Rick's Free Auto Repair Advice

Are torque sticks accurate?

They can be accurate, but only if they’re calibrated to the wrench.

Many technicians use torque sticks to tighten lug nuts because it eliminates the need to hand torque each nut. But to be accurate, each tech must calibrate their impact wrench to each torque stick in their kit.

Here are the facts on impact torque sticks

To be accurate, they must be calibrated to you impact wrench

Most torque stick manufacturers recommend using the torque torque stickstick on the impact’s lowest or second to lowest setting. You must verify that your air or electric impact wrench is not over-torquing the lug nut. Using a high setting will still over-torque the lug nut and damage the torque stick

Even when properly calibrated, using a torque stick is NOT a substitute for final hand torquing

A torque stick is designed to apply approximately 70% of the final torque to the lug nuts while the vehicle is in the air. IT IS NOT DESIGNED TO PRODUCE FINAL TORQUE! All toque stick manufacturers state that you must apply final torque using a hand torque wrench.

Final torque must be done with some vehicle weight on the tire (enough to prevent the wheel from turning) and final torque applied by hand using a torque wrench

Torque sticks can over-torque lug nuts

The torque stick manufacturers tell you their torque sticks prevent lug nut over-tightening. Well, that’s only true if you follow the calibration instructions to the letter. Here’s how torque sticks can over-tighten lug nuts.

A torque stick is designed to apply torque to a lug nut until it reaches a set torque. If the impact wrench delivers more torque than the stick’s rated torque, it’s designed to twist until the impact wrench’s air hammer releases, at which point the torque stick will spring back to its original position.

The instructions that come with the torque stick kit advise you to set your impact on a low setting and then double check the lug nut torque with a torque wrench. However, if you use your impact wrench at a higher setting, the torque stick will still twist at the set torque, but it will also CONTINUE TO APPLY MORE TORQUE to the lug nut until the impact hammer releases. So it’s quite easy to over torque a lug nut if you don’t have your wrench properly set and calibrated.

Why use a torque stick if you still have to use a torque wrench?

Torque sticks are designed to tighten the lug nuts to approximately 70% of final torque. That way, your final torque with a torque wrench will only require a partial turn of your torque wrench instead of multiple ratchet turns once the tire is on the ground.

If you think you can do final torque with a torque stick, you’re kidding yourself.

“Torque sticks are useful, but they are no substitute for final torquing using a calibrated torque wrench. First, they should not be used to get to anywhere near final torque. Select a torque stick rated for about 2/3 of the final torque and then finish the last 1/3 of the specified torque with a torque wrench.” — The Right Torque Procedures, Tire Review Magazine

“It’s important to note that while torque sticks can be a time-saver, they are not exact by nature. Most experts recommend using a torque stick to get to about 70% of the way there, then switching to a manual method to finish. The final torque specified value is best reached by using a calibrated torque wrench.

Tightening the hardware fully with impact guns fitted with torque sticks often prevents using a click-type torque wrench to confirm the specified amount of torque is present. While a click-type torque wrench can identify when the correct torque has been reached, it cannot diagnose excessive torque.” — Tire Business Magazine

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