Torquing lug nuts to spec...

[rivermobster]

https://www.reddit.com/r/Justrolledintotheshop/comments/1273fip

 

[timstoy]

Professional you pay to work on your car!

 

[Chili Palmer]

I remember when I had that problem, but years of river life have taken care of that.

 

[counterpart7]

Oh boy. Good way to knock yourself out…

 

[RitcheyRch]

at least using a torque wrench and not an impact. Kudos for giving it the old college try.

 

[lbhsbz]

Math is hard.

60lbs at the end of a 24" lever creates 120lb.ft of torque.

 

[farmo83]

Listen to the Ron White bit about tires.

 

[LHC30]

Teach him to dead lift the wrench. Much better development and outcome. Lol

 

[DLow]

Teach him to dead lift the wrench. Much better development and outcome. Lol

Meh. My back would respectfully disagree. Poor kid needs a longer torque wrench.

 

[Icky]

Someone needs to teach that kid about gravity and how to use his body weight

 

[lbhsbz]

Meh. My back would respectfully disagree. Poor kid needs a longer torque wrench.

Poor kid needs to understand geometry.

Pulling back against a lever that’s more horizontal than it is vertical doesn’t do anything but stretch the torque wrench…lol.

Reminds me of that video with the idiot holding the ladder in the air trying to knock something off a shelf or whatever instead of just climbing the fucking ladder and grabbing it.

 

[Mandelon]

I usually just stand on the lug wrench. Am I supposed to be actually torquing those nuts to a specific number?

 

[rivermobster]

I usually just stand on the lug wrench. Am I supposed to be actually torquing those nuts to a specific number?

Depends...

How much do you weigh?

 

[lbhsbz]

I usually just stand on the lug wrench. Am I supposed to be actually torquing those nuts to a specific number?

That's actually the most precise way to do it...if you don't bounce. Multiply how fat you are by how long your lug wrench is, there's your torque value.

 

[OCMerrill]

Listen to the Ron White bit about tires.

The Lug nuts flew the fuck off....

Sears tire college equals Ron White's big ole fuckin building.

 

[TrollerDave]

120 lbs. Ahh, I remember 5th grade.

 

[Nordie]

Just cross thread, and give it 3 uga dugas...that ain't going nowhere

 

[PlumLoco]

WHY would any lug nut need to be that tight? Seems like a poor design.

 

[rivermobster]

WHY would any lug nut need to be that tight? Seems like a poor design.

WTF do you drive?? A Mini Cooper or something like that??

 

[TimeBandit]

A blind man could see the problem.

His pickleball shoes are slipping.

 

[PlumLoco]

WTF do you drive?? A Mini Cooper or something like that??

At 6'6" I've never even thought about driving a Mini anything. And I'm so old I grew up with left handed lug nuts on the left hand side of my Mopars. Seems like i never had a lug nut come loose. I guess 50-60 lbs was enough.

 

[rivermobster]

At 6'6" I've never even thought about driving a Mini anything. And I'm so old I grew up with left handed lug nuts on the left hand side of my Mopars. Seems like i never had a lug nut come loose. I guess 50-60 lbs was enough.

Oh yeah...

Those were fun if you didn't know better!

50bl was probably plenty on a 14-15 inch steel wheel.

On a new 19 or 20 inch truck wheel? The bigger studs require quite a bit more torque.

 

[ltbaney1]

Just cross thread, and give it 3 uga dugas...that ain't going nowhere

a cross thread is a tight thread!

 

[ltbaney1]

WHY would any lug nut need to be that tight? Seems like a poor design.

torque spec on my 1500 silverado is 140 ftlbs.

 

[PlumLoco]

Interesting . . . so lugs need tobe tighter because the wheel is bigger? Isnt it still a 5 on 4 or 5 bolt pattern? Wouldn't a 20 be spinning slower than a 14-15" near the center?

 

[TimeBandit]

Interesting . . . so lugs need tobe tighter because the wheel is bigger? Isnt it still a 5 on 4 or 5 bolt pattern? Wouldn't a 20 be spinning slower than a 14-15" near the center?

it's also a bigger "lever" when side loads are applied. a 14" rim with large sidewall tires must be easier on the hub than a 20" with low profile tires.

 

[rivermobster]

Interesting . . . so lugs need tobe tighter because the wheel is bigger? Isnt it still a 5 on 4 or 5 bolt pattern? Wouldn't a 20 be spinning slower than a 14-15" near the center?

Good questions. As you can see in the vid, it's Definitely not an old school 5 lug configuration.

Lemme sit in front of a keyboard to try and answer mote thoroughly.

I'll be back....

 

[spectra3279]

I thought you took them to torque, then backed off 1/4 turn

 

[Nanu/Nanu]

Kid needs stickier shoes. Wipe them off with a damp rag or something! Haha he'll.figure it out soon enough

 

[Nordie]

Still wondering what this guy torqued his wheels to? I'm thinking 1 uga dugga

 

[LazyLavey]

My back hurts just watching that


this is why you need proper lug torque

Tire Pops Off Truck, Causing Car to Soar into the Air Along Calif. Freeway: See the Shocking Video

Police say no one was seriously injured in a stunning crash on the Ronald Reagan Freeway in the Chatsworth neighborhood of Los Angeles

www.yahoo.com

 

[2Driver]

Wouldn’t just a 3’ section of pipe on the end of the wrench solve the problem?

 

[rivermobster]

Interesting . . . so lugs need tobe tighter because the wheel is bigger? Isnt it still a 5 on 4 or 5 bolt pattern? Wouldn't a 20 be spinning slower than a 14-15" near the center?

Ok, so here we go...

First and foremost, fastener torque is determined by the fastener being used.

As you can see, there are differences in torque values based on material, fastener size, thread pitch, density (hardness). And metric fasteners are a whole different story, as they have all kinna different thread pitches!

So how is a given fastener determined? That's for people with engineering degrees to decide. Not for simpletons like me. Just image the variables though...

Rim size, tires size, braking force (vacuum, hydro boost, air, electric), rotor size, caliper size, vehicle weight (loaded, unloaded, towing), vehicle weight capacity...

Suspension? Live axle? A-arm? Strut? Engine and powertrain? 1000ft lb of torque diesel? Or a 500ft lb of torque gas engine?

Will the fastener survive an impact (traffic accident)? How about a pot hole? How about the bigger rims and tires pretty much everyone swaps the stock wheels out for? Different wheel backspacing (offset) does a number on how much lateral torque is applied to the hub (wheel studs and lug nuts)! There are a million things that can go wrong when swapping out stock wheels and tires. It's always best to use a professional like @RVRKID rather than what some "expert" on a forum tells you!

A shit ton of engineering goes into a modern vehicle. Way more than can be typed out here. There is a good reason the new 1/2 tons have a much higher load capacity than 1/2 tons of the past, and it's not just because they stuffed a few more leafs in the rear springs! Everything has been redesigned over the years, including, you guessed it...

The lowly lug nut.

Wheel rotation speed may have something to do with what wheel fasteners are used, but there are many more additional factors than just that.

I'm sure @lbhsbz can expand on this even further, when it comes to braking forces, when he finds time in his day.

 

[lbhsbz]

Ok, so here we go...

First and foremost, fastener torque is determined by the fastener being used.

View attachment 1214443

As you can see, there are differences in torque values based on material, fastener size, thread pitch, density (hardness). And metric fasteners are a whole different story, as they have all kinna different thread pitches!

So how is a given fastener determined? That's for people with engineering degrees to decide. Not for simpletons like me. Just image the variables though...

Rim size, tires size, braking force (vacuum, hydro boost, air, electric), rotor size, caliper size, vehicle weight (loaded, unloaded, towing), vehicle weight capacity...

Suspension? Live axle? A-arm? Strut? Engine and powertrain? 1000ft lb of torque diesel? Or a 500ft lb of torque gas engine?

Will the fastener survive an impact (traffic accident)? How about a pot hole? How about the bigger rims and tires pretty much everyone swaps the stock wheels out for? Different wheel backspacing (offset) does a number on how much lateral torque is applied to the hub (wheel studs and lug nuts)! There are a million things that can go wrong when swapping out stock wheels and tires. It's always best to use a professional like @RVRKID rather than what some "expert" on a forum tells you!

A shit ton of engineering goes into a modern vehicle. Way more than can be typed out here. There is a good reason the new 1/2 tons have a much higher load capacity than 1/2 tons of the past, and it's not just because they stuffed a few more leafs in the rear springs! Everything has been redesigned over the years, including, you guessed it...

The lowly lug nut.

Wheel rotation speed may have something to do with what wheel fasteners are used, but there are many more additional factors than just that.

I'm sure @lbhsbz can expand on this even further, when it comes to braking forces, when he finds time in his day.

Copied and pasted from another thread....

Understand first that the idea behind tightening a fastener correctly is to get it to stretch a certain amount. Using force to estimate this amount is archaic and unreliable...but works reasonably well on clean, new fasteners and threads....any deviation from clean and new with the specified surface treatment...and all bets are off. This is why we are seeing more and more torque specification moving to a relatively low torque value and then adding a "torque angle"...example: 25lb/ft + 90° + 90°.

How you use a torque wrench is also a major factor....if I have an M10 bolt with a torque spec of 45lb/ft and I happen to stop turning my torque wrench before it clicks...say around 38 lb/ft, then ratchet it back to get a better angle and attempt to start turning again, there is a good chance that torque wrench will click (or otherwise indicate that 45lb/ft has been achieved) before the fastener starts to turn again. This doesn't mean we've tightened the fastener correctly...because we haven't. Go to "snug" and then we must arrive at the final torque value in a smooth and consistent motion of the torque wrench. The torque angle method removes this source of error. Bouncing on the torque wrench and hearing it click doesn't work either.

If I have an M10x1.0 (10mm thread major diameter, 1.0mm thread spacing) and I want that bolt to stretch exactly 0.5mm, a torque angle is the most reliable way to have that happen. 25lb/ft simply snugs up the assembly to arrive fairly close to zero clearance between mating parts, but with little to no bolt stretch at that point. If we turn a fastener 1/2 turn and that fastener has 1.0mm thread spacing, that bolt will get 0.5mm longer when we're done, without question (if threads don't fail due to degradation). It doesn't matter how crusty, or how much lube or loctite (loctite is a lube before it cures), or how many times we stop and start again turning the fastener, the bolt stretch will be the same.

The correct fastener stretch is critical for not only keeping the bolt from falling out or breaking or stripping threads, but also because in the effort to increase fuel economy and make up for all the added weight from safety bullshit and technology being added to cars, manufactures are designing things to be as light weight as possible. Many components of a modern engine are considered structural, and the appropriate joint integrity/clamp force is critical to making everything live. Rumors were spread years ago on the GM 3.1/3.4/3.8L V6 engines that overtorque on the intake bolts would distort the block and lead to premature main bearing failure after intake manifold gaskets or heads gaskets were replaced. I don't know if there was any truth to it, but had the technician prepared the threads and torqued the bolts to spec, that scenario could have been positively ruled out as to the cause of failure.

Bolts in most cases are not designed to carry any cyclic loads....the bolt creates the appropriate clamp force between multiple parts, and that clamp carries the load. Any time a bolt is subject to cyclic loading, it will be at risk of fatigue failure....which is why exhaust manifold bolts break so often (or more often than other bolts). Most broken fasteners are due to undertightening rather than overtightening...because the undertightened fastener did not clamp the parts together properly in order to create a joint strong enough to deal with the loads incurred, so the bolt ends up carrying the cyclic loading and eventually fails.

I very rarely torque anything made of plastic...I have sort of figured out over the years how much a given size bolt needs to stretch, from years of using a torque wrench. Example...when I build calipers that have M7 bolts holding the inner and outer half together, using 3 different torque wrenches, I get about 1/2 turn on each bolt after the fastener is snug. I don't waste time with a torque wrench anymore, I simply snug everything down with a low torque air ratchet, then turn each bolt 1/2 turn, either using and impact wrench with marks on my socket to reference, or using a ratchet that I point straight up before I start and and I stop when it's pointed straight down. My method is more accurate than using a torque wrench.

The attached chart is a good starting point, but use it as a tool to determine how much stretch you're trying to achieve from a given fastener, and then just stretch them all that much. I like this chart because it goes into prevailing torque fasteners, as well as standard stuff, and has clamp load data as well. When designing something or making something in your garage...many of us way overestimate the fastener requirements, which just adds weight. A 1/4-20 bolt will create over 1000lbs of clamp. Ever feel a bit sketchy lifting a fully dressed BBC by one of those adapter plates on the carb studs?….don’t. If the threads are in good shape, those 4 little 5/16” studs can support in excess of 11K lbs.

Use of extensions will change things...especially 1/4" extensions that act like a torsion bar spring. You'll need to increase your torque value as you add extension length to your tool....how much?...who knows. That takes us back to the torque angle method.
Consult the service manual, consult the charts, and use your judgement. For critical fasteners, follow the rules. I had a friend who's husband and father in law attempted to replace a harmonic balancer on her Oldsmobile (shortstar engine) and without the proper tools, just tightened the balancer bolt the best they could. It destroyed the engine a few weeks later. The woodruff key is designed to align things...that's it. It is not designed to carry any sort of load. They failed to create the appropriate joint, or the appropriate clamp force between the balancer, lower timing gear, and crank shaft, which resulted in the shearing of the woodruff key that times the lower timing chain gear, and 24 bent valves.
What is a critical fastener and what is not?...that's tough to determine sometimes.

 

[rivermobster]

Copied and pasted from another thread....

Understand first that the idea behind tightening a fastener correctly is to get it to stretch a certain amount. Using force to estimate this amount is archaic and unreliable...but works reasonably well on clean, new fasteners and threads....any deviation from clean and new with the specified surface treatment...and all bets are off. This is why we are seeing more and more torque specification moving to a relatively low torque value and then adding a "torque angle"...example: 25lb/ft + 90° + 90°.

How you use a torque wrench is also a major factor....if I have an M10 bolt with a torque spec of 45lb/ft and I happen to stop turning my torque wrench before it clicks...say around 38 lb/ft, then ratchet it back to get a better angle and attempt to start turning again, there is a good chance that torque wrench will click (or otherwise indicate that 45lb/ft has been achieved) before the fastener starts to turn again. This doesn't mean we've tightened the fastener correctly...because we haven't. Go to "snug" and then we must arrive at the final torque value in a smooth and consistent motion of the torque wrench. The torque angle method removes this source of error. Bouncing on the torque wrench and hearing it click doesn't work either.

If I have an M10x1.0 (10mm thread major diameter, 1.0mm thread spacing) and I want that bolt to stretch exactly 0.5mm, a torque angle is the most reliable way to have that happen. 25lb/ft simply snugs up the assembly to arrive fairly close to zero clearance between mating parts, but with little to no bolt stretch at that point. If we turn a fastener 1/2 turn and that fastener has 1.0mm thread spacing, that bolt will get 0.5mm longer when we're done, without question (if threads don't fail due to degradation). It doesn't matter how crusty, or how much lube or loctite (loctite is a lube before it cures), or how many times we stop and start again turning the fastener, the bolt stretch will be the same.

The correct fastener stretch is critical for not only keeping the bolt from falling out or breaking or stripping threads, but also because in the effort to increase fuel economy and make up for all the added weight from safety bullshit and technology being added to cars, manufactures are designing things to be as light weight as possible. Many components of a modern engine are considered structural, and the appropriate joint integrity/clamp force is critical to making everything live. Rumors were spread years ago on the GM 3.1/3.4/3.8L V6 engines that overtorque on the intake bolts would distort the block and lead to premature main bearing failure after intake manifold gaskets or heads gaskets were replaced. I don't know if there was any truth to it, but had the technician prepared the threads and torqued the bolts to spec, that scenario could have been positively ruled out as to the cause of failure.

Bolts in most cases are not designed to carry any cyclic loads....the bolt creates the appropriate clamp force between multiple parts, and that clamp carries the load. Any time a bolt is subject to cyclic loading, it will be at risk of fatigue failure....which is why exhaust manifold bolts break so often (or more often than other bolts). Most broken fasteners are due to undertightening rather than overtightening...because the undertightened fastener did not clamp the parts together properly in order to create a joint strong enough to deal with the loads incurred, so the bolt ends up carrying the cyclic loading and eventually fails.

I very rarely torque anything made of plastic...I have sort of figured out over the years how much a given size bolt needs to stretch, from years of using a torque wrench. Example...when I build calipers that have M7 bolts holding the inner and outer half together, using 3 different torque wrenches, I get about 1/2 turn on each bolt after the fastener is snug. I don't waste time with a torque wrench anymore, I simply snug everything down with a low torque air ratchet, then turn each bolt 1/2 turn, either using and impact wrench with marks on my socket to reference, or using a ratchet that I point straight up before I start and and I stop when it's pointed straight down. My method is more accurate than using a torque wrench.

The attached chart is a good starting point, but use it as a tool to determine how much stretch you're trying to achieve from a given fastener, and then just stretch them all that much. I like this chart because it goes into prevailing torque fasteners, as well as standard stuff, and has clamp load data as well. When designing something or making something in your garage...many of us way overestimate the fastener requirements, which just adds weight. A 1/4-20 bolt will create over 1000lbs of clamp. Ever feel a bit sketchy lifting a fully dressed BBC by one of those adapter plates on the carb studs?….don’t. If the threads are in good shape, those 4 little 5/16” studs can support in excess of 11K lbs.

Use of extensions will change things...especially 1/4" extensions that act like a torsion bar spring. You'll need to increase your torque value as you add extension length to your tool....how much?...who knows. That takes us back to the torque angle method.
Consult the service manual, consult the charts, and use your judgement. For critical fasteners, follow the rules. I had a friend who's husband and father in law attempted to replace a harmonic balancer on her Oldsmobile (shortstar engine) and without the proper tools, just tightened the balancer bolt the best they could. It destroyed the engine a few weeks later. The woodruff key is designed to align things...that's it. It is not designed to carry any sort of load. They failed to create the appropriate joint, or the appropriate clamp force between the balancer, lower timing gear, and crank shaft, which resulted in the shearing of the woodruff key that times the lower timing chain gear, and 24 bent valves.
What is a critical fastener and what is not?...that's tough to determine sometimes.

Yeah. What he pasted! ^^^

 

[SBMech]

"Rumors were spread years ago on the GM 3.1/3.4/3.8L V6 engines that overtorque on the intake bolts would distort the block and lead to premature main bearing failure after intake manifold gaskets or heads gaskets were replaced."

That warning is straight out of the FSM....

 

[PlumLoco]

Copied and pasted from another thread....

Understand first that the idea behind tightening a fastener correctly is to get it to stretch a certain amount. Using force to estimate this amount is archaic and unreliable...but works reasonably well on clean, new fasteners and threads....any deviation from clean and new with the specified surface treatment...and all bets are off. This is why we are seeing more and more torque specification moving to a relatively low torque value and then adding a "torque angle"...example: 25lb/ft + 90° + 90°.

How you use a torque wrench is also a major factor....if I have an M10 bolt with a torque spec of 45lb/ft and I happen to stop turning my torque wrench before it clicks...say around 38 lb/ft, then ratchet it back to get a better angle and attempt to start turning again, there is a good chance that torque wrench will click (or otherwise indicate that 45lb/ft has been achieved) before the fastener starts to turn again. This doesn't mean we've tightened the fastener correctly...because we haven't. Go to "snug" and then we must arrive at the final torque value in a smooth and consistent motion of the torque wrench. The torque angle method removes this source of error. Bouncing on the torque wrench and hearing it click doesn't work either.

If I have an M10x1.0 (10mm thread major diameter, 1.0mm thread spacing) and I want that bolt to stretch exactly 0.5mm, a torque angle is the most reliable way to have that happen. 25lb/ft simply snugs up the assembly to arrive fairly close to zero clearance between mating parts, but with little to no bolt stretch at that point. If we turn a fastener 1/2 turn and that fastener has 1.0mm thread spacing, that bolt will get 0.5mm longer when we're done, without question (if threads don't fail due to degradation). It doesn't matter how crusty, or how much lube or loctite (loctite is a lube before it cures), or how many times we stop and start again turning the fastener, the bolt stretch will be the same.

The correct fastener stretch is critical for not only keeping the bolt from falling out or breaking or stripping threads, but also because in the effort to increase fuel economy and make up for all the added weight from safety bullshit and technology being added to cars, manufactures are designing things to be as light weight as possible. Many components of a modern engine are considered structural, and the appropriate joint integrity/clamp force is critical to making everything live. Rumors were spread years ago on the GM 3.1/3.4/3.8L V6 engines that overtorque on the intake bolts would distort the block and lead to premature main bearing failure after intake manifold gaskets or heads gaskets were replaced. I don't know if there was any truth to it, but had the technician prepared the threads and torqued the bolts to spec, that scenario could have been positively ruled out as to the cause of failure.

Bolts in most cases are not designed to carry any cyclic loads....the bolt creates the appropriate clamp force between multiple parts, and that clamp carries the load. Any time a bolt is subject to cyclic loading, it will be at risk of fatigue failure....which is why exhaust manifold bolts break so often (or more often than other bolts). Most broken fasteners are due to undertightening rather than overtightening...because the undertightened fastener did not clamp the parts together properly in order to create a joint strong enough to deal with the loads incurred, so the bolt ends up carrying the cyclic loading and eventually fails.

I very rarely torque anything made of plastic...I have sort of figured out over the years how much a given size bolt needs to stretch, from years of using a torque wrench. Example...when I build calipers that have M7 bolts holding the inner and outer half together, using 3 different torque wrenches, I get about 1/2 turn on each bolt after the fastener is snug. I don't waste time with a torque wrench anymore, I simply snug everything down with a low torque air ratchet, then turn each bolt 1/2 turn, either using and impact wrench with marks on my socket to reference, or using a ratchet that I point straight up before I start and and I stop when it's pointed straight down. My method is more accurate than using a torque wrench.

The attached chart is a good starting point, but use it as a tool to determine how much stretch you're trying to achieve from a given fastener, and then just stretch them all that much. I like this chart because it goes into prevailing torque fasteners, as well as standard stuff, and has clamp load data as well. When designing something or making something in your garage...many of us way overestimate the fastener requirements, which just adds weight. A 1/4-20 bolt will create over 1000lbs of clamp. Ever feel a bit sketchy lifting a fully dressed BBC by one of those adapter plates on the carb studs?….don’t. If the threads are in good shape, those 4 little 5/16” studs can support in excess of 11K lbs.

Use of extensions will change things...especially 1/4" extensions that act like a torsion bar spring. You'll need to increase your torque value as you add extension length to your tool....how much?...who knows. That takes us back to the torque angle method.
Consult the service manual, consult the charts, and use your judgement. For critical fasteners, follow the rules. I had a friend who's husband and father in law attempted to replace a harmonic balancer on her Oldsmobile (shortstar engine) and without the proper tools, just tightened the balancer bolt the best they could. It destroyed the engine a few weeks later. The woodruff key is designed to align things...that's it. It is not designed to carry any sort of load. They failed to create the appropriate joint, or the appropriate clamp force between the balancer, lower timing gear, and crank shaft, which resulted in the shearing of the woodruff key that times the lower timing chain gear, and 24 bent valves.
What is a critical fastener and what is not?...that's tough to determine sometimes.

My son just started working at a Ford dealership, fresh out of a local jr. college 2 yr auto mechanic program. He has worked for a Lube & Tune place for a year already, but I doubt these kinds of fundamentals were covered so simply and so completely. Thank you for posting it.

 

[lbhsbz]

"Rumors were spread years ago on the GM 3.1/3.4/3.8L V6 engines that overtorque on the intake bolts would distort the block and lead to premature main bearing failure after intake manifold gaskets or heads gaskets were replaced."

That warning is straight out of the FSM....

I was a dealer tech back then....nobody read the FSM lol

 

[SBMech]

Hilarious as this is....if he had to torque the wheel bearing nut....yea.

Ferd modern stuff is fucking brutal....this is from a 2008 F150.

4. Remove and discard the wheel hub nut.
^ To install, tighten to 400 Nm (296 lb-ft).

Newer stuff is even higher at 340lbs.

I have a $900 4' torque wrench...just for this bullshit....

 

[HydroSkreamin]

This one learned how to do it… part of passing the ritual for driving in our house.

She got them all.