Originally Posted by
Sammyboy
Actually, the 4 speed, whilst it gives slightly more range, and obviously closer shifts, gets a slightly lower top ratio. On a 14" wheel bike, top gear is the challenge.
Sammy,
The SA 5 speed has a wider range, 150% in top. Assuming a 15" diameter 1.5 x 16 (305) a 52t ring and a 12t cog (modified cassette cog) you would have a top gear of 97.5".
Shorter cranks would allow you to spin lower gears. I'm guessing that those Minis are best ridden seated. Short cranks are great if you want to reduce the need for standing. I almost never have to stand on my Jack Taylor, with it's 160mm TAs. Come to think of it, the Minis may have been sold with short cranks. If not, they should have been as the target market was small riders.
Except for the Mk III, spreading the rear triangle on F-Frames can be problematic.