1980 c10, Rally wheel lug nut torque...

[78 Chevyrado]

My impact wrench is good for 750 Ft lbs.  if i ran it till it quit turning, my rims and rotors would be trash.  for the correct procedures, impact wrenches are ONLY for removing fasteners, NOT tightening them, unless you have an unreliable torque stick.  i tighten mine up for 2 or 3 hits on the impact them finish them with the torque wrench.  on my old steel wheels, i did it by feel, till i thought i should stop, never had a problem.  on my new expensive aluminum wheels, i use a torque wrench every time.

couldn't find it in my GM manual.  my Haynes Book says:

5 lug - 1/2" and 7/16"  studs = 103 Ft. Lbs

6 Lug - 1/2" and 7/16" studs = 88 Ft. Lbs

8 Lug - 9/16" studs = 118 Ft. Lbs

[Captkaos]

you should never run a lug down with an impact.  Think about your wife driving her car and having a flat and trying to remove a wheel on the side of the road in the rain with that tiny lug wrench.  I caught a tire store pulling out a impact to tighten some aluminum wheels on one of my vehicles.  I stopped him prior and told him those are to be torqued down.  He said that was ridiculous.  I called the manager and asked if this was their normal procedure and he said yes, I think said well if you pull your vehicle in here and run them down and take them off we will ok (he insisted that it wasn't torquing them down to tight -it was a snap on a friend has and I know it will go to above 600 lb/ft).  He pulled his truck around, jacked it up and the guy pulled it off and put it back on, I think asked him to remove it with his tire tool like he would if he was stranded, this wasn't a small guy.  He struggled with it for a couple minutes put the tool back up and told the guy to torque the wheels down like I told him..

[big bear]

wow....some people amaze me

[big bear]

in that story i was referring too.

[Stewart G Griffin]

If this is a 1/2 ton with 5 lug wheels?   Then i think 35-75ft. lbs per lug is a good ballpark estimate?

[Stewart G Griffin]

SERIOUS UPDATE:

1) i don't want to let you know what i think about haynes/chilton/etc. manuals because i heard that if you don't have something nice to say, then you should say nothing.......


2) Now that we got that out of the way, it should be in section 3, "IN CASE OF EMERGENCY" section of the owner's manual:

And i was shocked:

For Five lugs 9/16" stud,  120 ft. lbs!!!

Five lug 1/2" stud,  100 ft. lbs!!!

i really was shocked----i thought 35lbs was normal for light trucks and cars?

[78 Chevyrado]

using an impact wont make a difference, AS LONG as when you go to torque it, it actually turns some more. It'll be the same torque value if the TQ wrench it accurate.  if however you go to tourque it and it doesnt turn any, but clicks, you got it too tight.  you can get the nuts run down any way you want as long as you dont go over the torque value you want, its something you have to have a feel for.

I used to do it all with the gun on my old wheels cuz i had those 2001 wheels with the plastic nuts that screwed down onto each lug.  so screw it, i wasnt doing 64 of em by hand. still had 32 to do though.  i was glad to be rid of those wheels, they looked good but were a pain to put back together, killed the hands.  


It doesnt matter what the truck is...  an s10, c10, c20, c30 or a honda civic.  the torque value is determined by the studs materials and size.  obviously aluminum wouldnt take what a steel stud would, etc...

if a honda civic came with 9/16 studs, the value would be somewhere around 100-120 ft lbs.

Here's a torque value table i got from my Bowman Fasteners Torque Chart for Grade 5 fasteners

for coarse Thread (DRY - no anti-seize)

1/4"   =  9 ft lbs
5/16" =  17 ft lbs
3/8"   =  31 ft lbs
7/16" =  50 ft lbs
1/2"   =  76 ft lbs
9/16"  =  110 ft lbs
5/8"   =  150 ft lbs
3/4"    = 265 ft lbs

for coarse thread (WITH anti sieze compound on threads)

1/4"   =  5 ft lbs
5/16"  =  10 ft lbs
3/8"   =  19 ft lbs
7/16"  =  30 ft lbs
1/2"   =  45 ft lbs
9/16"  =  66 ft lbs
5/8"   =  90 ft lbs
3/4"   =  160 ft lbs

fine thread studs and bolts are about 4% higher values than above.

fasteners should be tightened by holding the bolt still and tightening the nut.  if you have to tighten the bolt and not the nut, increase torque value by 20% (multiply by 1.20) to make up for torsional twists of the bolt shank.

so going by the bowman manual, the haynes book says way too much for 1/2" n 7/16 studs.  I trust bowman way more than i do haynes.  I couldn't find the values in my Chevy shop manual though...  wierd.

also, i didnt even catch in the haynes they said the SAME value for 7/16" and 1/2".  that right there says its wrong.

[Irish_Alley]

78 you just pointed out that a 3/4" stud gets 265 ft lbs but thats not even close to the limits of a impact. then you can weaken the stud by stretching it. i mean you can always keep turning a bolt till it snaps. but i guess this is kind of the same reason some people use oil filter wrenches to put a filter on. Not to mention aluminum wheels will crack very easy

[78 Chevyrado]

What I'm meaning is that running the lugs down and maybe 1 or 2 hits isnt going to tighten them down to the guns full capacity.  If you keep hitting the lugs with the gun until the gun can't turn them anymore, and its just hitting it without moving the lug nut, then you have reached the full torque the gun can put out.  that would obviously destroy the wheel and or studs.  i dont tighten them down on mine more than one or 2 hits, then i goto the TQ wrench.  When I do it that way, it still takes about 1/4 to 1/2 turn of the lug nut with the TQ wrench before it clicks, at the 110 ft lbs i put on my wheels, with the 9/16" studs.

[Captkaos]

I 100% agree with that method Kenny.  The experience I have seen is most shops don't do it that way.

[Irish_Alley]

yeah i can see it that way thats how i said i did mine slow till it hits then use a 4 way

[78 Chevyrado]

My old tire shop was extremely irritating, with my old steel wheels, i only let them slide because two of my wheels were screwed up anyway, but i complained each time and it was funny to watch them run around when i showed up.  i actually had an alignment done there ONCE only, and they screwed it up by leaving the adjusting sleeve totally loose on BOTH tie rod ends. i found em at home loose and took it back and man there were some people running around scared they were gonna get fired.  that manager was flipping out over that.   

Thats one reason I've come to like my current tire shop a lot.  they hit it with the impact just to run them down, and then another guy goes around TQ-ing them all with the TQ wrench (no TQ sticks).

Also helps they dont set my center caps on their face and use them as bowls to hold the nuts while they work.

my old tire shop would make me cringe sometimes the way they did it, i put up with it cuz i had the steel wheels, but the new aluminum wheels, they doin it right or i cause a scene that makes other customers leave...

they do me really good though, finally a decent tire shop, and through them found a great alignment shop too!  finally got my truck lined up ON-Spec.  they put the PSI and TQ i Want on my truck.  finally got my PSIs figured out, TQ figured out, and they must ONLY use the lug-centric adapters to balance them.

[PromiseKeeper]

My tire shop uses a torque wrench, and as a double check, another tech goes around the vehicle a second time to check them. They ask you to stop by after 100 miles to have it rechecked. I like that kind of attention to detail.