The lower torque value should be used when threads are not dry. 65 to 70 ft/lbs seems fine. The wheels will settle in after a while. Checking them until they are stabilized is important regardless of the torque used. And I like to just check em, whenever a hairy calibrated eyeball says one might be low in pressure, or before a road trip.

Just check 'em. Keep em tight and full of air.

Brake work, suspension components, tires & wheels, things like that when serviced, what's really supposed to happen is the customer brings their car back in to the shop after a few weeks or a few hundred miles maybe 500 miles, and everything is checked again for tightness. Nobody has time for that.

So they reef a fastener down to 120 yard/tons dry and nobody cares till it's time to remove something (hopefully) 40 years later. I get why things are done that way, under time pressure. I agree also with someone who said wheels turn truer or better tracking when torqued to spec. If it's all the same I prefer to know that it's correctly fastened and balanced etc.

 

With the 8 lug 9/16" studs (80-86) and a Ford dry spec of 140 ft-lbs its a little more important to make sure the studs are dry. If they are lubricated the stress at 140 ft-lbs is more than 120,000 psi and is 92% of yield, if yield is 130,000. Too close for comfort I make sure mine are dry and clean for assembly. Besides if you are using aftermarket studs from ebay that were "forged" in China what is the yield stress really? it's best to stay around 60 percent of yield in my opinion. Especially with all the false mill certs that have been discovered.

I agree with your approach on your old Ford...and keep checking them!

BB2

 

Here you're missing the point. Dry torque is different than lubricated. The allowance has already been made for the different clamping applied. There isn't a "better" but they are different, and needs to be allowed for.

The nuts won't loosen, the wheel won't fall off, here there won't be dragons.

I don't use non-Ford parts. The point you bring up is sort a good one, but it points even more toward the importance of using a torque wrench in the first place. "Good and tight" will likely snap something with substandard materials or processes.

I agree with your approach ... keep checking them!

That is standard preventive maintenance in every manual for every car and truck for at least the last 100 years. Probably monthly. It is a critical task whenever a wheel is removed or replaced. And that's just it, that's how these insane torques developed, overtorqued oil filters (instructions say "hand tight + 1/4 turn") oil drain plugs stripped out, and yes, wheel lugs that are torqued beyond limits by the local lube shops and service stations and DIYers.

Nobody wants to fasten them properly in the first place, probably because the customer doesn't want to be bothered with checking them even once, much less periodically.

 

A few things that have been over looked. On non lubricated unplaced bolts indicated torque and applied torque and vary as much as +/- 35% Lubricated it is +/-20%.
On tapered holes the full applied torque is not proportionally transferred to clamping load.
On stamped steel rims, the rim it's self springs so again the applied torque is not proportionally transferred to clamping load.
Yield PSI listed for any threaded faster is the minimum allowable with any quality fastener being well above the minimum rating.

Torque settings for bolts are generally 50% below yield.

There is a far greater risk of failure from under torquing than there is over torquing. (with in reason)

it is only really necessary to re torque AL rims due to plastic heat deformation most factory AL rims are relived behind the lug nut seat top provide "spring" (like steel rims) to insure retention of the clamping load.

In 50 years of messing with vehicles I have never had a wheel stud fail and only a couple back off and lose their set torque. (aftermarket AL rims). There is a far greater risk of damaging wheel studs during removal if they are stuck as torsional removal torque can easily exceed the the materials torsional yield point which is much lower than clamping yield.. This is a double whammy as this damage generally is not visible to the naked eye. Remember all bolts are designed for longitudinal clamping forces not torsional load. You will not in any case on any fastener exceed the yield strength if you lubricate the threads with an oil or anti seize and torque to specified values unless specifically noted in the torque settings. Any torque below yield is fine even if just 1% below and will not damage or weaken the fastener in a non dynamic application.

 

So cutting to the chase, what torque do you recommend for an 80-86 F250 with 9/16" diameter, 8 stud steel truck wheels? Indicate whether you recommend dry torque or lubricated and describe the proper maintenance for the studs. Same question for trucks with 5 lug 1/2" diameter studs?

 

From my engineering hand book fasteners tables.


9/16" UNF Wheel studs (Grade 8 Min) torque to 140Ft Lbs

80% of yeild is achieved at 148 ft lbs with anti seize
80% of yeild is achieved at 198 Ft lbs W/out anti seize.
So if you do them dry( which you should never do any way) a heavy 140 ft lbs

1/2" UNF Wheel studs (grade 8 Min) 100 Ft lbs

80% of yeild is achieved at 104 Ft lbs with anti seize
80% of yeild is achieved at 148 FT lbs W/out anti seize

So if you do them dry (which you should never do any way) a heavy 100 ft lbs

Now if the rim manufacture says less, then take that in consideration.


This gives a safe margin for dynamic loading and still near max clamping load.

Anti seize them regardless , get more consistent torque readings and no issues with removal.

I use and have used for decades NOALOX for wheel studs/ bolts. It does not wash off like NiKAL or Kopr-kote does eventually and prevents AL rims from seizing on the hub just put small bead around the hub and a few squiggles on the hub face no more stuck AL rims ever.

A bottle of NOALOX should be one of those standard things in the tool box. Nikal And Kopr Kote are great for higher temp applications. But lower temps NOALOX/ Alnox/ Pentrox A13, all the way. NOALOX (to 300°F) / Alnox (to 500°F) / Penetrox A13 (to 500°F) These are Electrical Aluminium joint compounds designed specifically for dissimilar to AL and AL to AL connections. They are zinc rich and the carrier is a non soluble grease substance. To be quite honest it is bitch to wash off and usually requires spirits or hand cleaner to get it off.
I use it on ALL fasteners steel stainless or what ever, and it is great for under hood elec connections also, a smear of that and they never corrode.
The unplated grade 2, 1/4" 20 bolts that were used on the under side of the old hunting trailer 35 years ago came off last summer like they were just put on.once the mud was washed off them.

 

Getting to where the rubber meets the road, you stated the dry torques ("which you should never do") as the manufacturer recommends in my owner's guides and service manuals so now if you DO use anti-seize what torques do you recommend? .

BB2

 

One other thing, what does a "heavy" 140 ft-lbs mean? You can damage a torque wrench by continuing to torque after the click.

BB2

 

Mathew you stated: "Any torque below yield is fine even if just 1% below and will not damage or weaken the fastener in a non dynamic application."

First off a lug nut on a stud of a wheel is not really a static operation. What is the load on the stud when you hit a pot hole on the highway at 100 kph (60 mph)?

If it was safe to torque studs to 99% of yield then manufacturers would down size bolts. They don't because it's not safe...in fact engineers use safety factors and tensile stress usually will never exceed 70% of yield in a static condition. They seem to target the clamping load at between 50% and 60%.

Repeated loading and unloading and dynamic loading to a fastener at or close to yield should be avoided. Fatigue from cyclical loading can strain harden a fastener and with each extension and release the stress strain curve is affected. It's called hysteresis. Not to mention that the method of determining the minimum yield for less ductile steels is based on a standard off-set because the actual yield point is difficult to see under test loads and the stress strain curve is not linear in the elastic range. Add that to the fact the material properties vary batch to batch and from bolt to bolt, compounded by cheating on the specs, and it's clear to me why safety factors are used. There's no indication at all that tension to 99 percent of yield is safe or a good idea...it's not!

BB2

 

The same values no need to change them on factory rims. It is not the stud you risk damaging but the wheels and the factory wheels have MORE than enough margin in them like a 100% margin.
Aftermarket who knows and best to ask them directly.

 

That is a myth, a very big one.
Click type torque wrenches operate using a ball bearing/lever and spring. Going past the click means you passed the ball bearings/levers over center where it flips to hit the side of the wrench.
Going past the click is no different than going to an adjusted higher torque setting.

 

This a lot of misinformation in this post and bunch of half truths.. Seems to be bits and pieces pulled form other sources.. So not sure were to even start. .


Most wheels are hub centric with the bulk of lateral sheer loading taken by the hub. And that is sheer load, NOT clamping load, sheer loading capacities do not change with clamping load unless you exceed the yeild of the fastener other wise they are fixed and static... And even in non hub centic application it is the friction between the rim and the hub that takes the sheer load NOT the fastener. The only time this force would transferred to the fastener is if insufficient torque was applied to the fastener and the bolted connection started to fret then the sheer loading would be transferred to the fastener.
For all intent purposes there is zero sheer loading on wheel studs.

There is dynamic clamping loading though when ever the vehicle corners or the rim impacts a curb . Other than curb impacts the most a fastener can see is vehicle weight (1g cornering) multiplied by the lever action of the rim diameter to stud hole Wheel diam meter will factor but it is elastic so as side forces increase the lever action percentage decreases.
And this is spread among multiple fasteners. You would be hard pressed to load single fastener with vehicle weight even in a curb impact as the rim/tire will absorb a large portion of this, suspension components will fail before the wheel studs will,

And Engineers ( As I am one) DO NOT usually never exceed 70% of yield of fasteners in a static condition or keep the clamping load at between 50% and 60%. The safety margin is whatever is called for in the design parameters there is NO hard and fast rule rule here. Generally you do not want to exceed 90% in static or dynamic applications with loading factors included as above this point is where fatiguing may start to be an issue to due to inconsistency's in fastener quality. and it gives that bit of a cushion. And remember posted sheer, yield, and tensile strengths are the MINIMUM requirements to meet that particular specification, don't buy cheap knock off fasteners and this will never be an issue.... This also why many critical fastened connections call for a specific fastener from specific manufacturer. As there is NOT 50% safety margin there may be only a 5% ,margin.

And Fatigue fracturing failures ONLY occur when stresses exceed the fatigue strength (yeild) of the local material. You can run 99% of yield forever with NO ISSUES, exceed it once and you start the processes of fatigue fracturing. Loading and unloading a fastener does not initiate fatigue, but exceeding yield (fatigue) does as it has been exposed to forces above fatigue it loses elasticity in the grain and brittle's (Elastic hysteresis ). Fatigue in fasteners starts with ratcheting in the threads when yield has been exceeded, the ratcheting will grow as the fastener is cycled and presents a path for fatigue beaching to propagate across the fastener till eventual failure.






.

 

According to the mfr. of my torque wrenches they say not to use it on hard or stuck fasteners and to store it at the lowest setting. Doing these two things will mean that your torque wrench never needs calibration. At what point does over torquing beyond the setting start to mimic a stuck fastener? If you want a higher torque set it for that value. What is a heavy 140? 145? Then why not set it for 145?

Using 145 ft-lbs on a lubricated 9/16" stud will exert 125,000 psi of stress. I don't think that is appropriate. I agree with Tedster that if you use lubricant a lower torque value is advised. What that value should be is up for interpretation. For me I will continue to use the spec of 140 on clean and non-lubricated 9/16" studs and then apply a thin film of corrosion protection on the threads afterwards and be confident that I have the proper clamping loads on my studs.

With lubricating there are so many variables. Type of lube, applications of light to heavy and what about on the face of the nut at the rim contact? IMHO if you want to use lubricant to set your lugs then use a lower value of torque than the dry spec. I'm not going to advise anyone on that value. You're on your own!

BB2

 

An no torque wrenches need calibration on occasion as the spring inside wears in, storing it unloaded insures the spring does not take a set throwing the settings further off at the ends of the scale.
The reason they say not use it for undoing stuck fasteners is so you do not damage the ratchet assembly or bend the handle as it possible and in some cases quite easy to exceed the structural torque capabilities of the torque wrenches due to it's their length. And it best to store it so the internal spring is FULLY unloaded regardless what the lowest torque setting is this insures that the internal spring never takes a set at a specific torque again throwing the scale off.


The figures I quoted were for unplated fasteners W/ and W/out anti-seize were taken directly from my ASME (You know they guys that set mechanical engineering standards and specifications) engineering handbook for fasteners. Think I'll trust their settings that are based on scientific testing and real world application testing and experience as opposed to what you THINK is appropriate....

The coefficient of friction does not change much between the types of anti seize and the figures listed are the with the lowest coefficient of friction you would experience with anti-seize. And ALL anti sizes state apply to the threads ONLY, if you gobber it on like drunken sailor and you end up over torquing a fastener then the only person you can blame is yourself for shoddy workmanship...

SO it comes down to believing what the professionals say who set the standards for the fundamental engineering principles in the modern word or what you think is appropriate.
Ya I know what basket I'm putting my eggs in to...
This may also explain why I have never wheel stud fail or back off on factory wheels in basically half a century, their is a far greater risk of stud failure slightly under torquing than there is of slightly over torquing. there is no chance of fretting with wheel slightly over torqued but their is if they are under torqued.

And FYI Ford torque values have ranged from 115 Ft lbs to 260 Ft LBS on 9/16" 18TPI wheel studs.

 

I'm not saying 140 dry, Ford engineers are setting the spec. I'm just following their spec. I don't have the qualifications to doubt them. Perhaps you do. Until Ford issues a service bulletin on lug torque I'm following the current spec.

BB2