Here is a real conundrum.

Lets say i am finishing a job on my truck that required me to remove my wheels. I have a pneumatic impact wrench in my hand, attached to a 155 gallon tank with a compressor on top. How high should i set the PSI on the compressor to torque the lug nuts on? (assuming i dont have a torque wrench to check)

At first i thought they would be equal, but the more i think about it the less sense it makes. PSI is a rating on pressure and Ft lbf is a measure of torque or force applied to a pivot point, so i dont think that you can convert from one to the other. But that can be right, shops use impact wrenches all the time and i doubt that even the best shops check EVERY.....SINGLE....bolt?

Anyways i'm just bored here at work and thought that someone here has got to understand this...thx

 

google>>>>>

 

No, a lot of shops use torque bars or torque sticks to save time.

http://www.sjdiscounttools.com/accat4.html

 

The impact wrench should have a chart. It varies from wrench to wrench.

 

shops usually just use an impact to tighten the bolts and dont check the torque of the nuts, for tires ive noticed that most of the shops used torque wrenches. personally i never use a torque wrench for wheels i just tighten them around 100 ft lbs

 

I run 90 psi on my impact a few different kinds . With never seize I snug them up I have never broke a stud or had a wheel come loose .

I have never torqued a lug nut But I also torque the wheel bearing lock nut.

Torque wrenches are cheap How can you not have one???

 

i've always gone by feel on my rigs and never had issues. But when i worked at a shop a ran on the lug nuts with a 40lbs impact torque stick. Then torqued with a torque wrench to factory spec and with a paint pen initialed the back of the tire just in case.

 

Yeah i tried google and that didnt produce good results. I just thought i would toss a new thread up and see what people thought, not really all that important. I own 2 torque wrenches and only use them on things that would need it, such as engine and suspension compents. I was just simplify the senario, usually for lug nuts i use around 90-100psi which has worked so far.

 

air tools are made to run at about 90 psi. if you're worried i would use the torque wrench. don't over tighten them and you certainly don't want to under tighten them. should be around 80-90 ft lbs. better to be sure. you said you only use them when it's something that really needs it. tires are important to keep on the car

 

here is something I found on google....maybe it will help
Killowatts to Horsepower:

HP --> KW:
* Horsepower x 0.746 = KW's
eg 200hp x 0.746 = 149.2KW's

KW --> HP:
* KW x 1.34 = Horsepower
eg 149.2kw x 1.34 = 200hp

Newton metre's of torque to Pounds per feet

Nm --> lb
* Nm x 0.74 = lb ft
eg. 143nm x 0.74 = 105.80lb ft

lb --> Nm
* lb ft x 1.36 = Nm
eg. 105.80lb ft x 1.36 = 143nm>

Kilopascal to PSI (pounds per square inch)

kPa --> PSI
* kPa x 0.145 = psi
eg. 100kPa x 0.145 = 14.5psi

PSI --> kPa
* PSI x 6.98 = kPa
eg. 150psi x 6.98 = 1047kPa

Litres to Gallons (Flow)

litres/min --> gallons/min
* litres/min x 0.2642 = gallons/min
eg. 40litres/min x 0.2642 = 10.568gallons/min

gallons/min --> litres/min
* gallons/min x 3.785 = litres/min
eg. 15gallons/min x 3.785 = 56.775

Kilometre to Miles

km --> mile
* km x 0.62 = mile

eg. 100km x 0.62 = 62miles

mile --> km
* mile x 1.61 = km
eg. 150miles x 1.61 = 241.5km