Surprisingly, a lot of cyclists coast down hills and don't need the big gears. I don't get it myself. I almost always pedal down hills. I like to keep spinning, and it also helps me burn more calories. I've got 53-39 chain rings on 3 of my road bikes, and I often use the 12-53 combination going down hills where I ride. Of course, if there aren't many hills where you ride, there's not much need for big gears either. My commuter bike has a 50-34 compact crank, and I often spin out going down hills, but I can live with the smaller big ring because the compact crank is great for cycling with more gear.