>>1217128On a downhill bike you don't need a bazillion of gears, five to seven usually suffice. People were using road cassettes before - pic related - but they are not fit for DH derailleurs ( road and MTB cassettes usually use different slant angle ) and road cassettes have lots of tightly spaced gears - which are also redundant on a dh bike.
So for some time now gear manufacturers offer a reduced 'DH' specific cassettes and some even offer 150/157mm hubs that can fit just those 7 speed cassettes - so they have wider bodies and thus allow for more rigid wheels.
