Reduce TORQUE to COMPENSATE for lubed threads?

[SR5]

Originally Posted By: SR5
So how / where do you measure the stretch?


On second reading, I think I got it. Do it to solid touching by hand, then watch the angle you move the T-bar to get the correct torque. Given the constant pitch of the thread, same angle or movement = same stretch.

Me ? I just do it firm by hand anyway. With lube a calibrated, Mk 1, slightly less firm.

 

[Shannow]

Originally Posted By: SR5
Originally Posted By: SR5
So how / where do you measure the stretch?


On second reading, I think I got it. Do it to solid touching by hand, then watch the angle you move the T-bar to get the correct torque. Given the constant pitch of the thread, same angle or movement = same stretch.

Me ? I just do it firm by hand anyway. With lube a calibrated, Mk 1, slightly less firm.


Yep, do the wheel snug, then back each one off and angle tighten.

(The turbines, we pull the flanges together, back them off, pull them "finger tight", which is 200ftlb, then tighten to 0.15% strain...calculate how much you need to stretch it, 6 tpi, and 360 degrees per pitch - stick a heating rod down the guts of the stud to expand them, rotate through the angle, and let cool...bingo, 0.15% strain).

 

[4WD]

Originally Posted By: Shannow
Originally Posted By: BrocLuno
With never seize I'd drop to 100 #'s. But you'll know when you start the nuts on by hand. Some studs are pretty rough and the never seize just fills in the pores/craters. They still feel like they have drag. On those I'd prolly go to the factory setting.

But if it feels smooth and buttery, you do not want to over stretch the stud and cause failure; so smooth feeling, 100 would be enough for me

And that's the way to know. Take a factory replacement stud and nut (new) and torque to spec w/o anything. Measure before and after. That's the stretch you are looking for. Now do it with never seize in increments. When you get the same stretch, that's your number. It's all about the stretch ...


Yes, all about the strain (stretch), and that's the safest, most reliable measure.

I'd do exactly as you suggest, then work out how far you rotate it after tight to get the stretch...then get in a habit of "angle tightening" to the angle that you've developed.

When I get a new car with a torquespec, I work out the angle on dry studs, then repeat that with the wheel brace after I've applied antisieze.


Back in the steel rim days … didn’t you always had some elastic strain energy stored through restoration force of the “steely” (and the wheel design) … Today, these machined aluminum rims butt up and there is pass through force … so, seems that would differ and the torque becomes more critical?

 

[Shannow]

Bolted joints are to be considered a bolt, within a spring. (at that point it's to be considered that the bolt is a spring in tension, while the bolted assembly becomes the spring in compression...hope that bit makes sense.

The design has to be such that under no operational forces does the joint become "loose"...in the turbines, it's steam trying to separate them, in a car, as you turn hard, the top bolts have to be tight enough that the wheel flange is still clamped sufficiently to the loosest (top) part of the hub...it's the shear forces between the wheel and the hub that do the work, the fasteners just hold them together tightly enough to do that.

By properly designing the "springs", you can reduce cyclic fatigue failures, fretting, and

Here's the old hose reel from the fence that just got replaced...it's 3C out there ATM BTW with bare feet.


You can see what you are referring to in the raised section around the bolt holes...flat steel against the hub, with only 1/8" of metal as the "spring" would have been too stiff with respect to the bolt itself, so they formed the steelies to crated a spring (think Belleville washer)...that's how you get the spring.

Alloy wheels are a lot less stiff, and less string, so typically the outer "spring" is effected by simply having a full thickness column of alloy from the base of the nut all the way through to the hub.

An arrangement like on the steelie would fatigue in short order.

 

[4WD]

Excellent examples ~ In my career, have seen lots of flanges being replaced by hub connections to take the bolt preload and in service dynamics away … They simply employ a locking taper to contain separation force, keep seal energized etc …
They can also (within reason) self align and don’t have the bolt pattern drama (orientation) …

 

[Silverado12]

Don't over think this, people. Take a 4 way and bear down on all 5 (or 6) with even an "feel" for the torque. FWIW semi truck lug nuts are 475# torque. In that situation you really need a torque wrench with a long handle to get them done right.

 

[andyd]

meh, I use a light coat of whatever is in the grease gun. Lug nuts or studs are tightened in 3 stages using the star pattern. The tool is the wrench in the car. my concern is getting the wheel off. Since I adopted ths routine, I can easily change a flat. I also haven't lost a wheel. either

 

[Trav]

The knee jerk reaction to clean the anti seize off is all well and good in climates with no salt sprayed a;ll over the roads but some guys have never experienced rotted lugs that are so rusted they break or very hard to get off so its understandable.
Reducing the torque slightly to compensate for lubed thread does not reduce the clamping force it just makes the lug easier to remove because its not rusted.

 

[doitmyself]

By Shannow:
Quote:
.it's the shear forces between the wheel and the hub that do the work


With steel wheels (alloy too?), is it wrong to lightly coat the hub and/or rotor hat with a lubricant to prevent corrosion? Will this negatively affect the shear forces you mention?

FYI, Permatex recommends not to adjust torque values using their anti seize. Recommendations are all over the place.

 

[SumpChump]

I ended up cleaning off the studs but wasnt able to clean the nuts. So I used 115 of 135 foot lbs. sure felt like more than my Camry at 76-80 foot lbs indeed. I was cringing. But 115 should be fine even with the wet threads I suppose. They were factory alloys btw for those wondering.

 

[Shannow]

Originally Posted By: doitmyself
With steel wheels (alloy too?), is it wrong to lightly coat the hub and/or rotor hat with a lubricant to prevent corrosion? Will this negatively affect the shear forces you mention?


I believe so...I wouldn't do it.

 

[supton]

Originally Posted By: Shannow
Originally Posted By: doitmyself
With steel wheels (alloy too?), is it wrong to lightly coat the hub and/or rotor hat with a lubricant to prevent corrosion? Will this negatively affect the shear forces you mention?


I believe so...I wouldn't do it.


Next time I pull wheels I'll snap a pic. I've long noticed what looks like rub marks at the interface, but never bothered to investigate. As in, any anti seize will be fully gone, and it's nice bright shiny metal left. Interesting, I might have to change practice on that one. I only recently picked up a 4lb deadblow to deal with stuck wheels, so I've long done what I could to prevent them from sticking in the first place.

I haven't measured but I swear that rear lugs are usually a bit more loose than fronts, despite being tightened to the same amount, on my FWD vehicles.

 

[turtlevette]

Originally Posted By: Shannow
Originally Posted By: doitmyself
With steel wheels (alloy too?), is it wrong to lightly coat the hub and/or rotor hat with a lubricant to prevent corrosion? Will this negatively affect the shear forces you mention?


I believe so...I wouldn't do it.


I had to coat my vette aluminum wheels with antiseze where they touch the rotor hat. The wheels were sticking and I couldn't get them off. I had to loosen all the lug nuts a couple turns and drive around the block to get them to break loose.

 

[willbur]

Originally Posted By: doitmyself
By Shannow:
Quote:
.it's the shear forces between the wheel and the hub that do the work


With steel wheels (alloy too?), is it wrong to lightly coat the hub and/or rotor hat with a lubricant to prevent corrosion? Will this negatively affect the shear forces you mention?

FYI, Permatex recommends not to adjust torque values using their anti seize. Recommendations are all over the place.


My can of Permatex AZ says to torque to the manufactures' specs- it doesn't mention adjusting torque. Puzzling. The owners manual for one of my cars says to apply AZ to the threads, but not to the cones that fit the wheel (perhaps the specified torque takes this into account). This got me thinking and a little research lead me to conclude applying AZ to bolt threads has little or no effect, but to reduce torque if AZ is applied under the bolt/fastener head. If it were me, I would apply some AZ to the studs for ease of wheel removal; but not to the cones, and torque to the specified value. Just my opinion.

Regarding applying AZ or grease to the rotor hat/hub, I too read some manufacturer recommending against it (don't remember where). But sometimes wheels are almost impossible to remove wo doing this. Rust on this surface may also lead to run out issues and brake shake.

 

[Trav]

I wish some of you guys worked on cars here in the salt belt. Rotors you have to cut off with a sawzall and air chisel, rotten studs and hubs that need to be replaced and wreck the wheel bearing pressing it out in the bargain, taking smoke wrenches to all sorts of stuff, its terrible and corrosion behind the alloy wheel that needs a whiz wheel to remove.


I smear a very thin coat of anti seize on the hub face before putting the rotor in and always a thin coat on the back of alloy wheels, never had an issue or lost a wheel in 45 yrs doing literally thousands this way.
Salt water spray gets into everything, it will rot the exhaust manifold right off the engine, rot the frame out and everything else under the vehicle then it moves upward into the body.

To each their own but I will keep using the never seize like always.

 

[supton]

I've only had one set of alloys but those darn things needed anti seize to prevent just that. They also needed retorquing and while that's not a pain I was left wondering about their real value to me.

My Camry's need anti seize around the hub center, it's a tight fit and they will stick with little time. May I should skip on the other hub-wheel interface on my steelies.

But it gets used liberally elsewhere. Up here there is a distinct value to breaking apart brake hardware on a new car and doing just that. Shoot, just realized, I've never done that on my old Camry. At least it has those screw holes to pop out the rotors--now that is a cool "invention". Assuming the threads don't strip.

Maybe the state should look into snow tire subsidies, taking the money from salt purchases and put it towards snow tire checks. They could "win" by extending bridge and overpass lifespans. Oh well.

 

[eljefino]

Originally Posted By: willbur
The owners manual for one of my cars says to apply AZ to the threads, but not to the cones that fit the wheel (perhaps the specified torque takes this into account). This got me thinking and a little research lead me to conclude applying AZ to bolt threads has little or no effect, but to reduce torque if AZ is applied under the bolt/fastener head.


Think about what happens when you snap a stud, you give it rotational energy it wasn't designed to take and it just shears. Anti-sieze on threads prevents this. If your running torque is way worse than it should be a little antisieze is a good idea.

But the friction of the acorn nut on the wheel keeps it from vibrating loose. If it galls to the wheel, it's still going to come off with enough oomph behind it, and you won't snap the stud.

 

[Ducked]

One of my uncertainties about torque wrenching is with the effect of technique on the standard "tighten nut until the specified torque is reached" instruction.

When I do that, the nut is usually still moving. Should I stop at that point (as the standard instruction seems to imply), or hold the torque at that level until rotation stops?

The former seems likely to vary, depending on how fast you tighten the nut.

The latter seems likely to be more reproducible, but also likely to get the nut a lot tighter.

This is using a beam-deflection wrench.

With the click-type, (which I don't have) you don't have the option of holding at the set torque value, but I think the rate at which you reach it must still influence the final tightness of the nut?

Admittedly I hardly ever torque dry fastners, where perhaps this effect of technique might be less, but I think it will still exist.

 

[Ducked]

Originally Posted By: turtlevette
Originally Posted By: Shannow
Originally Posted By: doitmyself
With steel wheels (alloy too?), is it wrong to lightly coat the hub and/or rotor hat with a lubricant to prevent corrosion? Will this negatively affect the shear forces you mention?


I believe so...I wouldn't do it.


I had to coat my vette aluminum wheels with antiseze where they touch the rotor hat. The wheels were sticking and I couldn't get them off. I had to loosen all the lug nuts a couple turns and drive around the block to get them to break loose.



Couldn't get antiseize here so I started using aluminium foil or polythene sheeting between wheel and hub after having to do the same thing (with speed bumps) a couple of times. Figured I'd damage the studs if I kept doing that.

Ordinary grease would probably work ok but might make a mess or melt off if overdone.