Torque value-HELP

[bgott]

I really didn't want to give you advice that someone would prove wrong. I torque 'em to 100 pounds-feet myself. We had a book at Firestone that gave all the torque settings on lugnuts and also all the recommended front wheel bearing tightening proceedures. I figured that chart would have it but couldn't check it ahead of time. Sorry!

 

[em14]

If the shops used torgue sticks that would help but have run into many that don't ... The problem is not only with the Fords but I have had problems with other makes ...
Leo

 

[bgott]

The problem with torqueing one down and going from there is that the first one doesn't stay at that torque. The wheel cocks towards the first tightened and then when you tighten the rest the first one ends up way overtorqued. That's how the assembly gets warped, the wheel bends the rotor as it is pulled down. I've had to deal with torque induced vibration after dummies have tightened wheels down starting at one and going around the circle, I just unscrew all the lugs a half turn and then take them back down in a star pattern to the proper torque. If you own a Honda and, I'm sure, some other small cars you might as well go ahead and junk the rotors if they are tightened wrong, you'll get brake pedal pulsation within a hundred miles.

 

[RoyJackson]

When I worked at a Porsche repair shop, we always tightened (but not too tight) with a socket/breaker bar first, then did a progressive torque. That is, torque (using a criss/cross pattern) to 50 or 60% of the final torque, then torque to specs (again, criss/cross pattern). I couldn't find the spec, but memory tells me it's 85 or 90 ft-lbs. This was applicable on both cast aluminum and the forged aluminum wheels.

 

[JD4610]

Torque value is 100lb/ft per the 2002 Ranger shop manual. Remember this is for clean, dry threads. You should reduce torque value approx 20 percent if anti-seize or other lubricants are used.

 

[normde2001]

I think 100ft/lbs. is about what an average man will exert with a standard lug wrench without breaking a sweat. That happens to be what the low setting on my impact wrench is. Works good for me, I can put them on with the impact wrench and still remove with the jack handle if necessary.

 

[Junkman]

</font><font color="blue" class="small">( Torque value is 100lb/ft per the 2002 Ranger shop manual. Remember this is for clean, dry threads. You should reduce torque value approx 20 percent if anti-seize or other lubricants are used. )</font>

why the reduction in torque????? dry or lubricate threads... 100 ft pounds is still the same..... Is the 20% what the book says????? Doesn't make any sense to me..... /forums/images/graemlins/confused.gif

 

[normde2001]

"Remember this is for clean, dry threads."
I have always wondered how, or if, friction was figured into torque values. Obviously, if you torque a rusted bolt with a torque wrench set at 100 ft/lbs., it will click at 100 due to friction, however the actual torque on the bolt will be far less than 100 ft/lbs. So, is torque correct on a dry bolt, (some friction), or on a lubricated bolt, (almost no friction).

 

[DavidJ]

Lubrication reduces the frictional drag on the fastener and therefore increases the true torque on the assembly. I agree with the 20% reduction in torque setting.

I hope you made sure not to allow any on the mating surface between the nut and wheel. That severely affects the torque. It also reduces the holding friction of the joint, possibly allowing loosening of the nut while in service.

 

[5030]

</font><font color="blue" class="small">( Torque value is 100lb/ft per the 2002 Ranger shop manual. Remember this is for clean, dry threads. You should reduce torque value approx 20 percent if anti-seize or other lubricants are used. )</font>

To everyone:

That's what I torqued them at. I removed the lugs I put never sieze on, cleaned the studs and nuts with brake cleaner and re-mounted the wheels.

My wife told me the vibration is gone. She is happy, I am happy. I paint marked the wheels with 100 foot pounds so I can remember. If she get a flat on the road, I hope the tireman will heed the torque setting too.

I think what happened is: She took the Ranger to the dealer at 12K for a front end alignment and balance. That is part of the warranty so it's free. I think they re-mounted the wheels with the old impact and never torqued them to specs. The vibration appeared just after she brought the Ranger home.

Again, thanks to everyone. I knew if I posted the problem, someone would have the answer. That's what makes this site the best place for information. /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif

 

[Junkman]

I have painted the rotor face where the alloy wheel meets it on every car since I had the problem of salt causing corrosion between the rotor and the wheel. I have never had any problem getting the wheels off ever since and I have never had a wheel come off or even loosen when I used never seize on the studs. Before never seize, people would use axle grease to keep the nuts from rusting to the studs. Some might not agree with this practice, but for me it works and that is what counts. Everyone is free to make their own decision as to how they will proceed for the future. There is always room for dissent and if anyone thinks that this method is not safe, then I would tell them not to do it. We are all responsible for our own decissions.... The Junkman

 

[JD4610]

</font><font color="blue" class="small">( why the reduction in torque????? dry or lubricate threads... 100 ft pounds is still the same..... Is the 20% what the book says????? Doesn't make any sense to me..... )</font>

Yes, 100 lb/ft is still the same, but what is happening to the fastener is not the same.

It is important to remember how a bolt or stud works. They work by stretching just slightly, like a rubber band. As you tighten the lug nut, you are actually stretching the stud toward the outside of the wheel, and it is the stud's wanting to spring back to it's original length that actually holds the rim to the hub.

What's important, as we all know, is that the stud can only stretch so far before it becomes damaged, and will no longer have the strength to spring back. So, we need a way to measure how far the bolt is stretching, so we don't go too far. That's what the torque specifications are for. As we tighten the nut, the stud is stretched and the farther it is stretched the more pressure is placed on the threads between the stud and nut, and also beween the nut and the rim. This pressure results in increasing friction as the nut is tightened, and thus an increasing amount of torque is required to continue turning the nut.

Somewhere, an engineer decided that a certain amount of torque was required to stretch the stud enough to sufficiently hold the wheel to the hub. When you put grease or other lube on the stud, you have now reduced the friction between the stud and nut, therefore, the stud will have to be stretched further before friction increases enough to meet the torque value, possibly exceeding the mechanical limits of the stud.

The 20% value is a generally recognized value for anti-seize. If you want to be technical, many engineering books will give exact figures based on the exact lubricant, type/style of fastener, and thread class, among others.

I'm sure there was a heck of a lot easier way of saying this, but I haven't gotten much sleep lately /forums/images/graemlins/blush.gif