You broke WHAT??!!
 

One of our lead students, who's name will not be mentioned, though his initials are Jon, dropped a wheel on the concrete floor. OOOoooopps!!

Re: You broke WHAT??!!
 

I am...impressed.

Re: You broke WHAT??!!
 

is it cracked all the way through, or just through the white plastic?

Re: You broke WHAT??!!
 

normal wear and tear?

Re: You broke WHAT??!!
 

oh man, that's pretty bad. hopefully you have and extra.

Re: You broke WHAT??!!
 

I'm concerned that these wheels break this easily.... How high was this dropped from?

(what I'm getting at is that if FIRST is requiring me to use a system that can't handle a competition, I won't be the happiest...)

Re: You broke WHAT??!!
 

If a robot almost tips over, then doesn't quite tip and slams back down on its wheels, I suspect this will happen.

Re: You broke WHAT??!!
 

I don't think the impact force from hitting FRP on top of carpet is anywhere close to that of concrete.

Re: You broke WHAT??!!
 

I doubt the competition field will do anything like this to a wheel. The FRP on top of carpet ends up being fairly compliant.

Re: You broke WHAT??!!
 

I think someone posted a picture a few weeks ago of an almost identical break. It seems like if you drop these wheels from a over a foot or two you run the risk of breaking them. I doubt we'd see anything like this on the competition field because I'd imagine it was softer than concrete or some other hard floor. IIRC there's carpet under the FRP?

Re: You broke WHAT??!!
 

Keep in mind that these wheels will support up to ~40 lbs each, multiplied by the rotation radius of the tipping bot. Perhaps that's not as bad as a single wheel on concrete, but I think it's a valid concern.

Re: You broke WHAT??!!
 

Yikes! I'm surprised it broke that easily...

Re: You broke WHAT??!!
 

for stuff like this i wish i could see it from a high speed camera. then you'd realize its not that hard to crack one of these really hard wheels. if anyone is interested in a good show watch time warp on discovery. it takes random things and tapes them on high speed. i think its cool

Re: You broke WHAT??!!
 

i just look at that say to myself, really. they seem you know umm tougher

Then that (i wonder if FIRST will make you pay for replacement wheels if one gets destroyed in competition or if you will be charged a foul for not having rover wheel in contact with the ground...
I can easily see some impacts having more then 40 lbs for pressure on one wheel this is why i state the above, or through quote unquote normal wear and tear they become damaged enough that they could break in the event of a high speed... high force collision

Re: You broke WHAT??!!
 

I have seen a bowling ball crack when dropped on concrete. I'm not to worried about these wheels. Yet.

Re: You broke WHAT??!!
 

Maybe you should be. I know I was since day 2 or 3.

Re: You broke WHAT??!!
 

This happened to us around week 2ish. I'm not sure if we plan on replacing it yet, I'm about to post on Q&A to see what they say.

Re: You broke WHAT??!!
 

Just the white plastic.

Yep, we just swapped it out with one of the wheels we had put on the trailer we made. Now the trailer goes thump, thump, thump.

The drop was between 3.5 and 4 feet. It was loaded with two sprockets, two spacers and an AM 500 hub.

Re: You broke WHAT??!!
 

It probably won't happen much during competition. How do I know? We've done that a few times already(in one day too!:o). Nothing wrong with the wheels for now, and that was onto a hard surface. As mentioned before, it will be even less likely to happen with the carpet underneath the regolith.

Re: You broke WHAT??!!
 

who ever did that must have to tap and debur everything for a week:D

Re: You broke WHAT??!!
 

Team 980 had a KOP wheel crack during week 1 after being dropped about 3 feet onto a linoleum floor. It's now a trailer wheel...

Re: You broke WHAT??!!
 

Not something you would expect. :D

Re: You broke WHAT??!!
 

I had access to a 1000fps camera, and was beginning to shoot a documentary I call "FIRST On Fire: Failure Modes at the Speed of Molasses". It featured a bunch of components releasing magic smoke.

Unfortunately, I have no time for anything these days.

Re: You broke WHAT??!!
 

I agree that the wheels are unlikely to break on the FRP or carpet on the field. Of course that doesn't mean they won't break on all the nice hard floors everywhere else the robot goes.... Guess it's more important than ever to have sturdy grips on your robot and a steady cart to move it around on.

Re: You broke WHAT??!!
 

If your concern about expensive things breaking, watch out for the control board. A driver station or sidecar (I forget which) broke because someone touched it wothout grouding themselves first (thankfully for that person we don't know who). Just be careful wen handling that stuff.

Re: You broke WHAT??!!
 

Somehow, I doubt that wheel will pass inspection ... something about a traction advantage :P

Re: You broke WHAT??!!
 

Bummer, now our secret is out. Thanks for nothing Daniel.:D JK

Re: You broke WHAT??!!
 

But how will you repair it without the handyman's secret weapon? I know! Zip ties -- the duct tape of FIRST!

Re: You broke WHAT??!!
 

Duct tape is actually legal this year, but it can't be used to enhance traction. So, this wheel has been relocated into the trailer.

Re: You broke WHAT??!!
 

Yup, right here.

The moral is, don't drop your robot!