HiGrip wheel

[RandomStyuff]

Hi,
Teams in Israel have to wait until tomorrow to get their Kit of Parts, so I was interesting in hearing from teams that have, how are the HiGrip Wheels included in the KoP? Are they a legitimate alternative to traction wheels?

[Jeffy]

First look (no testing), says yes (for traction purposes).
They have ~1/8" deep rectangles embossed into them that take half the width of the wheel and alternate.
However, we don't plan on using them because we doubt the strength of the spokes.

Edit: according to Andymark, they don't have a better CoF than roughtop or wedgetop tread.

[the man]

They look sweet. The good old drag across the carpet test showed they were quite grippy. But we most likely wont use them because they are only 6in diameter wheels making getting over a 4 in bump quite iffy. But I like them very much and hope they will make other sizes soon.

[Ninja_Bait]

One of our mentors thought they looked like LEGO wheels.

I agree with Jacob; maybe we'll wait for next year.

[penguinfrk]

The HiGrip wheels seem nice. They're lighter than the 6" plaction wheels on AM by 38% (.5lb each as opposed to .81lb).

A google search for TPU Rubber wheels went nowhere. Is there any indication that it will be offered in larger sizes? Smaller sizes?

[Bruceb]

The size of the wheel does not necessarily keep you from going over the bump. Just build a slippery ramp in your chassis in front of your wheel so you slide up and over. That being said, we are using 8 inch wheels.
Bruce

[Billfred]

We played with them a bit. I'm not certain that they'll see use on 2815's robot this year (in COTS or modified form), but they do look like an upgrade over prior designs with the divider as it is.

Teams I've been on have used variations on modern kit wheels for several years with no issue on the spokes. If we chose another wheel, it wouldn't be on that.

[PhantomPhyxer]

Our Team was in two Regionals one at Medera, CA, Central Valley Regional and the last in San Jose, Ca, Silicon Valley Regional. Our 6' HiGrip KOP Wheel worked great in the first regional. While we at the second Regional the Janksters, Team 1976 reported that they had a wheel failure and ask us to borrow a wheel. However, we did not have a spare wheel. We took a look at our wheels and fould a broken spoke on a rear wheel. Upon further investigation we noticed the wheel was split across the tread. We did not have enough time to change this wheel until the next match. Thank you 2144 for giving us a wheel. The Janksters broke two wheels at SVR. I will not use these wheels next year.

[EricH]

Originally Posted by PhantomPhyxer

However, we did not have a spare wheel. We took a look at our wheels and fould a broken spoke on a rear wheel. Upon further investigation we noticed the wheel was split across the tread. We did not have enough time to change this wheel until the next match. Thank you 2144 for giving us a wheel. The Janksters broke two wheels at SVR. I will not use these wheels next year.

Have you contacted AndyMark? Inform them of the problem (pictures should help), and hold off on declarations of not using the wheels next year until AM has had a chance to look into why they are failing. You're not the only team with these failures, as you know. AndyMark likes feedback, and likes to fix problems with their products promptly.

And two competitions on a single set--back when I was a student on a team, we could go through two sets of AM and McMaster wheels in an event, minimum one set. We'd usually take some time on practice day to change out from the previous event, wear through the wheels by the end of elims if not before, go to the next event, repeat. (We'd also buy quite a few spares.) You guys put a ton of drive time on those wheels, so I'm not terribly surprised that they would have broken eventually--fatigue plus impact will take down quite a few things, let alone a wheel.

[PhantomPhyxer]

Thanks for the quick response. Like I said two teams at SVR had problems with these wheels. Our team 2643 and 1976. Team 1976 was paired with 254 and 118 to win SVR. But they broke two wheels. Yes, I am waiting to hear from Andy Mark. These wheels seem to be pretty grippy. But I think the drive train can over power the cross section.

[Zyrano]

Originally Posted by PhantomPhyxer

Thanks for the quick response. Like I said two teams at SVR had problems with these wheels. Our team 2643 and 1976. Team 1976 was paired with 254 and 118 to win SVR. But they broke two wheels. Yes, I am waiting to hear from Andy Mark. These wheels seem to be pretty grippy. But I think the drive train can over power the cross section.

It was 1967 that had suffered the wheel failures, the wheels survived CVR without a problem, the students then added an extra pair of cims (4 total with the kit bot transmission), and added a little more defensive components that moved the CG up slightly. This caused a more hoppy robot, which also got into a few serious pushing matches. We actually broke 3 wheels throughout the event, one being last year's high grip that another team had loaned us. I don't think the wheels were bad, just didn't survive the abuse we were putting it through...

Here is an example...

http://youtu.be/048HHG8m6A0

Thanks to the 3-4 teams that loaned us wheels (the team didn't think the wheels would break and didn't pack any extras), including 692, 3933, 3482?, and others!

[Wren Hensgen]

An interesting side note. Team 225 had a KOP 6-wheel chassis, with 4 inch wheels to help keep our center of balance lower. However, we discovered at our first competition that the sharp edges of the wheels mean they bite into the carpet when pushed sideways, which contributed to our tipping in a couple matches. Roughtop wheels move sideways more easily, which helped us stay up.

5545, a rookie at our first event also had an issue with them. They were a defensive robot that got slammed around a lot, and they managed to shatter the center of the wheel so that the bearing had nothing to sit in, and they flopped around the axles.

[Pault]

I am very surprised to see so many complaints with the HiGrip wheels. Team 3958 really loved using them this year. We had them in a 4wd with a wide (32x24) robot. Turning was very easy because of our short wheel base, and our robot was really good at pushing and resisting getting pushed. The first half of this video is a good example.

We can't really speak for durability. We had absolutely no driver practice during the build season, and we missed half of our matches during our first of two competitions. We also did not make it into eliminations for our first competition. And because we were a floor pickup robot, we were not subject to lots of crossing the field at full speed. So we were not putting the wear on our wheels that most teams were.