My loaded touring bike uses half step plus super granny gearing. 7
speed cassette. Either 14-16-18-21-24-28-32 or 12-14-16-18-21-24-28.
Chainrings of 45-42-20. 1991 Deore DX 110/74mm bcd crankset with the
separate washers for the inner chainring so a Avid Microadapter 2
allows the use of a 20 tooth inner ring. Front derailleur is a
Shimano Sora 8 speed double. Bar end shifters.
With a 3 tooth spread in the front rings (45-42 or 42-39), a 12-32 8
speed or a 9 speed with 11-34 or 12-34 will work quite well as half
step cassettes.
James Thomson said:For reasons I won't bore you with, I'd like to try a half-step and granny
gearing system. I'm willing to entertain suggestions that it's ill-advised,
but I'd like to try it for myself all the same, and I have most of the parts
I need to get started.Likely gearing will be 45-42-granny at the front, and either
11-12-14-16-18-21-24-28 or 12-14-16-18-21-24-28-32 (eight of nine) at the
rear.Questions:
What front derailleur would you choose, and why?
Given the above, what size granny would you shoot for?
Shifters will be either older Campag Ergos, Shimano barcons, or downtube
levers, so front indexing isn't an issue.Thanks,
James Thomson