I beg to differ with Hillriders, otherwise usually spot on, advise. The bolts are not what keeps the pulleys from freely rotating. The pulleys have a bushing bearing (most often) which has a sleeve running through the pulley. On either side of this sleeve, and the pulley body, are two dust covers. The sleeve is slightly wider then the pulley body so with even very high bolt torque the sleeve just is trapped within each dust cover and the pulley is free to rotate on this sleeve. The Shimano SIS upper pulley has a slight bit more of this end play. So the bolts only need to be tight enough to not come loose and no more. Andy.