WCD 6" pneumatic tire wear

[Bob Steele]

It should be WCP in the title and not WCD sorry

Last year we utilized the 6" WCP Diamond Tire/Wheel combination and they performed admirably in our 8 wheel drive. The only issue we had was the large amount of wear we experienced. We are wondering how everyone else did when it came to replacing these tires.

We did 3 district events, district champs and St. Louis CMP, We also did a single parade of a relatively short distance.

Below is a picture of the tires that we replaced during the season. All wore out in the middle of the tread... sometimes wearing right down to the tubes. It should be noted that 4 of these came from the practice bot.

In the 8 wheel drive we would have had a larger amount of scrub on the middle wheels so we know that some of this was from that.

Near the end of the season we wanted to switch to the other tires that WCP has (the zig zag) but we did not realize initially that they had a different wheel altogether and that those wheels were out of stock so we could not switch.

If anyone else has an experience with these please add your thoughts. Thank you!!

[Cothron Theiss]

Wow! I bet your pit crew got good at replacing those wheels. Just out of curiosity, what were the rough dimensions on the width and length of the wheel base for those middle wheels?
I can't offer any of my own experience because my team used 9" wheelbarrow tires for only one event plus practice time. They're practically brand new still. (Maybe that means we should get in some more practice time.)

[Bob Steele]

The width of the robot was approximately 24" and the wheel to wheel distance was approximately 12". The outer four wheels were 7.5" from the four inner wheels.

Outer Wheel --7.5"--Inner Wheel ---12"---Inner Wheel --7.5"--Outer Wheel

Width --outside of one tire to the other....approximately 24"

Between the regular season and our Girl's Generation off season event we have played in 102 matches.
I can't even count the hours at the practice field...

[BrendanB]

Looks similar to ours. We are currently sitting at 129 competition matches, plus practice, & demos.

We opted for the dead axle wheels using the AM 6" hub and because we were breaking so many at our initial events we were swapping wheels on a regular basis but still saw some wear on all wheels. At our second event we started swapping our outer wheels for a metal hub with some design help from Ty & 319 B.O.B. When the off-season rolled around we swapped our center wheels less frequently.

This is a picture of our tires after our last event a few weeks ago. Since then we purchased all new tires to close out our final two competitions of the year.

We initially purchased 12 tires at the beginning of the year and they all look like the ones you've posted after being rotated through the competition robot over the season.

[Andrew_L]

Wow that's some aggressive wear. We used the zig-zag tread and it's still running clean to this day (EDIT: we replaced wheels a couple of times during the season, but not too many times) - I think teams would have better results with that tread on the future. Were these just comp bot wheels, or practice bot? Were there many instances of wheel slippage in your matches, or is this just wear from normal driving and defense crossing? Did you contact WCP about the wheels when you noticed considerable wear?

[adciv]

We used pneumatic tires this year. What PSI did you inflate yours to?

[wilsonmw04]

wow, that makes our track wear look like nothing.

[Dale]

1540 had similar wear on our demo bot but I thought it was just because it was driving on asphalt. We only got one day out of them at Maker Faire Portland.

I'm now of the opinion they just aren't very robust. Colson's they aren't.

[AustinSchuh]

Originally Posted by Bob Steele

Below is a picture of the tires that we replaced during the season. All wore out in the middle of the tread... sometimes wearing right down to the tubes. It should be noted that 4 of these came from the practice bot.

This looks like your tires were over-pressurized. That'll cause the middle to take more of the load, and not spread the wear around.

That being said, I'm surprised they are this sensitive to it, but there you go.

[runneals]

We had a 6 wheeled drive and inflated ours to 20 psi and that seemed to last all season. The ones that we took off were worn, but they still had rubber on it and wasn't completely gone. We just replaced them a few weeks ago for Cowtown.
I'm gonna go with what some of the other posters said about the air pressure.

[RoboChair]

Originally Posted by runneals

We had a 6 wheeled drive and inflated ours to 20 psi and that seemed to last all season. The ones that we took off were worn, but they still had rubber on it and wasn't completely gone. We just replaced them a few weeks ago for Cowtown.
I'm gonna go with what some of the other posters said about the air pressure.

Just because the tire says "50 PSI Max" does not mean inflate to 50 PSI.

You can put 30 inch off road tires on a 4 door sedan, but that doesn't mean you should...

[bowmanb]

Classic over-inflation wear pattern.

https://www.dropbox.com/s/sr9wjzc72b...-Wear.jpg?dl=0

[runneals]

Originally Posted by RoboChair

Just because the tire says "50 PSI Max" does not mean inflate to 50 PSI.

You can put 30 inch off road tires on a 4 door sedan, but that doesn't mean you should...

via the amazing experts at Good Year

Why tire air pressure is important:

• Underinflation increases treadwear on the outer edges, and generates excessive heat, which can age tires faster
• Too much air pressure causes the center tread to carry most of the car's weight, leading to faster deterioration and uneven wear

To find the proper air pressure for your tires, look in your vehicle's owner's manual, on the sticker on the driver's side doorjamb, or in the glove box.

Note the part in bold. Just because your car tires say 45-50 psi, does not mean that you should inflate them to that. My Prius says 50 psi, but my door says 35.

[Bob Steele]

The wear that we saw was not an overinflation issue in our opinion. We tested a variety of pressures and competed always on the low side.... These tires are very thin in the middle of the tread. We had pretty even wear across the tread...unfortunately the middle portion of the tread was not as thick as the outer sections. Automobile tires have nice even tread all the way across in thickness... and are quite different.

We had an 8 wheel configuration with a six CIM transmission.... there was a large amount of scrubbing going on in the two sets of inner wheels.

As an aside. Over the summer we substituted Colson solid rubber 6" wheels using the VEX hex inserts for hubs and they fitted almost perfectly and we are presently testing those vs the pneumatics on our practice robot. They work quite well...

[Max Boord]

Originally Posted by Bob Steele

The wear that we saw was not an overinflation issue in our opinion. We tested a variety of pressures and competed always on the low side.... These tires are very thin in the middle of the tread.

This was something I noticed on 179s worn tires. While I do not know exactly what pressure they where inflated to, they all showed a similar wear pattern with the tire wearing slightly more in the center but by the time we switched them out the edges where worn quite a bit as well.

Originally Posted by Bob Steele

As an aside. Over the summer we substituted Colson solid rubber 6" wheels using the VEX hex inserts for hubs and they fitted almost perfectly and we are presently testing those vs the pneumatics on our practice robot. They work quite well...

This was what 179 did on both of our robots after IRI. They seemed to work pretty good for us as well.