Lug Nuts Max Torque?

[Bugsysiegals]

I seen a missing lug nut on my wife’s vehicle and so I just bought a Precision Instruments 1/2” Torque Wrench. I decided to check my Ram 1500 with 20” rims since I’d had the tires changed before Winter and the wrench went up to 175 ft. lbs. without the lugs moving at all.

I’m not sure how much farther it’ll go and I suspect it’s calibrated as it’s new but it makes me wonder how much is to much torque since these are spec’d at 130???

 

[cj7]

I seen a missing lug nut on my wife’s vehicle and so I just bought a Precision Instruments 1/2” Torque Wrench. I decided to check my Ram 1500 with 20” rims since I’d had the tires changed before Winter and the wrench went up to 175 ft. lbs. without the lugs moving at all.

I’m not sure how much farther it’ll go and I suspect it’s calibrated as it’s new but it makes me wonder how much is to much torque since these are spec’d at 130???

“went up to 175 ft lbs without the lug nuts moving” - where you tightening or loosening?

Torque to loose nuts is usually greater than the torque that tightened them, but the best thing to do is jack it, loosen them all, and retorque. Very likely your tire store tightened them with an impact, and over did it by a fair margin. Over tight lug nuts will fatigue the alloy seats and over time, possibly cause cracking.

 

[stevj]

FSM shows wheel nut torque should be set to 130 Ft-Lbs dry.

Steve

 

[Jako]

“went up to 175 ft lbs without the lug nuts moving” - where you tightening or loosening?

Torque to loose nuts is usually greater than the torque that tightened them, but the best thing to do is jack it, loosen them all, and retorque. Very likely your tire store tightened them with an impact, and over did it by a fair margin. Over tight lug nuts will fatigue the alloy seats and over time, possibly cause cracking.

Thanks for your posting. Raised my level of interest. Looking for some verification on the internet and came across the below web page. Based on the article it "takes less" with a BUT, "Of course, this doesn't account for what might happen in the period between installation and removal of a nut or bolt: Rust, corrosion, threads seizing, and the like."

Why it Takes Less Torque to Loosen a Bolt Than to Tighten It

It may not feel like it when you're fighting with a stuck or stubborn bolt, but it's true.

www.roadandtrack.com

 

[Malodave]

I picked up a 130 ft/lb torque stick from Ebay. This allows me to use
an Air or Electric Impact Gun and not over tighten the lug nuts.

$18.30 with free shipping

Brown 130 ft/lb (175 Nm 1/2" Chrome-Molly 7" Extension Bar Torque Limiting Stick | eBay

Lower Power Cordless Will Recoil but May Never Reach Proper Torque. Higher Power Will Over Torque as The Stick Never Rebounds. Properly Rated for Use With ½" Air Impact Having 300 - 500 Ft. Lb. If Necessary Turn Down Maximum Speed to Strike Less Than 1000 Impacts Per Minute.

www.ebay.com

Malodave

 

[Richard320]

Technically the maximum torque you can apply is about 1/8 turn before the stud breaks

When I worked at a dealership, once in a while someone would get a car in with a lugnut that they couldn't loosen. Then there'd be a sort of contest, where guys would line up to see whose impact gun was strongest.

 

[cj7]

Thanks for your posting. Raised my level of interest. Looking for some verification on the internet and came across the below web page. Based on the article it "takes less" with a BUT, "Of course, this doesn't account for what might happen in the period between installation and removal of a nut or bolt: Rust, corrosion, threads seizing, and the like."

Why it Takes Less Torque to Loosen a Bolt Than to Tighten It

It may not feel like it when you're fighting with a stuck or stubborn bolt, but it's true.

www.roadandtrack.com

thx. I’ve seen articles on both sides of this, but hadn’t seen that one.

Yes, in the lab, the torque measured to loosen right after tightening would be less, by a little, makes sense. In the real world, that may be the case, for those reasons as well as elasticity of stretched/compressed materials. But like you said, the environmental factors the article noted were not accounted for.

Fun fact, most air impact wrenches are purposefully designed to generate more loosening torque than tightening...

Anyway, an interesting read, thx.