Monday, January 7, 2013

I've Changed A Lot Of Tires...

...and never worried about torquing down the lug nuts. I've used impact wrenches, tire tools, and breakover bars, and never had a problem; but times have changed. I grew up with steel wheels, and they have quite a bit of give if you overtorque the lug nuts. The nuts may be hard to remove, but no real harm is done. Cast wheels are a different animal, though. There is no give in cast wheels if you crank the nuts down too tight, and over-tightening stretches the studs, rather than bending the center of the wheel. The importance of torquing your lug nuts came home to us recently, when I had a tire repaired. One of the wheel studs spun and fell out, and this is how it looks:

The arcs across the back end of this bolt show the progression as the bolt pulled apart as we drove around in blissful ignorance.  We thought about how this could have happened, and we have figured out that the damage was caused at a tire shop in Mt. Vernon, IL.  We needed a flat fixed last summer; had to replace the tire, and had both changed on that axle.  We were back the next day, because the new tires didn't match the diameter of the tires on the other axle, and the 4WD was kicking in.  So...all four tires had been run down by an impact wrench, instead of being hand tightened the last bit.  What would you do?

We don't want the wheels to fall off of our buggy while we motor down the road, so it is in Ford Square's garage now to have all of the wheel studs changed.  We are also getting new lug nuts as long as we are doing this much.  A torque wrench will be going in the back end of the car, just in case we need tire service in a garage where the workers don't have one of their own.   If you have cast wheels on your car, buy a torque wrench, use it when you change a tire, and keep it in the jack compartment.  Watch the guy who takes your wheels off and on; insist they use a torque wrench to tighten the lug nuts.

No comments: