You broke WHAT??!!

[billbo911]

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!!

http://billbo911.smugmug.com/photos/463671797_oa5Rh-L.jpg

[Jared Russell]

I am...impressed.

[gorrilla]

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

[nahstobor]

normal wear and tear?

[meastman]

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

[CraigHickman]

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...)

[JesseK]

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

[jgannon]

If a robot almost tips over, then doesn't quite tip and slams back down on its wheels, I suspect this will happen.
I don't think the impact force from hitting FRP on top of carpet is anywhere close to that of concrete.

[Tom Line]

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

[thefro526]

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?

[JesseK]

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

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

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.

[smurfgirl]

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

[Sam2197]

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

[XXShadowXX]

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

[IndySam]

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

[NorviewsVeteran]

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

[Andy L]

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.

[billbo911]

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

Just the white plastic.

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

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.

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...)

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

[115inventorsam]

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

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.

[lenny8]

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

[David Brinza]

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...

[pheadxdll]

Not something you would expect. :D

[EricVanWyk]

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

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.

[Kevin Sevcik]

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.

[AlexD744]

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.

[Daniel_LaFleur]

http://billbo911.smugmug.com/photos/463671797_oa5Rh-L.jpg

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

[billbo911]

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

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

[Rick TYler]

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

[billbo911]

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

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.

[DonRotolo]

I think someone posted a picture a few weeks ago of an almost identical break.
Yup, right here (http://www.chiefdelphi.com/forums/showthread.php?t=72273).

The moral is, don't drop your robot!