Wheel Wear

[DonRotolo]

Our experience so far is that little bits of dirt and crud do cause some minor wear of the wheels. This is made worse by the fact that they spin so easily from excessive acceleration. The marks made tend to be along the length of the tread and not the width, but by no means would I say that they wear 'a lot' - just some visible scuffing.

In our tests on the terrazzo floor (in the hallways), waxed vinyl tile floor (in the cafeteria) and a piece of "official" pebbled regolith, the regular floors are almost twice as grippy. We pulled on a 4-wheel test platform weighing about 30 pounds with locked wheels with a spring scale. We found a small (under 20%) difference between sideways pulls and longwise pulls, so those transverse CoF numbers did not pan out for us. Also, the difference between static friction and sliding friction is measurable at about 20% (sliding being less, of course).

The custodial staff was not amused by the scuffs in the school floors the wheels left. We promised to not do it again, and they forgave us.

[Andrew Y.]

Originally Posted by CraigHickman

I have a serious problem with some of the logic presented in this thread. A true FIRST student would hear that the wheels gain traction as they wear, and rather than thinking pushing the rules to the max, they'd see that this REALLY means. Folks, design your robots to allow easy swapping of wheels. If FIRST sets a max amount of wear, you don't want to have to take your entire robot apart to change out a few wheels.

in no way am i saying i will tell my students to push the rules, nor do i intend to wear the wheels down. I dont see anyone on this thread saying "im gonna wear the wheels down" Part of how i was taught was to know everything thats gonna happen and be prepared for it. I just wanted to get others feels on if i should get some extra wheels, and how it may be handeled.

[EricH]

Originally Posted by Andrew Y.

Part of how i was taught was to know everything thats gonna happen and be prepared for it. I just wanted to get others feels on if i should get some extra wheels, and how it may be handeled.

If you aren't sure your wheels will pass, get extras. If you don't need them, another team (who isn't on CD or reading the Q&A or manual) will.

[Geshamakina]

The main question is...how are they going to be able to tell wether it was through "normal" wear-and-tear??? some bots may wear out their wheels more or not at all, and we all want any added friction. How are they going to be able to tell if it was done on purpose or not??? honesty is needed here.