Torque sticks, also known as torque-limiting sockets, are color-coded extension bars used when mounting wheels. When you tighten lug nuts with a high-powered impact wrench, it is easy to over-torque them. This can stretch the wheel studs, damage the alloy wheels, and warp the brake rotors. A torque stick acts as a torsion bar that absorbs the impact force once it reaches a preset torque level, preventing the socket from spinning any tighter.
Each stick is rated for a specific torque value, like 80, 90, or 100 foot-pounds. As the impact wrench hits the torque rating, the stick begins to twist slightly with each strike, absorbing the excess energy. While torque sticks are fast and convenient for busy tire shops, they are not a substitute for a final check with a manual torque wrench. They should only be used to quickly snug the nuts close to their target values.