I've run into this argument before, this model has 8.5 mm plastic wheels (all the catalogs list them as 9 mm and later made Cresta's may indeed have 9 mm wheels). The 9 mm wheels don't match (too big) and I will have to find another 8.5. Many seem to think there are no 8.5 mm plastic wheels but it is a real size. The third wheel I found came off a 74a refreshment canteen (one of the canteen's wheels was broken, one was good) and they are 8.5's (as well other models having 8.5's). Some worn 9 mm wheels will measure close to the 8.5, but are still not the same.
