This chart is from Sheldon Brown's website with 5 to 7 sprocket listings. The specs are generally pretty accurate but there's always been lots of small variations in spacing, sprocket widths also freewheel/cassettes widths especially between different brands. YMMV....
Freewheel Width comparisons: Standard 6 speed FW - 34.2mm, 7 speed FW - 35.8mm, Narrow 6 speed FW - 32.4mm (Note - all 7 Speed FW were Narrow width)
Rear side of FW fits flush with the hub.
Suntour with 1mm recess
Suntour with 2mm recess.
Shimano introduced freehubs and removable cassettes in the late 1970's. They didn't catch on until the 1980's because they required a special hub which was incompatible with the existing somewhat universal freewheel standards.
They produced the "twist tooth" Uniglide freewheels and cassettes into the late 1980's. My 1988 Bianchi came with a Shimano Uniglide freewheel to go along with the Campy Victory hubs.
SIS was introduced with the DuraAce lineup in 1984. Shimano did a lot to standardize rear dropout spacing: 5 Speed - 120mm, 6 Speed - 126mm, and later 130mm for MTBs (7 Speed Narrow FWs were supposed to fit 126mm wide spacing but hub "D" widths were not always compatible).
Suntour's "Standardized" hub specs with 30mm D width for 120mm 5 Speed hubs and 36mm D width for 126mm width 6 Speed hubs. Over the years the widths were changed on many hubs by shops and owners adding washers to create more D space.
verktyg
