using a torque wrench to tighten lug nuts

[GYPSY400]

Re: using a torque wrench to tighten lung nuts

Torque wrench is the right way to put on tires...torqued to spec. A torque stick on an impact is ok. Anyone who just bangs things home with an impact or breaker bar is dumb.

I agree.. I use a torque wrench on every wheel I install, be it a car, trailer, my atv etc.. For the time it takes it helps me sleep at night.

 

[GCncsuHD]

I totally agree, except on one point- some cars REQUIRE anti-seize on not only the threads, but other parts of the nut, and the torque spec is given with that in mind - if you have anything even slightly exotic, RTFM!!

Keyword some. The truth is 95% of cars out there have a torque rating specified for dry threads. Any that took lubricated threads into consideration should have it specified in the manual, even many shop torque specification charts will have asterisks beside the rating.

For example the two piece flat washer lugs on Ford trucks require a drop of oil between the nut and the washer, but explicitly state that no oil should contact the threads.

Bolt size Wheel lug nut torque*
Nm Lb-ft
M14 x 1.5 200-225 150-165
* Torque specifications are for nut and bolt threads free of dirt and
rust. Use only Ford recommended replacement fasteners.

On all two-piece flat wheel nuts,
apply one drop of motor oil between
the flat washer and the nut. Do not
apply motor oil to the wheel nut
threads or the wheel stud threads

Depending on the type of lubricant used you may need to decrease the torque anywhere from 20-50%. And the relationship between torque and the tension is not a linear one, a 20% reduction in torque required due to thread lubrication, but still torqued to the same value can double the tension applied to the fastener, quickly and easily going beyond the yield stress of the material.

 

[Thruxton]

Keyword some. The truth is 95% of cars out there have a torque rating specified for dry threads. Any that took lubricated threads into consideration should have it specified in the manual, even many shop torque specification charts will have asterisks beside the rating.

For example the two piece flat washer lugs on Ford trucks require a drop of oil between the nut and the washer, but explicitly state that no oil should contact the threads.

My point exactly!

 

[GCncsuHD]

My point exactly!

 

[P_I_Torque]

I totally agree, except on one point- some cars REQUIRE anti-seize on not only the threads, but other parts of the nut, and the torque spec is given with that in mind - if you have anything even slightly exotic, RTFM!!

Kudos! Very true, point taken, I stand corrected . I spend a lot of time in shops with customers who are generally not working with vehicles that require lubrication, so it's become my knee jerk reaction when speaking in generalities on this topic.

The torque specification is related to clamping force which requires a friction type hold to keep the assembly together. However, when you have very rusty or mauled threads, the friction generated far exceeds the calculated normal value. So lube it up, right? Nope, either get new lugs or replace the stud. You can probably do an entire wheel for less than $10.00 on most vehicles. This will ensure the calculated torque value will obtain the required clamping force, and the wheels on the buss keep going "round and round"

 

[nuklbstr83]

Re: using a torque wrench to tighten lung nuts

I'm not going to ruin the calibration of my torque wrench on lug nuts.

uhhhh... really?

 

[mrjaw14]

I keep a cheap HF 1/2" drive torque wrench for my lug nuts. I figure it'll get 'em close enough. Having said that, I only have cheap HF torque wrenches and a beam style craftsman. as a DIY I haven't really have to have a nice torque wrench...yet. I plan on getting one though if I ever have to get into something really serious like a head or anything that the "close enough" mentality isnt good enough.

 

[Awfulcanawful]

I tighten mine until they loosen. At that point I back up half of a turn.

 

[ezriderga]

I always use a torque wrench to tighten lug nuts on my vehicles. One has steel wheels and the other has alloy wheels.

 

[Antique Engine]

Re: using a torque wrench to tighten lung nuts

I'm not going to ruin the calibration of my torque wrench on lug nuts.

My torque wrench is vain like that too. But I can wrap it in a towel and tell it that we are torquing head bolts on a Ferrari and it doesn't get its feelings hurt like if it knew we were torquing lug nuts.

Seriously though, buy good tools, care for them properly, and it doesn't matter if you're torquing lug nuts on a Yugo or rocket boosters on the space station. It's a fastener that you turn until its properly tightened.