Do Aluminum Alloy Wheels Rust?


You probably have some sort of aluminum alloy wheels on your car, truck or SUV unless it’s pretty old or it was an entry-level model when it was bought new, but can your alloy wheels rust over time and will they need replacing or replacing at some point?

Alloy wheels do not rust, but they can suffer from something called corrosion if the protective coating applied to them to prevent corrosion becomes scratched or damaged. Unlike the familiar brownish hue we see with rust on steel wheels, the corrosion allows wheels can suffer from appears as a white bubbling on the surface that some may mistake for rust.

What is alloy wheel corrosion?

Corrosion of alloy wheels is actually a process called oxidation, which is where a chemical reaction occurs between air and water that causes the alloy wheel to pit and bubble. If the protective factory clear coating applied to the wheels when they’re first manufactured is compromised in some way, this allows oxidation to start. The main ways this protective coating is compromised is through damage caused by hitting the curb and from the outer wheel weights used for balancing the wheel, but other things can cause alloy wheels to corrode too.

Why is alloy wheel corrosion a problem?

There are two main problems corrosion cause with alloy wheels. The first and most obvious problem is that corroded alloy wheels look unsightly. Even if this doesn’t particularly bother you, it certainly will do when you eventually come to sell your car and prospective buyers beat you down on price because of the poor condition of your wheels. It’s not just the wheels looking bad that will hurt your resale price either. If a prospective buyer sees you haven’t bothered to take care of your wheels they could start to wonder what other areas of neglect there may be that they’ll need to be concerned about with the vehicle you’re selling.

Another problem with alloy wheel corrosion is it can compromise the integrity of the seal between your tire and your rim. Even a relatively small amount of bubbling corrosion on your alloy wheel where it seals with the rubber can lift the rubber away from the alloy wheel and allow air to escape.

The first time I came across this problem myself it was a real eye-opener for me. I had a used car that was about 10 years old in great condition with a set of tires on it that looked almost new. Even so, I appeared to have slow punctures in three of the four tires and I, therefore, drove to a tire center to have the punctures fixed. When they tested the tires they found no punctures whatsoever. They concluded that the alloy wheels were the problem instead, and to fix them I had to have them remove the tires and send the wheels away for shot-blasting and a protective coating re-applied.

Causes of alloy wheel corrosion

Physical damage

The most common way for alloy wheel coatings to be compromised and for corrosion to get a foothold is physical damage, and the most common way alloy wheels get damaged is by them being “curbed.” It’s really easy for even experienced drivers to scratch or dent an alloy wheel by catching the curb when parking or turning a corner where there’s a high curb. How susceptible your alloy wheels are to such damage will largely depend on how high the curb is and the design and size of your alloy wheels.

Brake dust

If you’re someone who likes to keep their car clean as much as possible you’re probably very familiar with brake dust. Brake dust is an unavoidable result of conventional brake shoes doing their job by applying considerable friction to the rotors when you press the brake pedal to slow or stop your vehicle. This friction inevitably wears away the brake shoe material and some of the fine dust the process of braking creates sticks to your alloy wheels.

You probably thought the main problem with brake dust is it spoils the look of your alloys (unless they’re black of course), but it can also be a big problem for the condition of your alloy wheels too. Brake dust can actually burn tiny marks into the surface of alloy wheels if not removed regularly, and over time, the combination of brake dust, moisture and dirt can lead to severe corrosion and pitting of alloy wheels.

It’s not too difficult to remove brake dust from your alloys yourself weekly using appropriate cleaning products like the ones I recommend here from Torque Detail for other parts of your vehicle. I’ve been sending people to this supplier for a while now and hearing nothing back other than good reports. Regardless of where you buy your detailing products from, however, it’s important to make sure you use the right product for the job and that you follow the instructions for use. If you don’t remove brake dust from your alloys regularly you’ll eventually get to the point where cleaning alone won’t make your alloys look like new again and you’ll have to resort to a professional alloy wheel repairer.

Low acid spray corrosion

A lot of the cleaning solutions used by professional detailers contain low levels of ammonia or acid, and you can also buy these products from auto shops to use yourself. Acid is a great substance for removing brake dust from the surface of alloy wheels and the longer you leave it on, the easier it is to wash away the brake dust and other grime from your wheels. The problems begin when you’re tempted to leave the acid on the wheel too long. If left too long it will burn away the protective coating and corrosion and oxidation can start to take hold within weeks.

Abrasion

As well as being careful about the chemicals you use to clean your alloy wheels, you also have to be careful about what you use to “agitate” the cleaning solution. If you haven’t cleaned your wheels for a long time and a thick layer of brake dust has accumulated on your alloys, it may need a brush or pad of some sort to work in conjunction with the cleaning product to do a proper job of cleaning the wheel.

Wire brushes and scouring pads will do a great job of removing the brake dust and dirt from your wheels but they can also do a fantastic job of scratching away the protective coating that will then allow air and moisture to get to the alloy and start the process of oxidation. If you have to use something to help the cleaning solution do its job, try to use a soft brush or cloth instead of something that will remove far more than just the stuff you want to remove.

Removing corrosion from alloy wheels

If you’ve ever had a professional refurbish done for you on a set of alloy wheels you could easily assume it’s some sort of “black art” that requires a ton of expensive special equipment and a lifetime of experience to do properly. In some of the worst cases, it is and it does, but some of the time you can do a decent job of removing the corrosion from the visible surfaces of your alloys.

There are many rust or corrosion removers on the market that are safe to be used on alloy wheels, but always read the instructions carefully and use as recommended. Stick to the exact way these products are supposed to be used and then follow these next instructions.

  • Scrub any areas of corrosion with something suitable for the job such as a nylon scrubber, and this will often be enough to remove the white spots of rust that have begun to appear on your car’s wheels. It’s not brown rust you’re looking for here on your alloy wheels, but a white bubbling material that makes it obvious a type of corrosion is present.
  • Use a steel wool scrubber if you absolutely must to clean the rest of the particularly badly rusted areas, and continue until the affected areas are smooth and the rust spots have gone.
  • Be sure to get to all the spots around lug nuts, holes in the middle of the wheel, and any hard-to-get-to areas, but don’t get too enthusiastic and rub too hard with the steel wool as the aluminum alloy is a softer metal than steel and many other metals.
  • Once you’ve removed the corrosion, rinse the wheels thoroughly to remove any remaining particles of corrosion that have been scrubbed away. Don’t worry about the water you’re using rusting the wheel all over again because it won’t.
  • It’s also a good idea to use soap and sponges with clean warm water to wash the wheels properly and do a final check for any areas of corrosion you might have missed. If you do spot further areas of corrosion damage, use a suitable wheel cleaner to remove it.
  • Once you’ve done all this and you’re happy with the result, always make sure the wheels are properly dry before moving on to the final step. It can be easy to get carried away and want to move on to the really good bit of adding the final touches too soon, but the last stop won’t be as effective as it should be if the wheel isn’t properly dry first.
  • The final step is to use a specialist wheel polish or wax to get the alloy shining right up and to apply a degree of protection to the surface to prevent further corrosion.

Is it time to call in the professionals?

There’s a big difference between alloy wheels with a bit of corrosion and oxidation setting in on the surface and badly damaged wheels that have been scraped, scratched and gouged for an extended period. You could do a minor refurbishment yourself using the method stated above and the appropriate products, but serious damage should be referred to an expert.

You really would be amazed at what an incredible job a good wheel refinisher can do with alloy wheels in a condition so bad you might think replacement was the only option.

A dealership I worked in once had a demo SUV that was being driven by the boss’s very young wife who had only been driving for a very short while. Every couple of weeks the service department was calling in the wheel refinisher to fix scratches and chunks missing from the wheels she’d caused by hitting the curb all the time.

About four months later, after the demo had been replaced and sold to a retail customer, the SUV kept coming back into the service department for handling issues. It turned out the alloy wheels had so much filler in them from constant repairs that proper alignment and balancing wasn’t possible with them on the vehicle. The only solution was for them to be replaced at a cost to the dealership of several thousand dollars, even though they looked as though they were absolutely brand new.

This was, of course, an extreme example. But it did show me just how well an alloy wheel can be cosmetically repaired to look like new. The alloys on this particular SUV were fitted with very low-profile tires, and to be fair to the young and inexperienced driver, the design of the alloys did mean they stuck out a little from the tire rather than being protected by it.

If you have something like a Jeep Wrangler or Land Rover Defender with big, chunky tires and relatively small alloy wheels you may never have to worry about hitting a curb damaging your wheels as the tires will take care of things for you. On the other hand, if you go for a set of big, shiny alloys with ultra-low profile tires for the bling, you might want to get the number of a good wheel refinisher unless you’re going to be super-careful when parking.

Sean Cooper

Former retail auto industry professional for almost a decade and now an automotive writer and journalist for the last 7 years

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