Originally Posted by
chasm54
Obviously, on a derailleur set-up there is considerable overlap between the gears. A 50/17 is pretty much the same as a 34/12. So the issue is range rather than number. However, there are advantages in having a lot of sprockets on the rear cassette. With 10gears at the back one can have nice close ratios as well as a decent range. Mine goes 12-13-14-15-16-17-19-21-23-25. That means one can find the right gear much more easily than if there were big jumps between the sprockets.
Or, if you want ideally-spaced ratios, you could do as I have done for my tourer and invest in a Rohloff hub. 14 gears, equally spaced - 2nd is 13% higher than 1st, 3rd is 13% higher than second, and so on - so one has a MTBs range, from about 20 gear inches to over 100, with a perfect chain line and no duplication.
I agree that range is nice. It's the need for such close spacing that I'm beginning to question. Let's say you're not a racer. I found that it was possible to maintain a pretty comfortable pedal cadence with just 7 gears (and just one chainring, so no overlap of ratios at all), as long as I wasn't trying to squeeze out every fraction of a mph. Current gear wants you to push too hard, risking your knees? Shift down, spin as fast as you like, and go a little slower. No biggie.
I'm not considering changing anything, BTW. Just asking out of curiosity.