Maybe a technodweeb question, but here goes: I typically ride my 12-speed with the chain on the smaller front sprocket, and only use the rear derailleur to change gears. I live in a hilly area where I need the lower gears, but I still thought I was a real weenie until I did some calculations: most of the gear ratios actually overlap. On "standard" 10-speed gearing (52 and 40 teeth on front sprockets, 28-24-20-17-14 on rear), all but the largest two gears on the rear sprocket combined with the 40 tooth front sprocket and the smallest two gears on the rear sprocket combined with the large front sprocket do not overlap. All others are redundant to some degree. Couldn't we achieve the same thing with a 5-speed with a 46-tooth front sprocket and a rear casette that was geared 32-26-20-16-12? Seems to me that this would work just fine for most casual riders (most of the folks who buy bikes). What am I missing here? Should I file a patent application?