new wheels.
 

I agree the new IFI wheels are good. :)

Many previous threads have explored the observed principle that wheel traction depends strongly on material and texture, while it is mostly independent of contact patch area. So 2" wide wheels don't grip (much) better than 1" wide wheels if other parameters are equal.

However, double the width means half the load-per-contact-area and therefore half the wear, so wider wheels will keep their traction longer -- i.e., more matches between tread changes. And wider wheels will resist twisting more than narrow ones, so defenders will have to work harder to force you to change direction -- and your own motors may also have to work harder when you want to change direction.

Re: Where to purchase new wheels.
 

For wheels that are designed specifically with recreational robotics in mind, look at what the Robot Marketplace has to offer: http://www.robotmarketplace.com/mark...echanical.html

Re: Where to purchase new wheels.
 

I looked at Robot Marketplace yesterday, and didn't like any of their wheels. Either they were too heavy, or they weren't the right size. We're trying to reduce the weight of the wheels because we want to go with a 4 motor drive train.

Re: Where to purchase new wheels.
 

675 used a 4-motor system (each wheel, own motor) this year with 6x1in wheels. With the blue nitrile tread (motors/gearboxes were CIM's plugged in to the BaneBots 56mm 12:1 gearboxes) only one other bot could move us. And we stayed under 120lbs.

Oh, but we made our own wheels.

Re: Where to purchase new wheels.
 

If you are trying to reduce the weight, I suggest:
1. Reduce the diameter. It is possible to climb nearly any ramp with as small as 3.5" wheels if done properly. There is no reason for large wheels unless there is a step or some other such obstacle requiring them. Large wheels require large (heavy) gear reductions.
2. Reduce the width
3. Machine your own.

Re: Where to purchase new wheels.
 

When you mention that you can climb ramps with 4" wheels if you do it correctly, what do you mean?

How do you climb ramps with 4" wheels?

Thanks, Travis

Re: Where to purchase new wheels.
 

Climbing ramps depends on your frame not your wheels. So long as you don't bottom-out with the wheels you are using you can climb a ramp. (But sometimes its easier just to use bigger wheels than designing a different frame)

Here are some other wheels to consider:

Swamp Thing (179) used some really cool wheels in 2005 that roughly match your description.



The wheels came from here.

My team used 8" pneumatics from Skyway last year. They were very cheap and provided tons of traction. So much traction that we had to replace two of them with omnis :o just to turn...

They are listed as the 8"x2" wheel on the bottom of this page.

Re: Where to purchase new wheels.
 

Another place that relative width comes into play is in affecting the normal force at the wheel. While this won't impact the total normal force of the robot or it's total pushing capacity it can be used to move tractive load around on the robot. (OK, this is a theory and not a proven fact yet.) Why would this be useful? More tractive load at the center wheels of 6x6 yields easier turning by reducing the laterial skidding forces at the corners. How does this work? The carpet that supports the wheels behaves (I believe) like a spring or elastomer locally. By doubling the width of the wheel the 'spring rate' gets doubled forcing that axle to support more weight than it would otherwise. Supporting this theory is the fact that 6x6 drivetrains often lower the center wheels to improve turning.

Re: Where to purchase new wheels.
 

As has been stated it is all about placement. If you keep the wheels to the outermost extents of the robot you should have no problems climbing. We have used 4" custom wheels for 1 year now (we tested them last off-season on the jeep bot) and we have never had a problem climbing. The ramp from aim high was no problem. Ramps from last year never gave us trouble either.
We use 6 wheel drive with the center wheel lowered about 1/8" with inclined conveyor belting attached. Our wheels are 1" wide and we do wear through tread fairly well but replacement is something we need to keep up on. We are testing new materials this fall.
If you want to CNC wheels in the fall you can. You just can't use them at competition. We make a set each fall and then have a drive base the first week of the build season for programming and prototyping. We have wheels made that week and start assembling them as soon as we get them. and start putting them into the competition frame once it is established.
We looked into the Colston wheels this year to keep stuff COTS but weight & implementation kept us from going that route.
Everybody does it different but nobody does it wrong (except our 05 bot). I hope you find a solution.

Remember KISS.

Re: Where to purchase new wheels.
 

Ryan

If you’re looking for something strong and lightweight, you should really take another look at the IFI wheels. I'm not sure why your team doesn't like them, but if you are basing this opinion from the 2006 wheels, you need not worry. They were completely redesigned for 2007 from the ground up based on feedback from the 2006 season.

Over the years, 1114 has used Colson's, Custom wheels, and IFI wheels. We've found that the offer the best balance of light weight, robustness, and price of any wheels going. If next years game calls for a wheeled robot, you can be sure that these are the wheels that 1114 & 2056 will be using.

Re: Where to purchase new wheels.
 

Overseeing this year's drive train, I have the same task. Essentially, we're choosing our wheels based upon the reliability of the IFI wheels last year and the fact that the IFI wheels come with the 1.875"-diameter bolt pattern that's standard for matching up to several other KOP and non-KOP parts, such as the AM flat #25 sprockets. Since we currently are unsure about our access to machining tools this year, this is a big sell for us.