Wheel replacement.
 

I'm doing some research into swapping out our hi-grip wheels with other wheels in a KoP chassis. After some research, I have a few lingering questions.

1) Is it really worth it to switch away from the higrip wheels? Is there a large amount of benefit to going to some other wheel, especially if you're being defended against? There also doesn't seem to be much benefit to the other durometers of the hipgrip wheel, considering the low difference in CoF and lower durabilities.

2) I've read about the performance wheels throwing tread. Is the same true for plaction wheels? I would hate to see us lose a match because a wheel threw tread.

3) If we went with plaction + blue nitrile, how often should we expect to have to replace the tread?

Re: Wheel replacement.
 

The CoF difference, even a factor of .1 or so, is pretty significant. A 10% increase in traction could win you the pushing match. It really depends on how much you can afford to spend and how willing you are to change out wheels, which isn't very easy to do on a kitbot.

Throwing tread is a possibility with any traction wheel, but properly installed tread that is riveted into place should not throw. Teams have used treaded wheels for years successfully, it's just another thing to watch out for maintenance wise.

Blue nitrile is the most durable of the different kinds of roughtop. You should expect to change them possibly once or twice a season depending on how big your wheels are, how much defense you play, etc. Other kinds of roughtop might be a once or twice an event sort of thing.

Re: Wheel replacement.
 

The blue higrips only have a .01 difference from the white ones. 1%.

That being said, the amount of time required to swap out wheels is worth thinking about. Thank you!

Re: Wheel replacement.
 

Just based on anecdotal evidence alone, I would doubt that number. The wheels handle and behave extremely differently. I know it's what it says on their website, but they really feel and behave way differently.

Re: Wheel replacement.
 

I've spoken with the engineers about this one at length (short conversations are in short supply in that office). There have been some test chassis driving around on black HiGrips, and they do have noticeably better grip that somehow isn't getting reflected in our CoF calculations--part of that comes down to the tread profile of the HiGrips, since interlocking with field carpet creates more usable grip than the same material not interlocking. I was hoping we'd have this improved by Kickoff, but other priorities had the engineers busy.

For what it's worth, Iron Kings will be running black 4" HiGrips this year and have expectations of swapping them out about once a competition day depending on our driving. The blue HiGrips are more manipulator-oriented; I don't think anyone has been bold enough to use them on an FRC-scale drive system yet because the compound is so darn soft. If you've ever rubbed a thumb on black and blue Stealth Wheels or Compliant Wheels that use the same material, you know the difference. (White HiGrips and gray Stealth Wheels are also the same durometer, just colored differently.)

Botty McBotface (the Team Indiana Ri3D build) has blue HiGrips on there, and I'm hoping to get it going against our own driver before bag day. Should be a hoot!!

(Full disclosure of the painfully obvious: I work at AndyMark.)

Re: Wheel replacement.
 

I've no idea about the actual benefits you'll see on the Field from switching away from the KOP wheels. But the perceived benefit of having better wheels may be worth its weight in gold. If having different wheels puts you just above some of the other competition in the eyes of picking teams, they'll be worth it.

Re: Wheel replacement.
 

My team has used wheels with rivet-on treads on three of our robots- 2011 (plaction wheels), 2013 (custom 6" aluminum wheels) and 2014 (andymark 4" performance wheels). We used roughtop tread all three years. We would typically replace our tread once per competition, usually before playoffs. We never threw a single tread. The important part is to keep the tread pulled tight as you rivet it down.

Re: Wheel replacement.
 

The pattern on the hi-grip wheels can, and has, peeled up the fields' gaffer's tape, causing drive-train problems. See: https://www.chiefdelphi.com/forums/s...=127368&page=6
https://www.chiefdelphi.com/forums/s...=127368&page=5
etc.

Specifically
(From Falcon Robotics)

I witnessed this occurrence more than once last year. I, personally, would use a different wheel with a smooth tread based on these observed issues and my expectation that defense will be quite heavy this year.

Re: Wheel replacement.
 

Well, I mistakenly ordered the blue higrips for our bot(wanted black) we will see how they perform on our practice bot. If wear is a big issue we my be buying more wheels.:>)