Studs and Lugs

[PbFut]

Newer truck to me, I don’t recall my other trucks having lug nuts so tight. I’ve not had one of these trucks for more than 25yrs. Recently picked up a 72 GMC ¾ ton. The lug nuts and studs appear newer, no rust, blackened studs, normal looking lug nuts. 8 Lug, appear to be 9/16, I think. I can’t recall how the previous trucks were, but this one has lug nuts that seem way too tight. Almost like the pitch is ever so slightly off. The studs are black but after one or two on and offs, it seems they are in a way scrapping the blacking off the stud and the treads are bear metal and pretty bright. Nuts heat up when putting on and off do to friction and a fair amount of torque is needed to turn the nut off. It just does not seem right. Anyone run into this? Possible previous owner could have mixed SAE and metric? Not sure there is a SAE/Metric size this close. Any ideas?

[Stocker]

I have owned my '72 K20 for 45 years and rotate the tires myself. Still have the original lug nuts & original studs. They have always been tight as you describe, some worse than others but none of them spin freely like many other vehicles do. I break 'em loose by hand, then use a drill to spin them back on, then final tighten by hand. I used to do it all by hand with a 4-way lug wrench but that's just too much work.

Which is a long-winded way of saying that it's normal for them to be tight. At least you don't have to worry about them falling off!

[PbFut]

Good to know. Thank you for taking time to reply.

[Fbks_Cruiser]

My 72 GMC K2500 is like that too.

[HotWheelsFan]

1970 C-20... Same here, lug nuts can't be turned by hand. The threads are all good on mine.

[bry593]

Might sound crazy, but the cause of the issue is probably not the studs, but the conical seats in the steel rims. Years of torquing wear on the rim holes, causing the 60 degree to become more of a radius. This will eventually cause the tip of the lug nut to wear into a similar shape. The tip will eventually thin and squeeze down on the lug stud, thus causing a prevailing torque.

I ended up having to find a new set of rims. Took a long time to source a full set. I think I had 10 different rims and picked the best of the bunch. Installed with new (hardened) lug nuts and some studs. No problems since....

[PbFut]

Now that is a interesting point. I think I may have same issue. These lugs are way too tight. I work up a sweat taking 2 wheels off and on. I think I'll run over to Napa and pick up 8 lugs and see how they do. If they eventually tighten up, we know the issue.

[kwmech]

It is actually the both the nut and the conical part of the steel rim. After being torqued down a couple of times the taper of the nut actually starts to crimp down on the threads. Some high pressure grease or anti-seize will prevent possible galling of the threads. I only have this problem with steel rims. When I went to a larger tire and aluminum rims with different lug nuts the problem went away. AND I always use a torque wrench at 110 lbs for the 9/16 studs.

[Stocker]

I may be a bit off (just ask my wife, haha) but it has always seemed to me that when (or after) the OEM lug nuts were formed, they were slightly deformed by pinching them from side-to-side, thereby flattening them slightly -- just enough to make them harder to install & remove, therefore less likely to work loose when driving.

[kwmech]

That's exactly what I what talking about, it creates a full circle crimp when torqued down

[Steeveedee]

That reminds me. I just had new tires installed and I'm pretty sure they hammered the lug nuts on with an impact wrench. Time to bust 'em loose and apply the correct torque. I'll take a look at the wheels while I'm at it. Might have to buy new ones next time I get tires...about five years from now.