Is the wheel mounting nut torque value of 100 ft/ lbs for dry threads or oiled threads?

 

dry

 

Always dry...never lube the studs or nuts...this will result in the stud being stretched which will make it prone to fail prematurely.

 

All in favor of 100lbs dry, say aye!

 

Good day...learned something.....

 

NEVER oil wheel lug nuts or studs, use a wire brush to clean them if necessary.

My neighbor oiled his lug nuts and had to get his car towed when they all loosened up and made a terrible noise. So, unless you like wheels coming off, DO NOT OIL LUG NUTS OR STUDS !

 

I use white grease, have for years.

 

I've used a small dab of anti seize on each stud on every car we've owned, especially vehicles with aluminum wheels. It helps stop the corrosion between steel and aluminum.

I've never had one loosen/fail. And I check them regularly.

 

How does this take place?

 

Ok,

When you lubricate the threads or the nuts it then becomes easier to rotate the assembly, since torque is somewhat a measure of resistance or static force. When you reduce the friction between the stud and nut it in turn causes a "wet torque" situation. There are a few situations where wet torque does apply to a fastener so it's not always dry (but for wheel nuts it is)

When you torque the wheel nut to 100ft.lbs wet...you are in fact apply drastically more force to the stud and nut than you would if the assembly had not been lubricated. This excess force can and does stretch the stud slightly, causing the metallic composition of the stud to crystallize...this weakens the stud and makes it so that the stud cannot maintain the torque applied to it.

Eventually if the stud is overtorqued enough times (read it as 3) it can snap...or crack and fail completely as you drive down the road...causing a wheel off situation.

 

The facts for the Lubed or dry question is right in your Service Manual.

 

I don't mean to be insulting, but you have no idea what you are talking about. Torquing or "pre-loading a bolt or stud causes it to stretch. The amount of bolt or stud stretch is necessary to create the necessary clamping force desired by the engineer who designed the piece.
Lubricating or cleaning the threads creats less resistance as the nut rotates along the stud and allows for more of the imparted force (torque) to be applied for bolt/stud stretch (clamping force) up to the desired end point. In the wheels studs case this value is 100 ft/lbs, not more. The amount of torque or stretch is not increased beyond the end point because the threads are clean and lubricated.

 

Here is what ARP has to say about torque and lubrication:

If the stretch method cannot be used in a particular installation, and the fasteners must be installed by torque alone, there are certain factors that should be taken into account. ARP research has verified the following “rules” pertaining to use of a torque wrench:

1. The friction factor changes from one application to the next. That is, the friction is at its highest value when the fastener is first tightened. Each additional time the fastener is torqued and loosened, this value gets smaller. Eventually the friction levels out and becomes constant for all following repetitions. Therefore, new fasteners should be tightened and loosened through several cycles before applying final torque. The number of times depends on the lubricant. For all situations where ARP lubricants are used, five cycles are required before final torquing.

2. The lubricant used is the main factor in determining friction, and therefore, the torque for a particular installation. Motor oil is a commonly used lubricant because of it’s ready availability. If less friction is desired in order to install the fasteners with less torque, special low friction lubricants are available. With special lubes, the required torque can be reduced as much as 20 to 30 percent. It is important to keep in mind that the reverse is also true. If the torque value has been specified for a particular fastener on the basis of low friction lube, installing the fastener with motor oil will result in insufficient preload; the torque has to be increased to compensate for the extra friction caused by the motor oil.

3. Surface finish is also important. For example, black oxide behaves differently than a polished fastener. It is therefore important to observe the torque recommendations supplied with each fastener.

End Quote

The important part here is the variance which can be introduced by using different lubricants, as much as 30 percent. The service manual specifies a torque value of 100 ft/lbs DRY. Using a lubricant could have the same effect as torquing the stud to 130 ft/lbs.

So, I'd say clean the threads with a wire brush and torque dry.

 

 

Yep! This is a no-brainer! ALWAYS defer to your Owner's Manual. If you don't have one, get one.

 

UMMMM wonder why ASME specs on bolt torque state clean and lubricated?

 

Link?

 

Clean and Dry. 100 ft/lbs


Tire Rack.

http://www.tirerack.com/wheels/tech/...jsp?techid=107

Wheel Lug Torquing


IMPORTANT!

Proper installation requires that the wheel lug torque be set to the recommended specification for your vehicle. Sometimes these torque specifications can be found in your vehicle's owner's manual, however more often than not you will need to refer to your vehicle's shop manual or obtain them from your vehicle dealer/service provider.

Unless specifically stated otherwise, wheel lug torque specifications are for clean and dry threads (no lubricant) that are free of dirt, grit, etc. Applying oil, grease or anti-seize lubricants to the threads will result in inaccurate torque values that over tighten the wheels.

A thread chaser or tap should be used to remove any burrs or obstructions of the threads allowing the lug hardware to be turned by hand until it meets the wheel's lug seat. Once lugs are snugged down, finish tightening them with an accurate torque wrench. Use the appropriate crisscross sequence (shown below) for the number of wheel lugs on your vehicle until all have reached their proper torque value. Be careful because if you over torque a wheel, you can strip a lug nut or hub, stretch or break a stud or bolt, and cause the wheel, brake rotor and/or brake drum to distort.



Use the dry wheel lug torque values specified in the vehicle's owner's manual, shop manual or obtained from the vehicle dealer/service provider. The chart below lists typical torque values that should only be used temporarily until the vehicle's exact torque values can be confirmed.

Since the thickness of an alloy wheel can differ from Original Equipment wheels, also verify that the lug nuts or bolts will engage the threads. Refer to the chart below to determine the number of turns or the depth of engagement typical for your stud or bolt size.


When installing new wheels you should re-torque the wheel lugs after driving the first 50 to 100 miles in case the clamping loads have changed following the initial installation. This is necessary due to the possibility of metal compression/elongation or thermal stresses affecting the wheels as they are breaking in, as well as to verify the accuracy of the original installation. When rechecking torque value, wait for the wheels to cool to ambient temperature (never torque a hot wheel). Loosen and retighten to value, in sequence. Simply repeat the same torque procedure listed above.

 

You should ALWAYS follow factory service manual specs.,that said speaking from 40 years exp. in the trade.... lube or not lube the threads,... has not compromised a wheel stud in my entire career a 1/2 inch stud being over torqued by 30 ft lbs. will not affect the integrity of the stud. whats important in threads are good and clean go to final torque in at least two steps and always observe a cris-cross pattern when tightening wheels,....used studs i clean w/wire brush and a small dab never seize,new studs dry. new aftermarket wheels,install, torque drive couple miles loosen torque again then appx. 50 mile loosen torque again I've put new wheels on torqued to specs drive 15 mile only to discover missing lugs use caution when going to large tire/brake chain stores as they usually have large air compressors with big line pressure I've seen more studs fail after wheels are taken off and put back on they usually have shop guns(ingersol rand super duty,, earthquake ect.) that are stud killers as they run into lugs that are difficult to remove sometimes when busy they just whack your lugs on and send you on your way then you get a flat and when you remove the tire 3 of 5 studs breaks. just remind them to torque the lugs if they know you are aware they will use a torque limiting socket.to be safe you should retorque yourself.last if you are very hard on brakes as evidenced by black rotors and crumbling or cracked discolored brake pads a good idea to replace studs at time of brake job.no scientific data to back up this postjust a lifetime in the auto/truck trade

 

For the most part- I agree with you.
Exception is that the majority of MAJOR tire chains have now gone to torque limiting sockets as a policy to prevent this. My store- and my local competitors now use these to avoid the situation you describe. Our store implimented this policy 6 years ago. Most competitors have followed suit. Most also use regulators on their lines to limit line pressure and further insure studs are not over-torqued.
Again- I cannot speak for all chains- but for ours- this has been policy for some time.
As far as your assesment of when to use or not use anti-sieze, you are exactly correct. I also agree with replacing studs when rotors are replaced.
Correct on the need to re-torque new wheels 50 mi after install as well.
-97C5 14 year tire store mgr