Originally Posted by
fritz1255
OK, I think I get it. On a 10-speed, as I reach the top of a hill, I am obviously on the smaller front sprocket, and keep shifting to the smaller rear sprockets as the hill gets less steep. When I am going down the hill and can't keep up even on the smallest rear sprocket, I simply switch to the larger front, and there is not a drastic change in gearing. Certainly makes more sense than having to go from smallest front/smallest rear to largest front/largest rear to go to the next gear ratio. Conversely, at the bottom of the hill going up, I have to change from largest front/largest rear to smallest front/largest rear, rathe tahn having to switch totally over both front and rear. Somewhat counterintuitive to an engineer such as myself, but mnakes perfect sense when you see it in terms of what you actually do when riding. However, I still thing that most of this could be done with a 5-speed, either with rear derailleur or Sturmey-Archer type rear hub. Would be much simpler to operate for the vast majority of riders.
With today's technology you could easily use something like a single 42t chainring in front and 9 or 10-spd cassette in back with 11-32 range and have similar range and spacing to the old "10-speeds" without the need for a front shift at all but why limit yourself?
If you want to get creative, SRAM makes an internally geared 3-spd cassette hub that they normally spec with a 9-spd cassette and a single front chainring effectively giving you a "triple" with 27-speeds. You could then mount a double chain ring crank on the front and come up with all sorts of creative combinations. Sheldon Brown has done something like this on a few bikes i believe