Dear Tom and Ray:

I had my tires rotated in Las Vegas. One week and 926 miles later, the right rear wheel fell off while I was in Northern California. The Dodge dealership where my Ram 1500 was taken told me that the most likely cause was that the mechanics in Vegas did not adequately tighten the lug nuts when they rotated the tires. But the shop that rotated the tires won’t accept responsibility. They claim that if it was something they had done or failed to do, the wheel would have come off immediately and I never could have gone for a week — and definitely not for 926 miles. Is one week and 926 miles a reasonable time and distance to travel before the wheel would come off if the lug nuts had not been adequately tightened? Who do you think is to blame?

RAY: The shop that rotated the tires almost certainly is at fault here, Phillip.

TOM: If they had forgotten to put the lug nuts back on entirely, then, yes, the wheel would have fallen off much sooner. But if they just didn’t tighten the lug nuts enough, the vehicle could go 900 miles before a wheel fell off.

RAY: I’ll tell you exactly how it happened. How do I know? Because I’ve done it! All shops use a pneumatic wrench to tighten lug nuts. And they all have torque adjustments on them. So you can dial up or dial down the amount of torque (twisting power) on the wrench, depending on what kind of job you’re doing.

TOM: If someone turns the torque all the way down, it would be obvious to the mechanic that something was wrong, because the wheel nuts wouldn’t tighten at all. But if the torque was turned down just part of the way, for instance, to tighten a chassis bolt, the guy putting on the lug nuts might not notice that. And if he didn’t think to check the torque setting, your lug nuts wouldn’t go on tightly enough.

RAY: Then the wheel starts to wobble very slightly, and that wobbling loosens the nuts a little more, which makes the wobble a little more serious, which further loosens the nuts. And after several hundred miles, bada bing — your wheel falls off.

TOM: I’d say there’s a 99 percent certainty that this is what happened. And if I were you, I’d get a letter of opinion from the California dealership, and take it, along with this column, and give the guys at the Vegas shop one more chance to pay for the damage and any expenses you incurred because of it. Remind them that they’re lucky nobody was injured. Also remind them that they have insurance for exactly this sort of mistake (all legitimate shops have what we like to call bonehead insurance).

RAY: And if they refuse to pay up, sue them. Get a few more corroborating opinions from honest mechanics, take this to small-claims court, and you’d win hands down. Good luck, Phillip. Don’t let them get away with stonewalling you.

www.cartalk.com