The lug nuts and lugs on your wheels are what hold the tires to your vehicle. A few 3-inch bolts are the only thing between the wheel and the vehicle. Too much pressure on these bolts will sheer the bolts, leaving your wheel bouncing down the road as you drive. Tire torque is determined by the manufacturer and is vehicle specific. However, general rules of torque apply to all vehicles.
The amount of torque applied is measured in foot pounds of torque. Manufacturers set the level based upon the materials used in the construction of the rotors and lugs. You should always consult a dealer or tire retailer for the specific torque for your vehicle. You can use general specifications based upon your vehicle type. Heavy-duty trucks should use approximately 120 lbs. of torque. Standard trucks and full-size sedans should use 100 lbs. of torque. Compact cars and most foreign vehicles use 80 lbs., while subcompacts use between 45 and 60 lbs. of torque.
You should hand-tighten the lug nuts upon reinstalling the tires onto the vehicle. Before applying further pressure, always wiggle the tire to ensure it is fully seated. Use your standard lug wrench to turn the lug nuts an additional rotation once you are sure they are fully seated. The torque wrench is used when the vehicle is on the ground. Slowly apply pressure to the torque wrench until it clicks. Rapidly pressing down on the wrench will force the nut to be torqued higher than recommended.
A torque wrench is a ratchet with an internal clutch mechanism that clicks when the desired torque is reached. Other variations have a display to show how much torque is applied, but those are less accurate. The clutch or click type is calibrated by the manufacturer and should not need recalibration unless it is damaged. You can use extensions on the torque wrench to make the 1/2 or 3/8-inch head reach further into the wheel well without impacting the torque. Adding an extension to the handle, however, will increase the amount of torque applied.
