Is there something wrong with Porsche aluminum lug nuts that they are not safe for the track? So I should buy steel ones because they'er safer? I've heard some P-clubs make you use steel?

My other track cars have all used forged aluminum lug nuts and have been fine. I always checked them between runs and never had to tighten them once they've been torqued properly.

Besides, I haven't seen steel ones in different colors! j/k

tom

 

I think one of the problems is the lug nuts can shear apart if you try to remove them when they are really hot.

 

my only experience with them is that some of them on my 944 were corroded and flaking apart. i replaced all 20 lug nuts without hesitation and bought new aluminum lug nuts. a couple of the oem lug nuts flaked apart and corroded so much that they looked as though they were magnesuim. i don't think there's anything wrong with the aluminum lug nuts other than the corrosion factor, chance of oxidation due to dissimilar metals of the studs and lug nuts (i grease mine with a light coat of wheel bearing grease to avoid that), and the chance of stripping when over torquing. i think the spec is something like 94 ft/lbs but i'd double check the manual.

 

I've always swapped to steel for track days when I install the track wheels/tires because I figured that saved a few on/off/torque wear cycles on my cosmetically nice aluminum nuts. PCA never made me do it for AX/TT/DE events, I just did it on my own to prevent scratch on those expensive aluminum nuts.

 

I run steel on my 944 spec and for me the biggest issue is that those lug nuts go on an off the car something like 2 times a day. I don't know how long the aluminum would last before being damaged.

On a street car you put them on and what 5k or 10k miles later you rotate tires? So what they cycle once or twice a year maybe? Far different from my once or twice a day track car stuff.

 

PCA Racing rulebook is clear "Lugnuts must be steel with engagement at least equal to the diameter of the wheel lug studs". Would aluminum be OK for DE? I am not aware of that being checked for at DE's
Cheers
Randy

 

I run steel on my car but I also club race. I usually tech cars at the local PCA DE's and don't fail anyone with aluminum lug nuts. However, I do suggest that if they are going to be doing DE's frequently, they think about switching to steel. PCA racing usually doesn't implement rules lightly. They have probably seen failures. The stress on the lugs in a DE isn't a whole lot different than Club Racing.

 

Aluminum and steel react differently to heat. Use the steel since the studs are also steel.

Aluminum tends to heat up quicker and, because it is softer, will stretch and not hold the tq as well as the steel/steel arangement.

 

Thanks again guys. Your responses make sense.

Better safe than losing a wheel on the track!

Do you put anything on the threads so the lugnuts come off easier? (although I'm not sure this is a good idea? I was taught not to put anything on the threads for aluminum lugnuts but I've never used steel ones before)

tom

 

I've always used anti-seize on my steel lug nuts.

 

Use anti-seize on steel, and I would say it is even more important to use anti-seize on alum/alloy nuts than steel, as it is easy for the alum to gall and the dissimilar metals corrode, especially in a wheel nut application on a daily driver. Check the history here of where guys have had a wheel nut seize and tried to figure out a way of getting it off w/o destroying the wheel.

I have never seen or heard of a porsche alloy nut failing, other than breaking a seized one when trying to remove. Never a wheel falling off from 5 failed nuts (that were properly torqued) - thats unheard of. Wheel centers will fail before the nuts and studs do.

But yes, PCA and most all racing organizations do require steel nuts for Club Racing (not DE's). No harm in using steel. Primarily they will not get as chewed up w/ frequent wheel changes and re-torques. Also, with the open ended steel nuts, the scrutineers can see full thread engagement. W/ the closed ended alloy nuts, no idea how far the threads are engaged, if using spacers or offbrand wheels that have a thicker face/center.

The point about different thermal expansion between alum and steel is a good one. Possible that high heat (from the brakes) could loosen alloy nuts on steel studs after multiple cycles. Although, I dont recall noticing much evidence of that happening on 951s that I DE'd for 6-7 yrs before going to steel nuts.

 

I think the point of using the steel lug nuts is: aluminum is softer, and therefore more likely to be damaged if cross threaded... a cross threaded aluminum lug nut is more likely to fail than a steel one.

 

And tracked cars tend to remove and install the wheels alot so you have more risk. With steel you don't need to be as careful.

 

I wish I had steel nuts.

 

I also think heat is an important factor. Having just swapped tires right off a 25 minute session, my steel lug nuts will cause serious burns if you don't have gloves on.