Help with wheel size

Hi everyone. My team wants to use two 10" wheels on the robot because we think that it will help us get over the bridge and the barrier. However, we have run into some difficulty in procuring the wheels, and it does not really seem like very many other teams use 10" wheels. Why is it that no one seems to use the 10" wheels? Does anyone have any suggestions?

The past years’ rules would normally state that you can’t use wheels of the sort, they supplied brackets for smaller wheels or your bumper height had to be quite low. People just didn’t really use them because the disadvantages outweighed the advantages. This year, they are a huge asset. I am also quite sure that the only 10" wheels readily available through sites such as Andymark are 10" Mechanums (which are not desired to go over the bump) and 10" Pneumatic wheels.

I hope that helped. :slight_smile:

You could make your own…

No, they wouldn’t. There has only been one year when wheels were specified (2009).

You could always jump up to 12" wheels, but I don’t know if you’re going to want to do that. Try Skyway wheels; they may have 10" wheels.

I was just about to suggest Skyway. We’ve used their 9" Bead-LOK wheels quite a few times in previous years…and actually again this year. Heres the link; http://www.skywaywheels.com/products_002.htm

The reasons most teams tend to use smaller wheels are:

  • smaller wheels are easier to find (at least in recent years)
  • Larger wheels are heavier wheels
  • Larger wheels also require a larger, heavier gear reduction to get them to the appropriate speed/torque

Ten inch wheels are incredibly easy to find if you have the capabilities and the desire to make them work for your application. We are using pneumatic wheels, but we knew that we wanted to have 10" so we wouldn’t have to use as much force to be able to cross the barrier. Basically we didn’t want to have the barrier be meeting the tire at a point that wasn’t below the center line of the wheel.

We found this by using everyday normal utility tires that are found all over the place. Ours are from Tractor Supply Co. and cost us a whopping $5 a piece. A little machining and some CNC plasma cutting provides the sprocket mount and we’ve got a wheel that can handle anything that we can throw at it.

So like I said earlier, if you have the desire and the ability, you can make anything work.

True, but this year there also happens to be a very specific and beneficial reason to use a larger diameter wheel.

Yes, I was just explaining the reasoning used in the past.

8" wheels are highly available on Andymark and elsewhere (including FIRST Choice). Combined with risers and with enough torque from rear wheels, it shouldn’t be too difficult to get over the barrier.

Ten inch wheels make the wheelbase shorter. The point at which the wheels actually touch the floor is well inside the robot frame which tends to allow the robot to tip as significant weight extends out over the wheels. Since the axles on larger wheels are high up inside the robot, other considerations are required to keep the COG low in order for the robot to be stable. That said, Striker, Team 101 has used bicycle wheels very effectively in the past.