1993 Yo Eddy size - what happened here?


New member
I finally got my 1993 Yo Eddy frame last monday. Bought as a size M (serial on ebay was 183Y3M), but when I looked under the BB, the serial is 183Y3ML.
Now what I don't understand: I have a 1991 Monster Fat which is definately size M. I took some measures from both of the frames and figured out that they are absolutely identic except the steerer tube which is 98 mm for the Monster and 106 mm for the Yo. Why is the Yo a size ML when the seat tube lenght and the top tube length are identic to the size M Monster? Could it be some custom made or what is it?