1. Snake

    Snake Mopar Nut

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    Never done this on my American Rims but If I was to use a tourque wrench how much should one tourque them.Just wondering.
     
  2. abodyjoe

    abodyjoe Well-Known Member

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    I do mine to 90 ft pounds
     
  3. irelandmoss

    irelandmoss Well-Known Member

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    Somebody put American wheels on my son's car and torqued them down so bad
    I broke 3 tools. After getting them loose I e-mailed them to find out. They say to
    torque them at 100 lbs. Just my 2 cents worth.
     
  4. RustyRatRod

    RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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    Don't forget that aluminum expands and contracts at different rates than the lug nuts and washers that hold them on. That means that over time, they will work loose. They need to be checked about every oil change or so and retorqued as needed.
     
  5. moparornocar72

    moparornocar72 Jack Of All Trades

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    Torque them at 90 ft lbs. Drive around for a few days then re-check the torque, especially if these are brand new wheels!
     
  6. dgc333

    dgc333 Well-Known Member

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    The torque is dependent on the size of the lug. The numbers below are the typical guide line numbers to use for dry threads, lubed threads will be less.

    7/16 in. 70 - 80
    1/2 in. 75 - 85
    9/16 in. 135 - 145

    The torque value doesn't change because of the wheel material and a properly torqued lug nut combination will not loosen because of a normal temperature changes. When torqued properly the force clamping the wheel on is much greater than the force generated by different expansion rates of different materials so nothing moves and nothing loosens up, if it did then aluminum head iron block engines would always requiring re-torquing.

    Not torquing your lug nuts can result in warping of the drum or rotor. This is because the uneven clamping of the wheel to the hub/axle will cause uneven stresses in the drum/rotor that manifests it self as warpage when they get hot then cool down. This phenomena is such a concern in aluminum headed engines that even a torque wrench is not accurate enough to provide even clamong and torque to yield bolts are used thus elminating the inaccuracies of a torque wrench.
     
  7. RustyRatRod

    RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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    Checking lug nut torque is a part of every single manufacturer's recommended maintaince schedule I've ever seen in every service department I've ever worked in. Turning wrenches since 1974, that's a lot. That includes GM, Ford, Chrysler, Benz, Volvo, Toyota and a lot of independents I've worked for through the years. Those recommendations come from engineers with technical minds far greater than mine and I've never questioned them and never had a wheel run off in over thirty years. There are even TSB's out on retorquing lug nuts at different intervals on some makes and models. As hot as wheels get, they need to be retorqued just as part of your regular maintainance routine. Failure to do so can be catostrophic. Just because you've not experienced it, doesn't mean it's not true. Go to any wheel web site and you'll see even they recommend retorquing on a regular basis. Even Larry Shepard talks about it in the Mopar Suspension manual. .....and I sure ain't arguin with him. ...and by the way, aluminum heads have special torque to yield head bolts designed to let them move around just enough so as not experience just what you describe.
     
  8. dgc333

    dgc333 Well-Known Member

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    Gee, in my 30 years of working on cars I have never seen a requirement to re-torque wheel lug nuts in an owners manual, had the FSM for my 03 PT Cruiser handy and checked just to make sure I wasn't missing something, no recommendation there either.

    FWIW, I am one of those engineers, I developed the torquing requirements for the assembly of the engines used in the F14 & F15 jets as my first assignment out of college so I know a thing or two about torquing fasteners.

    I stand by my statement that a properly torqued lug nut will not loosen up under normal temperature changes. I should have explained a properly torqued though. Putting on the nut and tightening it with a torque wrench does not mean properly. The threads must be free of rust, crap, nicks, burrs or any other anomaly that can create friction in the threads. The contact face between the nut and wheel must be in the same condition. Anything less and you can use the most accurate torque wrench made and the clamping force in the joint will be all over the place. Because of the difficulty consistently having the same amount of friction, using a torque wrench to create a consistent clamping force is only slightly better than doing it by hand. That is why torque to yield bolts are used and why race engines are assembled using indicators that measure bolt stretch instead of torque.

    A little threaded fastener 101: In order for a threaded joint to stay tight the force generated by tightening the fastener must generate more clamping force than the forces generated due to use, temperature changes, vibration, etc that are trying to force it apart. As long as the clamping force is never exceeded then the joint will stay tight and no motion between the two pieces will occur.

    The joint between a cylinder head and block absolutely can not have any motion or the head gasket will fail in short order. With the advent of aluminum heads and iron blocks the need for consistent clamping force across the surface of the head and block to prevent any motion became much more important than it was with iron on iron.

    If you look at a torque to yield bolt there will be a section between the end of the threads and the head of the bolt that is smaller in diameter than the root diameter of the threads. This guarantees that as the bolt is tightened stretch will occur in this area. Because its much easier to control this diameter and the metallurgy of the bolt the force the clamping force generated for a given amount of stretch can easily be calculated to a high degree of accuracy. This also provides the information necessary to calculate the clamping force once the bolt is stretched beyond its elastic limit (yielded). So, now you have a number of bolts all generating the same clamping force within a percent or so verse using a torque wrench that can have as much as 20-40% variation in the clamping force for the same torque level.

    Not to try and discredit Larry Shepard but he is talking about racing situations where stock parts are being stressed to the ragged edge or beyond. It's very conceivable that clamping forces are being exceed motion is occurring allowing fasteners to loosen. By redesigning the joint with larger fasteners with higher torques for more clamping force the need to retorque is not needed. No uncommon to see drag cars with 9/16 or 5/8 or large studs using correspondingly higher torques.
     
  9. koryliss

    koryliss Well-Known Member

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    I do not disagree with any of the comments in the thread ... but heads up.. "the book" says only ~55 pounds....

    WheelCropped (Small).jpg
     
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