Exactly where are wheels measured? Is the width measured at the outside of the rim or inside? I'm guessing the outside, but maybe it varies with the manufacturer?

And the diameter? Measured as with a giant outside caliper in the bead channel?

Thanks

Width is measured to where the tire bead contacts the rim - inside the flange. Diameter is also measured where the bead seats. You can get close enough with a tape measure.

More:
http://www.rsracing.com/tech-wheel.html#backspace

_________________
"When you find a big kettle of crazy, it's best not to stir it." - Pointy-haired Boss

1964 Valiant V200, 225/Pushbutton 904
BBD, CAI, HEI, LBP, AC, AM/FM/USB, EIEIO

Thanks. I needed that!