I have been running 8 speed components for years. I was under the impression that 9 speed cranksets had different ring gears and crank arms. I read somewhere recently that the 8 and 9 speed cranksets have the same spacing the ring gears are the only difference. So I said why don't I use a set of 2001 9 spd Shimano LX crank arms w/ my 8 speed gears. Well I compared my 8spd. Truvativ 5D's to the Shimano LX's and the spacing is off by .5mm. Are crank arms spaced differenty for 8 and 9spd?