To get the range of that 9x28, you'll need an 11x34. The 34 will need a derailleur with a longer cage. The longer cage will hang down further.
But I'm still not following you. Somebody has a Capreo-pattern rear hub on their folder. Shimano discontinued the cassettes. Now there's a convenient source for replacement/spares. Are you suggesting they rebuild a rear wheel with a new hub, buy a different derailleur, fit a huge front chainring...to save money on the cassette? No, seriously, I've missed your point. Could you re-explain?
The points, plural, which should be obvious from reading my original post are as follows:
- Capreo harks back to a time when wide-range cogsets and RD capable of spanning them were relatively few or altogether non-existent. Conditions today have changed, with the easy availability and low cost of 11-36T cogsets (and upwards) and RD like the Shimano Zee and the Microshift Shorty. It is now possible, indeed relatively easy to get greater range from a cogset than one would get from a Capreo 9-28T without worries about low-hanging, vulnerable RD. They have become non-issues.
- For reasons of efficiency, wear/durability and proprietary parts, Capreo was never a great idea. It was a necessary expediency back in the day. It's even a worse idea today.
As one who routinely rides a 16" (ISO305) folder, has ridden one for years, and has toured on one in both First-World andThird-World conditions and terrains, including literal cross-country hauls, I am fairly confident in saying that I know about low-hanging RD and range. As one who literally builds his own bikes, I am intimately aware of what it takes to build, re-build and specc a bike. Now,
if you are already invested in Capreo already, by all means, go ahead and buy those cogsets as replacements. But if you are not invested in it, there are several good reasons (I've outlined them now
twice) to stay away. And if you are chasing top-end speed with a folder, with an inefficient double-suspension (ISO355 or ISO406) folder, with an inefficient 9T cog, your judgement is suspect, no matter how expensive, hallowed and revered your bike is, no matter how much coin you dropped on it.