The following commentary does not necessarily reflect the views of AgWeb or Farm Journal Media. The opinions expressed below are the author's own.
The following commentary does not necessarily reflect the views of AgWeb or Farm Journal Media. The opinions expressed below are the author's own.
As a farm machinery mechanic and writer, Dan brings a hands-on approach that only a pro can muster. Along with his In the Shop blog, Dan writes a column by the same name as well as the Shop Series for Farm Journal magazine. Always providing practical information, he is a master at tackling technical topics and making them easy for all of our readers to understand. He and his wife, Becky, live near Bouton, Iowa.
If you want to be really picky when installing wheels on cars, light trucks and SUVs:
-tighten the lug nuts to proper torque with the tire off the ground. Lug nuts are designed to center the wheel studs in the holes in the wheels. If you finger-tighten the nuts with the tire off the ground then lower the jack so there is significant weight on the wheel, the studs may be pressed slightly off-center in their holes. That increases the risk of the lug nuts or wheel hole chamfers being damaged when the nuts are torqued to proper value. And it greatly increases friction on the lug nut so the final torque value may not be accurate.
-Clean with a wire brush the threads on wheel studs. Use a bore brush to clean the edges of the holes in wheels. Do not use lubricant on the threads of the stud. Torque values for lug nuts (found in the owner's manual) can be skewed significantly by marred threads or corroded edges to holes.
-pneumatic air wrenches are bad news for wheel installation. Yes, NASCAR teams use air wrenches in pit stops, but those are $5000 custom-made tools designed to stop at precise, pre-determined torque values. Rattling on your pickup truck's lug nuts with your trusty air impact wrench risks not only stripping the threads on the lug nuts/studs, but of warping the brake rotors. If you lost the owner's manual, in general, torque for 7/16" studs is in the range of 55-65 lb./ft., 1/2" studs tighten to 75- 85 lb./ft. and 5/8" studs need 135- to 145 /b./ft. of torque.
-if you change a lot of tires, torque sticks are an alternative that allows you to accurately use an air- or battery-powered impact wrench to install lug nuts. Torque sticks look like an "extension" for 1/2" socket wrenches. The theory is that when used with an impact wrench, the torque stick spins until it reaches a specified torque, then the stick quits turning and simply recoils like a torsion spring while the impact wrench keeps rattling. A torque stick rated at 80 lb./ft. will consistently tighten nuts to 75- to 85 lb./ft. as long as the same impact wrench is used. An air-powered impact wrench running off 120 psi of shop air may give different final torque readings than a battery-powered impact wrench using the same torque stick, because the impacts from the air wrench are different than the impacts from the battery-powered wrench.
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