pic: Dented IFI Wheel

[Chris]

To expand on what Tim said,

Our experiences were very positive, like they weren't perfect but they were darn good. With what I’ve learned this year I’d use them again in a second, I’d probably change a few things about the way I used them (such as sprocket placement, and hardware used) but we were pleased.

Another important point is we fought weight hard core this year, and there is no way Irrational would've ever made weight without the IFI wheels.
We have 12 on the robot.

8 in the 8 wheel drive system
4 in the ball lift system

Chalk up one to a statisfied customer,
Chris C.
Team 229

[Richard Wallace]

The designer of these wheels visited St. Louis back in December, serving as a technical advisor for our FVC demonstration event. He left me a sample 6 inch x 1.5 inch IFI wheel.

A few minutes ago I took that sample down to the CMM that we use to check parts here at Emerson's motor tech center. The results showed that the six hole pattern intended for mounting sprockets is concentric to the bearing hole within 0.004".

Each of the sprocket mount holes was 0.197-0.198 diameter (very nearly 5 millimeters). I'd conclude that the ideal sprocket screw size would be #10, or M5 if you wanted to use metric fasteners. Off center sprocket mounting could result from using smaller fasteners such as #8.

Of course, my CMM results are from a single sample. Close inspection of the holes indicates to me that they were punched, not drilled or bored; from this I guess that the sample was made using the punch tool that IFI subsequently used to make production parts.