Lugnut Torque Spec

Why is the lugnut torque spec different if you have steel wheels vs. aluminum wheels?

 

I may be wrong but I have heard that it is because aluminum is softer than steel and can deform under higher torque

 

This makes sense to me.

I also wonder if we should be using a different spec with aftermarket wheels and lugs.

 

Very interesting. Is that from the 4Runner owner's manual?

 

Honestly, I never thought about that. Also makes sense since there are cast, forged, billet etc... aluminum wheels that all have different strength. However, it doesn't seem that the range between aluminum and steel is that different so I'm sure 76lbs is good for all aluminum wheels.

 

Yes starting in 2015. 2014 and prior manuals didn't have the lower torque for aluminum wheels.

I checked the GX manuals and it's the same. Lugnut torque went from 83 ft-lb in 2014 to 76 ft-lb in 2015.

Are 2015+ 4Runner and GX460 wheels weaker?

 

Just remember it is recommended to re torque after 50 miles. I have always done this on aluminum when possible.

 

I've always done all vehicles at 85ish.

 

What I found interesting was the reference in my SR5 owner's manual stating as above, 83 for steel, 76 for aluminum but the documentation in the boxes my TRD Pro wheels came in from the local dealership said 82 and they are of course aluminum.

 

In the shop I worked in as a teenager pretty much all the mechanics just used the German torque spec--gutentight.

In all seriousness, though, the point is thousands of mechanics just give each lug nut a 1-2 second burst from an impact gun and never mess with the torque wrench. A few ft-lbs one way or another probably won't make any noticeable difference in anything we can detect.

That said, I do use a torque wrench on lug nuts these days because I like to be meticulous.