Originally Posted by
Road Fan
I'm not trying to start a war, but I am confused about how far to take your statements - interpretation is my goal.
What do you mean by "standard?" Was there some sort of industry standard document that you found? Is it simply that in your career this is what you have observed, and you assume it was done that way on purpose?
I have two UO-8 and one PX-10 frame downstairs in the "Frame Room." You seem to be saying they will be shown to be out of alignment if my accurate measurement shows 120 mm. Is that your intent?
Or if perhaps it's just an "indication" of what they used to do, why is the 2 mm difference between 120 and 122 so important as to mention it and suggest that it was intentional?
There were no real industry wide bicycle standards back in the day. There was very little logic to those dimensions either! They varied from country to country and by brands too.
The French "standard" was 122mm OLN width for 5 speed freewheel rear hubs and 96mm OLN wide front hubs.
Those figures are published in
"Sutherland's Handbook For Bicycle Mechanics" and many other sources.
Most French hubs during those years used those dimensions but some rear hubs were 124mm wide instead of 122mm... Is it wrong or just French??? Who knows why?
Normandy produced millions of hubs from the end of WWII until their final demise in the mid 1980s.
Adding to the mix were hub manufacturers Atom and Maillard. Atom started making small flange aluminum alloy hubs in 1945 shortly before Normandy came to market with large flange hubs.
Maillard took over both Atom and Normandy in the 1960s. In the mid 1970s Maillard started marketing their top of the line model 700 hubs while Atom and Normandy remained low end products.
Atom and Normandy used the same internal parts from the 1960s on (except for Normandy Luxe Competition hubs which were a different design).
The 5 speed rear hubs from all 3 brands were 122mm wide OLN. Last fall I changed the axles on a set of NOS Maillard 700 hub from 122mm to 126mm on the rear and 96mm to 100mm on the front.
BTW, I like to have 4mm of axle sticking out of the lock nuts. Some people say 2mm is OK but that's not enough!
120mm wide dropouts were considered standard on most 5 speed freewheel bikes but that was just a rule of thumb.
Most bikes from the early 70s were poorly aligned. The rear triangles were rarely true.
We had to realign the stamped dropouts and fork ends on some of the Gitanes and other lower priced bikes we assembled just to get the wheels to easily fit in the dropouts and to get the bikes to track properly. Bertins were much better aligned.
We rarely measured hub and dropout widths back then. We just made them fit. We frequently had to add spacers to the drive side to get enough clearance between the freewheel and the rear stays.
Assuming dropouts on most bikes are not accurately aligned, a 2mm difference in hub width becomes insignificant.
Over the years I've seen published specs for freewheel rear hub widths of: 118mm, 119mm, 120mm, 121mm, 122mm, 123mm, 124mm, 125mm, 126mm, 127mm, 128mm, 129mm and 130mm!
verktyg
Chas.