Alloys or steel rims

[Wolf427]

Steel all the way. I wanted alloys for the longest time because I thought they were lighter, but as it turns out all the alloy wheels I like are very similar in weight to the steelies I'm running(+/-3-5lbs) .

 

[Lindenwood]

I'll jump in on that because up until a few weeks ago, I thought the same thing. However, I've since learned (as I'm building a bunch of stuff out of aluminum) that Aluminum corrosion is kind of unique. When folks see aluminum corroding, most of the time they are witnessing Galvanic Corrosion. Aluminum on it's own will not corrode. It will form an oxide layer but that then seals it from further oxidation. Steel on the other hand oxidizes a bit differently and doesn't 'self seal' against further oxidation the way aluminum does. However, aluminum + steel & electrolyte WILL corrode; rapidly and substantially. This is galvanic corrosion. Basically the aluminum and the steel become like the different bits of a battery, and the aluminum sacrifices electrons to the steel via the electrolyte.

One of the best electrolytes on the planet is salt water, so salted roads in winter + aluminum wheels + steel hubs = corrosion.

Still, modern alloys are FAR better than steels for reasons other posters have mentioned. We always make sure to use anti-seizing grease wherever aluminum and steel will mate up to prevent them from corroding and seizing together.

Great info! However, this wouldn't explain the aforementioned lip and bead issues, no?

 

[ChasingOurTrunks]

Great info! However, this wouldn't explain the aforementioned lip and bead issues, no?

Great question and I honestly don’t know. I have very limited tire experience so I’m not familiar with that corrosion. I never saw it on the two sets of wheels I went through on my JK but they didn’t use a ton of salt in Alberta for most of those miles.

There’s also an even chance that I didn’t explain the galvanic thing properly so my post will be edited accordingly in a moment!

 

[9Mike2]

Still, modern alloys are FAR better than steels for reasons other posters have mentioned. We always make sure to use anti-seizing grease wherever aluminum and steel will mate up to prevent them from corroding and seizing together.

Very good point!!

 

[MazeVX]

Great info! However, this wouldn't explain the aforementioned lip and bead issues, no?

Actually it does, the salt does its job anyway, no other thing needed and here's the point where the quality kicks in.
When you have a cast aluminum rim the lip is far outside of the cast and has a big chance that mistakes in the uniformity of the material are close to the outside also can there be problems with the uniformity of the alloy itself due to the casting process. When the corrosion reaches such a mistake it can make its way all through the rim and that's not unlikely to happen, you just don't see it.
And it can only be prevented through good quality.

 

[Lindenwood]

Actually it does, the salt does its job anyway, no other thing needed and here's the point where the quality kicks in.
When you have a cast aluminum rim the lip is far outside of the cast and has a big chance that mistakes in the uniformity of the material are close to the outside also can there be problems with the uniformity of the alloy itself due to the casting process. When the corrosion reaches such a mistake it can make its way all through the rim and that's not unlikely to happen, you just don't see it.
And it can only be prevented through good quality.

Fair, but that's not galvanic corrision.

Ultimately, doing some digging on my own, it sounds like friction between the tire and rim either wears through thin coatings or, with other intrusions (samd and salt), forms small abrasions in the aluminum. In these areas, corrosion forms, making the mounting surface even more uneven, which has caused leaks at the bead. Of note, it sounds like the corrosion plays a bigger role in making the bead uneven than the scratches alone, as leaking beads are not really associated with non-wintery environments.

It does sound tougher alloys, metallurgical improvements (like forging), and/or better coatings make aluminum rins more resistant to this; in fact, all of the articles and posts I read referenced cast (cheap) OEM wheels.

It still surprises me that steel wheels would be less succeptible to this corrosion-induced bead leaking. One hypothesis would be that steel wheels likely receive sturdier coatings given their obvious proclivity for rusting, whereas aluminum wheels seem more likely to receive only a thin clearcoat, or even no coating at all. If that is the case, it sounds like the problem is not with the wheel material, but with the coating, which are not inherently connected.

 

[MazeVX]

I never heard of leaking beads, honestly...
Every tire will leak when you push it hard because of the massive movement of the sidewall, that's common to racecars and for sure common for the offroad world.
It's important to have someone who really takes care of and know what he's doing when mounting tires to rims for people with high requirements like us.
I didn't talk about the galvanic corrosion... Never had a problem problem with that even with copper paste on the hub... Nothing has happened, but there's a special hub paste available if you want something try this.
We had a rim with massive corrosion damage on the hub flange but it was like 25 years old... You can't really complain about it.

 

[Anak]

We had a rim with massive corrosion damage on the hub flange but it was like 25 years old... You can't really complain about it.

I can't?

I have a '55 Cadillac with steel wheels that are just fine. No funny corrosion problems. I just have to remember that the left side of the car has left handed lug nuts. But that is another issue.

Most of my vehicles are from the mid '90s. I would hate to suddenly find that I need to replace all their wheels. I would be bound to complain to somebody. I know it wouldn't do any good, but I would still complain. I am just that kind of pain.

I do expect that road salt is the issue, and without knowing exactly what is happening I expect there is a chemical reaction in which aluminum oxide forms more readily than does iron oxide.

Also note that some factory alloys are good quality. The Hungarian GM 2500HD alloys from the 2000s are a forged alloy. I expect there are others.

 

[Lindenwood]

Of course, that depends 101% on location. A car borne and raised in Arizona likely won't have a spot of rust after 50 years, while probably half the NE US vehicles on the road are probably unsafe after 20.

 

[MazeVX]

I can't?

I have a '55 Cadillac with steel wheels that are just fine. No funny corrosion problems. I just have to remember that the left side of the car has left handed lug nuts. But that is another issue.

Most of my vehicles are from the mid '90s. I would hate to suddenly find that I need to replace all their wheels. I would be bound to complain to somebody. I know it wouldn't do any good, but I would still complain. I am just that kind of pain.

I do expect that road salt is the issue, and without knowing exactly what is happening I expect there is a chemical reaction in which aluminum oxide forms more readily than does iron oxide.

Also note that some factory alloys are good quality. The Hungarian GM 2500HD alloys from the 2000s are a forged alloy. I expect there are others.

I get your point, but, as I said, it was one... so there where many others without problems.
And it's definitely dependent on the location / country. With a 25 years old car here, the last thing you would worry about are the rims.

 

[Dilldog]

I'll jump in on that because up until a few weeks ago, I thought the same thing. However, I've since learned (as I'm building a bunch of stuff out of aluminum) that Aluminum corrosion is kind of unique. When folks see aluminum corroding, most of the time they are witnessing Galvanic Corrosion. Aluminum on it's own will not corrode. It will form an oxide layer but that then seals it from further oxidation. Steel on the other hand oxidizes a bit differently and doesn't 'self seal' against further oxidation the way aluminum does. However, aluminum + steel & electrolyte WILL corrode; rapidly and substantially. This is galvanic corrosion. Basically the aluminum and the steel become like the different bits of a battery, and the aluminum sacrifices electrons to the steel via the electrolyte.

One of the best electrolytes on the planet is salt water, so salted roads in winter + aluminum wheels + steel hubs = corrosion.

Still, modern alloys are FAR better than steels for reasons other posters have mentioned. We always make sure to use anti-seizing grease wherever aluminum and steel will mate up to prevent them from corroding and seizing together.

Edit to add: I’m only 50% sure I got the explanation of galvanic corrosion correct, so don’t go citing this forum post in any research papers ;)

Your explanation of galvanic corrosion does a good job of getting the point across while not going into the chemistry too deeply (I learned all about this as a journeyman air frame technician). Galvanic corrosion has to do with atomic charge, and as such there is a lot of chemistry involved in predicting witch metal will corrode in a pair and at what rate, and also what the best blocker of said corrosion is. As such most of the time petroleum based products are not always the best as they will carry an electrical current, the best things are silicone based sealants and lubricants as silicone is an electrical insulator.

 

[Buzzard13]

Beadlocks are not for daily drivers, correct?
I vote Steel. I run an old 78 Dodge, 8 lug, and sure I'm not going to beat it, though I am not sure Aluminum would look right. Functionality I think it all would work the same.
Now for my trail truck I plan on running 17in 8 lug steels because they are heavy duty and I won't be shy of beating this truck.

 

[OtherOrb]

Similar conversation here: alloy vs steel

And I'll repeat my (rewritten) comment from that thread:

The most important reason to choose alloy over steel is that for the same diameter, width, and strength, alloy/aluminum wheels have significantly less unsprung, spinning weight. Less unsprung, spinning weight means far less wear and tear on almost all parts of the vehicle. I know 25 to 40 pounds of weight savings doesn't sound like much, but it's rather huge over the life of the vehicle when you're talking unsprung and spinning weight. This kind of weight has an impact on everything from the suspension to the axles to the bearings to the brakes to the road feel. It's much more important than a few pounds added to the cab of the truck.

In my decades of overlanding, I have never seen a wheel damaged in the way most demonstrations show (sledgehammer). Mostly it was a small knick or dent to the rim. And usually it did not impact the bead and therefore wasn't important enough to be a problem. The very few times it was a problem, the wheel was replaced with the spare and we kept going. Once we were home, the damage was assessed by an expert and either the wheel damage was ignored, repaired, or the wheel was replaced. But we had spares in the field so it really wasn't an issue that required field repairs in the manner suggested by the video.

I certainly would never take my loved ones to ride a pressurized tire on a wheel that had been hammered back into shape on the side of the road by a non-expert. The stresses involved and the microfractures caused by that hammering are too dangerous to take up to pressure or up to speed.

Keep your wheels spinning.
Throw the spare on and stay safe.