Warning: Do Not over torque wheel lugs!

We took delivery of a new CX-9 Sport on Monday.

I made arrangements to swap out the original Bridgestone Duelers at a local tire dealer, for (4) new Michelin Latitude Tour HP tires for $170 total/installed. The dealer took the factory Duelers in trade.

I have done this many times with new vehicles at this tire dealer, always at a great price and without a hitch.

Well there was a hitch this time. The mechanic did not use a torque stick and over torqued all the wheels. As soon as I had my 1st chance to brake at highway speeds, I had serious vibration through the vehicle.

I knew exactly what happened. The rotors were warped due to the over stress.

They tried to remount the wheel with the proper lug torque, but the damage had been done.

The tire shop is replacing all (4) rotors with OEM parts from my Mazda dealer, and my service manager confirmed Mazda would still honor the break system with proof the tire dealer used Mazda parts. Proper torque is 95 ft lbs. I figure the tire shop mechanic applied in excess of 120 ft lbs.

The service manager confirmed care must be taken with the rotors on the CX-9, particularly the front rotors.

Just a heads up.

RJ
...

i hate to tell ya but that should be common knowledge.....

the best one i've seen has been a tire shop cross threaded a lug nut on my dad's car and probably put about 150lbs on it.....i had to break the lug

if any one ever touches my tires....i usually loosen all the lugs and then put my torque wrench on 'em

I'm pretty sure most dealers don't bother hand torquing the lugs. Be careful everyone!

The service manage said 95ft lbs lug torque. The Toyo tire/wheel guide says 80 ft lbs for the 2008.

What's the proper torque?

Regarding the torque stick, they are usually (+/-) a couple of lbs, so you can get 78 on one lug and 82 on another, with a 80ft lb stick.

I agree hand torque is the way to go.

RJ
...

The manual says
79.6―108.4 ft-lb

I had an entire set of lug nuts destroyed by a shop that didn't watch their torque. A friend of mine literally had to DRILL OFF the lug nuts. It was ridiculous.

I got in the habit of loosening and retorqueing my wheels any time I had worked done on my car that would have involved removing wheels. Not only is it bad for the reasons mentioned above, but try to remove a lug nut that has been overtorqued on the side of the road with oem tools in the back of the car.

Yikes! I had no idea this was so important. I have always done it the way my father showed me -- hand tighten, drop the car and then step on the tire iron and give it a couple kicks after you hear the screech. I wonder what torque that would register.

After my first tire debacle (slid into a storm grate going about 15 MPH around a turn in snowy conditions with the hideous Duelers and burst a sidewall), I had to put the spare on the car at home. I had only hand tightened the lugs before lowering the jack and forgot to step on the tire iron after-the-fact. I drove to he deal to have a couple new tires put on only to discover that they had to order them. On the way home, I noticed a severe vibration and immediately pulled over. Then I remembered the lugs were only hand tightened and got out the iron and added some torque. I guess I was very lucky.

a month ago, I hit the dealer for basic maintenance, and they told me that I had a broken lug and that it was going to cost me about $180 to replace it. My argument with them was that I haven't taken my car to anyone but them, so if it was broken, it was something they did. The service manager argued with me, and told me that taking the lug nuts off was what did it, not on... and I called her out on it. They looked at my vehilce repair record, and finally conceded to repairing them for free.

Fortunately, I keep all of my mechanical repair receipts... and proved them wrong-- evidently, it's easy to strip or break these lugs.

be careful

P.

Never use anti-seize, or any lubricate for that matter, on wheel studs or lug nuts, or any threaded fastener, without adjusting the tightening torque. Torque values for lubricate vs dry threads would be 25 to 30% lower.

Best solution - leave wheel studs and lug nuts clean and dry and torque per manual specs at routine tire rotation intervals.

The tightening torque is created by a combination of the friction created at the lug nut and wheel contact and the friction created at the threads when the lug stud begins to stretch. The lug stud stretch creates the clamping force required for proper wheel tightening.

Any lubrication applied to the threads or lug seat on the wheel will affect the tightening of the wheels.