Some really great info there folks....

 

Aluminum generally does not have a greater tensile strength than steel. Some high grades of aluminum do...but lug nuts and studs are made from something like 4140 or 1215 steel...and they're likely heat treated.

You also don't engineer or test for tensile strength. You do so for YIELD strength (the point where a material permanently deforms). You'd then add factor of safety to YIELD strength.

On fasteners, you don't even use yield strength for torque (and tension). You'd use ~75% of proof load, which is lower than yield strength. You'd still use yield strengths to derive shear and other values, though, IIRC.

The other issue is torque/tension relation, if we're being scientific. Friction between aluminum and steel materials would be different than steel/steel. So your torque value needs to be changed to provide the same tension in the fastener. Tension load is what torque value is derived from or vice versa. If friction goes up from softer aluminum threads gripping onto the steel surface, then torque must also rise.

A way to get a controllable value and consistently lower the friction would be to use anti-sieze. But...then, your torque would need to drop to a certain value. Idk what that is. Maybe 60 or 70 LB-FT. But...I wouldn't feel comfortable doing that.

Anti-seize would also prevent galling or corrosion issues with salt exposure. But I don't like using anti sieze on lug bolts.

All of these factors don't add up to much. You're likely getting inadequate clamping load at 80LB-FT of torque (DRY THREADS). But...with the engineered factor of safety, you'll likely never know...and your wheels probably will never fall off. Although, they may loosen and need checking more often. And most people wont use them in winter anyway.

I like using steel lug nuts for simplicity and reliability. I'd use closed ended steel lugs for year round cars. I'll take the 2oz. weight penalty.

 

I just bought a set of the McGard splines. Like said earlier, the finish is great and they warranty them for life. Even against finish wear. I have some Rays lugs as well. Those are much lighter being that they are aluminum, but I don't like the idea of them on there. Plus, the finish wheres off easily.

 

My 949 lugs should be here on Thursday. I'll snap some pics.

 

Was thinking of VMS stainless steel closed lugs look very nice quality any one used them ?
designed for corvette drag racing it seems, 2oz though but as said look very nice

 

As she sits

Attachment 175258

 

having used fancy Rays, not so fancy muteki, ebay no name aluminum ones and 949 racing. I vote for 949 racing. The price is right. You can buy 2 extra lug nuts with the order.

Good luck trying to find replacement neo chrome ebay or Rays ones if you accidentally lost one.

 

People lose lug nuts? Avoid working on your car next to the pit from the movie 300.