[greglepore]

Actually, just for reference (Steve apparently has it under control) there are two small allen bolts that clamp the non drive arm on the the shaft after you tighten the preload bolt in the center. The preload bolt is very lightly tightened (mine are just had snug-Shimano even uses a plastic bolt at that spot)and it does indeed call for a special tool, although I've always been able to fake it with a large allen key (12 or 13mm I dunno). After this is snug you torque the nds crankarm on, 10 nm or so if you care.