I've always wandered whether cycling does me a load of good in terms of fell running fitness or not. I know it does my fitness some good, and also means my bad knee is bad anymore, but I always struggle on a run if I've being doing more cycling than running in any one week!
I usually ride to work and back and only have a day off the bike in the if I'm getting out climbing in the evening. So the running and riding have to go hand in hand.
As for gears - ain't it a personal thing - it should be, as people ride differently, there shouldn't be any machosim involved - I'm a twiddler on my mtb, but a cranker on my road bike. Go figure!