Originally Posted by
PDXaero
An "ultra" freewheel is narrowly spaced freewheel made by a few companies in the 80s. For example an ultra 6 is the width of a standard 5 speed freewheel and an ultra 7 is the width of a standard 6 speed freewheel.
Also to the OP
Be sure to have cogs and freewheels in their own category as they are not interchangeable.
If you want to replace your freewheel with a individual cogs you will need a new hub or a rebuildable freewheel.
I understand now. I am looking to replace a freewhell, not a hub with a cassette.
I just want to know if I can swap out a six speed Regina Extra freewheel for a Dura Ace 7400 seven speed freewheel. I have been looking at NOS regina six speed freewheels on Ebay but they are all the same corn cob ratio I have now. What I want to do is find a freewheel I can use that is maybe 13-26 instead of the 13-20 I have now. All the Regina/Sachs ones I see for sale are the same close gear ratio. The wider range freewheels all seem to be Shimano uniglide and I'm still not sure if that will work with my Campy SR derailleur and a Regina chain.