By Bob Ciminel
June 11, 2006
Lug nuts are pretty simple devices. They're about an inch-and-a-half long with coarse threads and a head that just happens to fit a device called a lug wrench. There's probably a lug wrench in your trunk.
You put the wheel on the hub; line up the holes in the wheel with the studs on the hub, and screw on the lug nuts. Then you tighten the lug nuts until they don't move any more. Most garages use a tool called an impact wrench to tighten and remove lug nuts, and therein lies the problem.
Tuesday evening, we came out from dinner to find our right rear tire completely flat. I can change a flat tire in my sleep, so, other than being an inconvenience, I did not feel challenged. Okay, I might get a little dirty, but that's why we have soap.
My car was equipped with a full-size spare already mounted on its aluminum alloy wheel. (I drive one of those "luxury" SUVs, a five-year-old Lexus RX-300 with 83,000 miles on it and badly in need of a bath, both inside and out.) The car also had a nice scissors jack suitable for lifting 3,500 pounds of sheet metal and aluminum.
Now the most important thing to remember when changing a flat tire is to loosen the lug nuts before you raise the tire off of the ground. I don't mean floppy loose, just cracked enough that you can easily back them out after you have the tire up. Typically, that only requires putting the lug wrench on and jerking it in the counterclockwise direction until you hear the lug nut pop. That is, unless the last person who changed the tire put the lug nuts on with an impact wrench, like the folks who put the new tires on my car three years ago.
With both my son and I pulling for all we where worth, we could not budge those lug nuts. Then, I remembered that I weighed 250 pounds, and my technical training told me that, if I put those 250 pounds on the end of that two-foot long lug wrench, I ought to be able to generate about 500 foot-pounds of torque on the lug nuts. Better yet, if I jumped on the wrench, I could add kinetic energy; 250 pounds accelerating from a height of about one foot. That ought to do the trick.
It did. All the lug nuts popped loose, but one sounded a little different than the other. It was the wheel lock lug nut, a special lug nut that needs a specially adapted tool to remove it; a tool conveniently supplied by Lexus that fits on the end of the lug wrench; the tool that I used on the last lug nut; the tool that broke that lug nut.
Here's a picture of what the wheel locks looks like and the tool you use to take them on and off. They retail for about $10.00 each. They are probably made in China for two cents apiece.
We left the car in the parking lot; got a ride home; and called Firestone the next morning to tow the car to their shop and change the tire. After repairing the tire, they reinstalled the wheel with - you guessed it - an impact wrench.
He assumes informed readers will be able to tell the difference. Bob lives in Roswell, Georgia, and works for the Institute of Nuclear Power Operations. He is also a conductor on the Blue Ridge Scenic Railway.
Contact Bob at firstname.lastname@example.org