Andy R":282432fu said:
I think the answer is maybe to run a short or medium cage mech. with a shorter chain - in other words , don't expect to be able to run 44/34 for example, why would you do this anyway ?
No, don't do this, really don't.
Usually it stuffs the mech through the rear spokes just for fun. The entire drivetrain jams up shredding cassette, mech and gear hanger, and also trashes the wheel. IF you a really trying hard you might also manage to wreck the back of the frame.
I know, you say you'll be careful, you'll remember. Then one day, you are riding along feeling shattered, you see something unexpected, click back and bang/crunch/splat.
If you insist on running mechs out of range, have the chain too long so it goes floppy on the small-small combo. You won't run this either but it's at least harmless. The difference is only about 3 or 4 links.
However, there is a lot of room for experimentation. The quoted capacities are quite conservative. I have run Shimano front mechs on 24T difference with no problems, and my Campag-equiped road bike happily runs a short cage with 12-23 cassette and 30/39/48 triple.