Since there is this difference between the FRC manual and the AM site, I just went out to our stock of discs and measured a few. Also, we looked in to the Wham-o measurement specification to see what it said.
Measured
diameter = 10.94 inches
height: 1.37 inch
WHAM-O specification
diameter = 11 inches
height: 1.4 inch
I would contend that both of these are correct. If you look at this from WHAM-O's perspective, I would guess that the specification and tolerance is very loose. They just want the disc to be able to tossed by hand and to fly. Now, we are wanting to toss them with a robot, and we want a tighter tolerance of the dimensions. After things calm down a bit here at AM, we may measure 100-200 from different boxes and different colors to see what the variation is.
Here is a link to the
Discs at AndyMark.
Sincerely,
Andy