Today's bikes are tough, but they're held together by fasteners that mustn't be stressed. Many components come with recommended torque settings. Breach these settings and you may void your warranty. It now makes sense to use torque wrenches. Torque is a measurement of torsion, a twisting force. A "torque wrench" has a spring-loaded indicator that gives a numerical readout of the amount of torque being applied through it.