(2025-09-22, 5:57)tom alphin Wrote: Does anyone happen to have any insight into the original question - whether both "30mm" and "30.4mm" wheels are actually the same diameter or not?
I think one reason might come from how we choose to describe these.
All ldraw description should be the same. Rim (width) x (diameter) in millimeter. The rim and the tyre share a common size, here it is "30".
They belong together.
If I check all of these in ldu they all measure 76 ldu, which translate to 30.4 mm
And then we round it of to the nearest integer. No decimals, 30mm