Btw, stop by our pits in the Canadian Regional to test out your torque; 500lb load tester with digital readout.
thats made out of lexan wow… how long did it last?
Where did you find the 65 urethane? I am thinking about making something similar. Any advice would be apreciated.
anyone else know where I can find roller similar to these?
To answer the above questions:
A pair of them lasted us through the Chesapeake and Canadian regional events. They were specially designed [by students] for last year’s game to both stick very well on the HDPE and to clip onto the steel mesh of the ramp to provide extra traction 
The lexan was incredibly strong and the urethane was durable.
That urethane was provided for us by BorgWarner Automotive. Our head engineer brought sample material and we liked that version best. Then our staff of on-call machinists cut it. Have you ever cut urethane? It’s about as hard as welding aluminium so we left it up to the pros. Even then it took a week before we got it back.
We may or may not be using omniwheels this year. But if so, then expect something interesting 
Keep in mind that working with urethane isn’t a simple task That wheel gave a machinist quite a headache.
Do you think these were worth the effort?
Yes.
Er, that’s me pretending to be the machinist who cut the urethane for us. The rest was relatively simple.
when these ran did the metal touch the ground?
No, the metal didnt touch, otherwise the wheel would have been illegal.
[edit] there isnt any metal on that wheel, barring the fasteners and the shafts the rollers run on. I think you’re referring to the lexan, which doesnt touch.
Not last year it wouldnt have been. I saw a bot with entirely metal treads and they passed.
From 2003 Competition documents - rule M17:
M17 - Robot wheels, tracks and other parts intended to provide traction on the playing field (“traction devices”) may be purchased or fabricated. In no case, will traction devices that damage the carpet or other playing surfaces be permitted. Traction devices may not have surface features such as metal or hard plastic studs, cleats or other attachments. The outer surface of off-the-shelf wheels may be modified by removing tread material only. In no case may a traction device protrude beyond the bottom surface of the Ramp mesh.
If that bot passed I would say someone was not doing their job …
Metal cleats and other attachments were allowed in previous years, but this rule was added to avoid field damage which had occurred in 2002.
I believe that metal is refering to studs. a metal wheel would be permitted, assuming it wasn’t blade-ish on the edge.
The two bolts are connected to a sprocket on the otherside that is connected to a main drive chain. The sprocket was keyed for the axle.
No, actually it wouldn’t be permitted. A wheel is by definition a traction device. You cannot have any metal touching the floor, no matter what. I believe the 2004 rules are even more implicit than the 2003 rule you just quoted.
Cory
Actually, the ‘machinist’ as we will call him, had to freeze the urethane to cut it nicely. Then he froze it again to drill the holes for the axles through it. Then, he placed each and every smaller urethane ‘wheel’ on a lathe and counterbored each side by hand, which took about 2 weeks, seeing as how urethane of that type is incredibly resistant to wear and extremely…squishy.
Good game.
