Sutherland's in NUMBERS:
Regular 5 and 6 Speed
A = 29.00mm for 5 Speed
A = 35.00mm for 6 Speed <<<<
C = 120.00mm-122.00mm
Narrow 6 Speed, 7 Speed and 8 Speed
A = 31.00mm for Narrow 6 Speed <<<<
A = 36.00mm for Narrow 7 Speed
C = 125.00mm to 127.00mm
Sheldon Brown in WORDS:
In the 1970s, there was a move toward 6-speed freewheels. These were of two types:
"Standard" spaced 6 speeds had sprocket-to-sprocket spacing the same as the existing 5 speeds, around 5.5 mm
Standard spaced 6-speeds required increasing the frame spacing to 126 mm, aggravating the problems introduced with the move to 5-speed, but still providing satisfactory service in most cases.
"Ultra Six ®" spaced 6 speeds used a closer spacing, around 5 mm. This permitted an Ultra Six ® freewheel to directly replace a standard 5-speed unit on a 120 mm hub.............
They both are saying the same thing. Sheldon of course notes the problems introduced by Regular 6 and the application of Ultra-6 to older 120-122mm hubs.
As I stated back in my reply to FBinNY - there's no need for "au contraire" here.
=8-)
No typos...
=8-)
__________________
5000+ wheels built since 1984...
Disclaimer:
1. I do not claim to be an expert in bicycle mechanics despite my experience.
2. I like anyone will comment in other areas.
3. I do not own the preexisting concepts of DISH and ERD.
4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
5. My all time favorite book is:
Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life