thank you for your message!
I've seen another Weinmann concave (switzerland) with a 2221 marking. Would that mean it is 559 x 21?
Also would you know why the Belgium rim I have has the marking 559 x 425 rather than 559 x 25?
weirdly, the Weinmann concave rim I have states 425 x 559 where as the similar looking one in the first post states 525 x 559. I wonder what the difference between 525 and 425 is. Maybe no difference?I don't know about the 2221 marking, but that sounds like a good guess.
But the 559 is the bead seat diameter (BSD) that's the important bit and what you need to match with a tyre, your other dimension (I think you meant to type 525 rather than 425?) I think is the actual internal diameter of the rim (added because its a concave rim maybe) presumably to aid spoke choice?
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