How many gears does your bike really need ? This is a subject I've spent many hours thinking about and researching gear charts on the Internet. Yes sometimes I don't have much to think about and thinking about bike parts doesn't cost me anything... for a while anyway.
The stable of bikes at our house range from single to 30 gears. I like the singles for the drive train simplicity but not so much for hills. The real debate in my head is more about crank sets, single , double, triple, I've even seen quads.
I ride a triple 52/42/30 I have no interest in a double or a compact double. The standard double doesn't go low enough for hills with a standard cassette and the compacts spend too much time cross chained.
I spend a lot of time in the 42 which has lead to me the idea of pairing a single 42 or 44 with a mountain cassette, likely a 11/34. I find I frequently double shift the rear already with my 12/26 so the bigger gaps with the mountain cassette wouldn't bother me. A look at a gear inch calculator shows that a 44 tooth chain ring with a 11-34 cassette provides the same range as my triple missing the only highest and lowest gears.
So equipment wise I'm thinking a single ring crank, new mountain rear derailleur and cassette. I'd get to delete the front shifter and derailleur. I might go to a bar end shifter for the rear as well to make matching brake levers easier. This move would be for simplicity not weight savings, my bike builds tend towards durable over feather weight.
I'm not sure when or if this will get done but will update if it comes together.
Sheldon Brown's Gear Calculator this is where I compare setup options.
