The width of rims can be measured in 2 different ways: the inside or the outside.
This means that one and the same rim can be indicated both in (for example) 2.15 “and 3.08″
WM2: inside 1.85″ (47 mm) outside 2.72″ (69 mm)
WM3: inside 2.15″ (55 mm) outside 3.08” (78.2 mm)
