This is a discussion on Aluminum vs Steel lug nuts within the Suspension & Wheels forums, part of the Tech & Modifying & General Repairs category; I was looking for a set of lug nuts & came across these aluminum ones made by Blox racing. Is ...
Aluminum (and titanium) lug nuts were originally a racing derived application to keep weight off of the car, especially un-sprung rotating weight. Since the life cycle of a racing lug nut is very low (often 1 race or 1 pit stop) any kind of galvanic corrosion, fatigue, thread stripping is deemed negligible in that application. For the street however, I've never really seen the point in running them as there are a lot of things to watch out for (risks).
* Be wary of imitators and knock off lug nuts from China. There is a long history of shiesty materials practices.
* I would not run cheap non-reputable alloy lug nuts on my car, not worth my life to save 4oz a wheel.
To answer your question directly, yes you can get corrosion between the steel and aluminum especially if you use these lug nuts in a salty environment like the ocean/coast or the snow. Aluminum while it does not rust, does corrode in these circumstances. (I see it every day in our fleet)
Other issues to watch for:
---Galling/stripping of threads. If you use an alloy lug nut be wary and adhere to torquing sequences and torque specs. Over torquing here can be your demise.
---Cross threading an alloy lug nut is very easy
---Inspect the lug nuts after each removal/ try to minimize removal
---Keep spares on hand
FWIW these lug nuts achieve "full strength" through thread engagement length. If you have a bolt and nut of the exact same material type and hardness (i.e. grade 5 nut and bolt), achieving full strength requires very few threads.
With dissimilar materials and 1 being softer or less hard than the other, achieving full strength requires a lot longer thread engagement or more threads. That is why the aluminum or titanium lug nuts have open ends and are a lot longer than the factory "acorn nuts". The equation for calculating this "engagement area" is in the Machinery's Handbook, and isn't too tough to follow.
I recently had to calculate thread engagement area for full strength of 2 dissimilar steels....I enjoyed life much more when I was ignorant.
Thanks for the comprehensive reply.
The metal incompatibility issue was my main concern.And corrosion of course since I wanted to get these for my winter wheels.
I hadn't considered Al lug nuts until I was offered them at a good price.I'll forget about them & just get steel lug nuts instead.
I have been running aluminum lug nuts in winter and have had no problems at all.
Also as stated in my OP, if you have reputable name brand lug nuts like Sparco, Volk, Rays, etc., you may never encounter a problem as they have probably accounted for these issues and designed accordingly. But these lug nuts are also spendy at often $80-$180 for the set.
Just know that aluminum lug nuts are a higher maintenance item than steel ones.
A saying here at work that always seems to ring true in instances such as this is: "It always works until it doesn't."
I live in Minnesota, so they see lots of snow and salt. I usually check torque about once a month and have never had one loose. I also put a Dab of anti seize on them to make sure I never have one get froze to the stud.
Ya, I've never had one bit of a problem. Crap, I've tightened lugs with a 3/4 ratchet and have never had them come loose before Lol
I bought some Rays racing lug nut and I never had any problem with them. I also used a little anti seize on them and I always tightened them to 90-95 lbft they call for 85 lbft. I even forgot to tell one tire shop not to use there impact wrench and after they brought me the car back I checked the torque and it was at around 135 lbft and they didn't strip the threads they have really impressed me.
If the price isn't excellent I'd not bother. Even with a great price, I'd only bother if I needed lug nuts... A while back, there were ultra-fancy lug nuts for turbo AWD Fords made of... beryllium. I won't bore you with the pricing but it was a number with several digits more than I'd expected. As mentioned the fancy lugs when used in anger are expected to last an event or two, not a road car's lifetime.
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It is only steel for my cars. Securely fastened wheels are far more important than a little less weight.
I got a set of McGard lugs that claim to never rust. So far, so good.
I just bought a set of Muteki lug nuts eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices
I'm a little more careful about my wheels after one of them came loose last year.It could have ended bad as I had just exited the freeway & a good Samaritan behind me was honking wildly at me & came up to to say that one of my wheels was wobbling.
Turns out that wheel was missing a hubcentric ring.I had not noticed this while installing.Not entirely my fault as tirerack didn't send them with the wheels.
Last edited by rage-wrx; 11-23-2011 at 04:41 PM.