5" wheels
 

FIRST provided 4" wheels this year and 6" wheels last year. Where can we order 5" wheels similar to the KOP wheels?

Re: 5" wheels
 

Not quite...there are almost no 5" wheels made specifically for FIRST. There might be some 5" colsons though.

Re: 5" wheels
 

We're using 5" wheels again, however, had to make our own.

Re: 5" wheels
 

Here's some of the 5" wheels I found.
http://www.vexrobotics.com/276-1498.html
http://www.robotmarketplace.com/prod...-RENWHEEL.html

The 2nd is a manufacturer that I have never heard of, though.

Re: 5" wheels
 

The VEX wheels might not be able to withstand FRC applications....

Has anyone used them? Maybe they can provide insight about their strength.

Re: 5" wheels
 

Standard VEX VRC wheels are not rated for FRC robot weights.

Re: 5" wheels
 

The best you can do is Colsons. They are a bit heavier but they have more traction than kit wheels and will work just fine. You don't really have any other practical options that I know of. BB wheels are not suitable for drivetrains and the linked Vex wheel can't take FRC loads.

(Though you can broach those wheels to 1/2 Hex... don't ask how I know.)

Re: 5" wheels
 

The second link is for scale R/C cars. Also not for FIRST applications.

Re: 5" wheels
 

Do keep in mind that the OP never said they were to be used as drive wheels. They may be for a lower load application (intake wheels, ball handling, follower wheel, etc).

Banebots sells 4.875" wheels, though I wouldn't recommend using them as drive wheels.
http://banebots.com/c/WHB-WS-498

McMaster also carries a large variety of wheels, many of which come in a 5" diameter. To get the wheels most similar to the AndyMark KoP wheels, select a rubber tread and a "soft" durometer. Granted, these wheels are not designed specifically for FRC competition or interactions with AndyMark or VexPro parts, so some modification (namely broaching and/or drilling a bolt hole pattern) may be required.
http://www.mcmaster.com/#standard-wheels/=qdt1ol

Thanks everybody. We messed up our drive train after we cut it down to our custom configuration of 28"x27". The wheels were flat to the floor instead of having a slight tilt with the middle wheels as a pivot. This allows for better driving.

We decided we couldn't drill more holes because the difference was only 1/4". So the other solution was to put the 5" wheels in the middle to make up for it being flat.

We tried sticking the 6" wheel in the middle but the tilt was 2.5in off the ground which was way too much.

The other solution is moving the axles a little further out so it can get in the proper hole which is 1/4" higher than the middle axle. However for that we need an 825 5M 15 belt from Gates so it'll fit.

We messed up big time :(

Re: 5" wheels
 

Have you considered just switching one set of outside wheels with omni wheels?

Re: 5" wheels
 

If it the AM14U, AndyMark should have the belt you need. By using different wheel sizes, the surface speeds of the wheels won't match up and one or both sets will suffer some degree of slipping. This will lead to excessive wear and energy loss.

Re: 5" wheels
 

Raise one of the outside wheels 1/8". Drill a clearance hole in the current existing holes for your outside wheels, then rivet or bolt a new piece of metal overtop, which the axle hole raised.

I know 610 did this last year, ask them for a few pictures.

Re: 5" wheels
 

You could also attach a length of tread material (e.g. wedgetop or roughtop) to the outer rim of your center wheels. You really only need a very small bit of extra diameter in order to reduce wheel scrub while turning. Alternatively, you might try removing a bit of tread from the corner wheels to get the same effect.

The slight difference in diameters will give you some wheel scrub when driving normally, and you might see some tread wear because of it.

Re: 5" wheels
 

Try skyway wheels. (Remember them?) They used to be in the KoP and they sell a 5inch wheel.


http://www.skywaywheels.com/products_004.htm

Unlike many here...

I highly recommend banebots wheels for drivetrains.

They come in 4 7/8 diameters. They have crazy high traction. They do wear more quickly because of this though, so it is usually wise to get a spare set of you go this route. Get some blue wheels for testing, orange or blue for competition.

Re: 5" wheels
 

Ahh, the infamous Skyway wheels.
Great find!

Re: 5" wheels
 

If you do opt to go with Banebots wheels for the drive, I'd suggest going with one set of 3.875" wheels to be used on one end rather than a 4.875" to be used as the center wheel. You'll still end up with only four wheels in full contact with the carpet under normal conditions (a "pivot" as you called it), thus achieving the shortened wheelbase and improved turning. However, you'll have a much less significant difference in surface speed of the wheels (a larger diameter wheel spinning at the same rate as a smaller diameter wheel will have a faster linear velocity at the edge of the wheel). Especially if you mount the banebots wheels on the lighter end of the robot, so under nominal conditions they won't be contacting the floor (thus your four wheels with identical diamters will be in contact). You want to avoid differening surface speeds when possible, so you can harness the static friction of your treads rather than the lower dynamic friction.

Re: 5" wheels
 

Similar to this^

Drill the hold 1/8" higher. Insert "shims" under axle. The shims we have used were steel sheet metal.

Re: 5" wheels
 

If you have bolts as axles, (not live axles) you could re-drill the 3/8" holes with 1/2"(offset higher 1/8") and change wheel bearings to 1/2".

Or check a few 4" wheel brands, like the vex or Andymark traction and see if they are slightly bigger or smaller.

Thanks for the help everybody. We got it working by using aluminum plates riveted to the chassis as Gregor suggested. It works like a charm now