So does Germany actually use "28" in the specification of its wheel diameter? It must be one of the few measurements in the imperial system that has survived Europe's use of the SI metric system. Are there any other cases where items are sold in imperial units (as opposed to being an integer number of inches which is translated into metric *)? If there is 1/2 inch difference in diameter of English and German 28" wheels, which one is the true diameter that you would measure? Is one the external diameter of the rim and the other the diameter of the tyre bead which is slightly smaller and has to be levered over the rin?
Incidentally, has anyone actually had to use tyre levers for fitting a bicycle tyre? I always find that I just tuck the bead in at one side, then ease it in by moving my thumbs towards the opposite side and then pull it away from the rim at the very opposite until it pops into place; and vice versa for removing. You'd think that a lever would be needed at least to make the bead pop out from the rim when removing, but I've never found one necessary. Am I unusual?
(*) For example I doubt whether 5 1/4 and 3 1/2 inch floppy and hard disks are/were advertised that way in Germany, France etc - they'd be specified in millimetres.