aluminum wheel PSA

[ramenth]

Hey, folks, just figured I'd post this up to take some of the mystery out of the aluminum wheel re-torque issue.

We've all seen it: take your car to a tire shop and walk out with a receipt that has a disclaimer on it saying that you should re-torque your aluminum wheels after so many miles or you've been talking to a buddy about how we has driving along one night to have one of his tires pass 'em because the the wheel came off.

I worked for a guy one time who worked on a lot of high end imports: BMW, Benz, Porsche, even once worked on a Ferrari and he was pretty anal retentive about following the TIA's (Tire Industry of America) recommended guidelines for proper wheel torque. Later on, when I went to work for a local tire/suspension/alignment shop I had to actually take these training courses, both for pass car and heavy duty trucks.

The other day I had an '04 Jag sitting in the shop, checking the tires over for leaks and doing a rotation when I decided to take some pics and offer up some of my knowledge and experience on aluminum wheels and the proper torque procedures to keep 'em on the car.

When aluminum is placed against steel the aluminum becomes a sacrificial metal. It will corrode faster than the steel. It's this corrosion that tends to make the wheel loose on the mating surface. That corrosion acts like a sponge, absorbing your torque values on the fasteners, and creating an uneven mating surface for the wheel against the rotor/drum.

Here's some pics of what I mean. Notice the corrosion on both the rotor and the wheel.

View attachment 7159

View attachment 7160

This corrosion needs to be cleaned off without damaging the aluminum. I like to use a 3M Roloc Clean and Strip wheel on a right angle die grinder. My former boss at the import shop and the tire shop I worked at both had a large electric grinder with a cupped wire wheel attached dedicated to the purpose. The cupped wire wheel allowed us to clean the wheel and still work around the lugs on the car to get the rotor/drum clean.

3M has this handy tool available to clean around the lugs:

View attachment 7164

It gets easier with drums. Pop 'em off and you don't have to work around the studs.

No matter how you do it, you still need to get everything clean.

Here's a comparison shot of the wheel as I started cleaning it.

View attachment 7161

And here's a shot of both the wheel and the mating surface clean

View attachment 7162

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Hand torque and you're done. (Although some manufacturers do recommend torque sticks.) You can check your torque again after a few miles if that makes you feel better. But you won't have to.

You've also seen guys -or are maybe one yourself - who uses anti-seize on the mating surfaces. That's not recommended as the ant-seize can do what the corrosion has done: acted as a sponge and absorbed the torque values and created an uneven surface for the wheel to mate. Remember, too, all torque values are a dry torque. If you've had luck with using anti-seize or grease, then I'm not going to say you're wrong, but just compare the practice to industry accepted guidelines.

Hopes this helps take some of the mystery out of the reason for the old "re-torque after so many miles" thing.

 

[Supershafts]

Ok there are some wrong issues here....

The mystery is not a mystery, it is simply heat and 2 dissimilar metals.

When you attach alum to steel you do get a corrosive action due to electrolysis, however this does not happen in minutes and days of use where the wheel winds up having the issue of loosening, what REALLY happens are the brakes heat, the rotors or drums are heat sinks, and the AL wheel is great at absorbing and dissipating HEAT, and AL also expands and contracts far more than Stl does.

The natural process between the AL and Stl is actually almost a weld between the 2, anyone who has removed AL wheels from cars that has this process taking place knows that you need to force to remove the 2....

The heat is the issue not the process of corrosion.

2 ways to combat such electrolysis issues are to coat both surfaces with either a inhibitor or a simple teflon insert made specifically for that reason.


The loosening issue is from the heat and the expansion and contraction of the AL, which is why you drive it, using the brakes as much as possible to get heat into it and then re-torque the wheels.



. Scary what some people are teaching

 

[ramenth]

Ok there are some wrong issues here....

The mystery is not a mystery, it is simply heat and 2 dissimilar metals.

When you attach alum to steel you do get a corrosive action due to electrolysis, however this does not happen in minutes and days of use where the wheel winds up having the issue of loosening, what REALLY happens are the brakes heat, the rotors or drums are heat sinks, and the AL wheel is great at absorbing and dissipating HEAT, and AL also expands and contracts far more than Stl does.

The natural process between the AL and Stl is actually almost a weld between the 2, anyone who has removed AL wheels from cars that has this process taking place knows that you need to force to remove the 2....

The heat is the issue not the process of corrosion.

2 ways to combat such electrolysis issues are to coat both surfaces with either a inhibitor or a simple teflon insert made specifically for that reason.


The loosening issue is from the heat and the expansion and contraction of the AL, which is why you drive it, using the brakes as much as possible to get heat into it and then re-torque the wheels.



. Scary what some people are teaching

As someone who also lives in New York, you're leaving out the naturally corrosive effects of salt and the reasons for the aluminum becoming a sacrificial metal in that case.

Sorry, but you're statements about brake heat are minimum at best. Don't know how you drive but I can go on a spirited braking drive with a customer's car on a test drive, come back to actually physically do the brake inspection and the rotors are cool to the touch. As are the wheels, as are the lugs. The thermal expansion is minimum at best. If the brakes were running hot all the time, say as with NASCAR on Bristol I'd agree with you, but with every day driving, and every day experience in a shop doing what I've just described, I'll disagree with you.

Nothing scary about spreading the word on what's industry related guidelines.

 

[Supershafts]

I work with AL and it's corrosion issues directly associated with all kinds of issues all day everyday in the most hostile environments without failure because i know exactly what issues are related.


You come for a quick spirited drive with me and i'll watch you lose the ability to have finger prints for a few weeks at least just by touching any part of the front wheel guaranteed, the rear will be warm enough you aren't leaving your hand there for any length of time...

Im telling you about this as you are misinformed by so called experts that aren't always that, but i have met many a wrong theories from many a supposed expert in the field that were wrong for 10, 20 even 30 years or more. . .
Even the electrolysis taking place is due to heat more so than any other reason like road salt as they probably instructed you to believe. .

This is why in our industry some of us that really know seal the area's of interest within AL to Stl parts.

You can disagree but as you learn you'll see i am right, the one thing i have learned in this world is usually the person to make the 1st statement is always looked at as if they are right.

The thing is i can prove im right in one little test. . .

How many people on this board will admit to having such a issue of losing a wheel, and tell everyone of the timeline in which this accident happened from installing said wheel and how much use the vehicle in question had.

This was a huge issue with the uni pattern wheels and many people misinformed had wheels loosening up in hours... hours electrolysis isn't even a thought.

electrolysis on a car or truck takes months, maybe more than a year, in the marine world it takes months unless the 2 are directly in contact with the water and there are no sacrificial zincs.

Aluminum doesn't corrode like stl in salt or humid conditions, it actually forms its own protective barrier, the only place AL will have a issue of corrosive action is UNTREATED areas between two dissimilar contacts.
It's why i love AL shafts in jeeps & trucks running the beach rather than stl. . .also why the shafts don't rot away when being parked in dirt and the rest of the car does. .

Usually you'll lose a wheel in hours or a few days.... the expansion and contraction of the AL from the heat and cooling is the cause....

 

[moparleo]

We threw away the torque sticks at my former emplyer, Bridgestone/Firestone. As you may or may not know torque sticks require a dedicated air source, its own regulated airline and impact gun and the user must hold the impact gun with the same of grip pressure for the sticks to give a consistent reading. You are both correct in what happens to aluminum as to corossion and heat cycles. Most wheel offs occur with a new wheel not old wheels. When the lug nuts are torqued ( the studs stretch because they are slightly elastic ) and the aluminum compresses slightly, this is what keeps the wheel tight to the hubs. That is why the wheel manufacturers all recommend rechecking the torque after 500 miles. The recommendation to recheck wheel torque is only with alloy wheel centers. On a steel rim if you inspect where the lugnut seats, the rim seat is slightly raised with a space between the lug face and hub. The lug seat compresses like a coil spring when tightened and maintains the torque because the rims and lugs grow and retract at the same rates. Torque is nothing but a measured amount of stretch in the fastener. To be consistent, you should always make sure that the hub area that the wheel comes in contact with is cleaned of all forein matter, be it rust,dirt, aluminum corrosion or whatever and wheel studs and lug nuts have a clean thread surface. Torque readings are with a clean, lightly oiled fastener, just like engine fastener torque recommendations.
But the rule of thumb is that it doesn't hurt to recheck the lug nuts shortly after putting the wheels back on. aluminum turns to a white powder when it oxidizes.

35 years in the tire and repair industry.

 

[BlakeLSU4ME]

 

[BlakeLSU4ME]

galvanic cycle, for two dissimilar metals in contact. there does have to be a medium establishing an electron field for the corrosion to take place though. Water, road salt, mud, etc etc.