Why Do Tires Turn Brown?

Have you started to notice that your tires are no longer a nice dark black black color, but are slowly turning brown all over the sidewall?

In this article, we are going to explain why tires turn brown, whether browning is dangerous and what you can do to prevent it.

What causes tires to turn brown?

Tires turn brown due to a chemical known as antiozonant, which is naturally added to tires because it protects them from a variety of different external influences and increases their longevity.

It is a common misconception that silicone causes tires to turn brown. Silicone is sticky as it can gather a lot of dirt and dust on the sidewalls of your tires, which can make them turn brown. But, that’s actually not it. That brown “coating” can easily be removed with some water and a mop, and there are also chemicals you can use to remove the silicone, if it really bothers you that much. So, in case of silicone, your tires haven’t really turned brown – they’re just dirty.

In case they actually turned brown, you’ll know because you won’t be able to wipe it off with water and a mop.

The technical name of this process caused by Antiozonant is called “tire blooming”.

Antiozonant is actually an organic compound and is quite often used to prevent the degradation of certain materials caused by ozone (which is called ozone cracking) (1). It is mostly added to plastic and rubber and is a regular additive in tire manufacturing.

The antiozonant is added in such a way that the rubber material allows it to reach the surface and thus provide protection for the rubber and increase its longevity. But, as the antiozonant passes to the edge of the tire, it comes in touch with the oxygen and reacts, leaving a brown residue on the tire, which accumulates with time and makes the tires brown. This will eventually happen to all tires with antiozonant inside them.

How Mold Releases Contribute To The Issue

People usually think that the mold released during the tire manufacturing process makes the tires go brown, but, that is not true.

Mold releases are actually non-stick lubricants and are put in tire molds; their main function is to help release ready tires from the forms freely. Although they won’t make your tires brown, they can contribute to the process of tire blooming.

Namely, with mold releases being lubricants, they will keep more of the antiozonant near the surface of the tire, especially the outer edges; the outer edges are subjected to stronger oxidation.

The fact that some of the lubricants always remain on the tires doesn’t help.

Can You Remove Tire Blooming?

If there’s a small quantity of blooming on the tires, you might temporarily remove it with a thorough wash and a proper washing compound. This is never permanent, as the blooming will come back eventually, but you can postpone the whole process at least for a while before eventually deciding to replace your tires.

If the blooming has already spread around the tire, then – sadly – there’s not much you can do really. No amount of scrubbing or chemicals will remove that brown residue and the only things you can do is either move on and live with it, or replace your tires.

Blooming is an irreversible chemical reaction and every attempt of removing it would be useless.

Prevention And Protection

Although you cannot stop tire blooming or remove it once it’s already happened, there are ways you can postpone it for a while, but you have to maintain your tires regularly. In order to do so, you will have to regularly clean your tires and also protect them with additional chemicals.

The first thing you ought to do is wash them regularly. You should watch out and remove every piece of dirt that might possibly get stuck somewhere on the tire and you should do that without any water. After dry-cleaning your tire, you can apply a combination of soap and water and wash the tires. This will remove most of the dirt, but if you’re still unsure – you can repeat the action once or twice to be sure. After you’re done, just dry the tire with a towel and that’s it. We advise you to avoid aggressive chemicals when cleaning, as they might do more harm than good.

Then you need to apply a tire protection dressing. This will further protect your tires and make them more durable and will also remove any leftover blooming, if there isn’t much of it.

The simplest dressing is a water- or solvent-based compound, a liquid that fills the pores of the tires, thereby protecting them for a certain period.
You can also use tire wax, which is a bit more expensive, but can last for weeks and will both fill the pores of your tires and lubricate them.

Tire sealants are the least common types of dressings used, but they are becoming more and more popular, as they can last for up to a year if applied correctly. Tire sealants literally cover the tire with an additional protective layer, which allows it to look and stay fresh for a longer period of time when compared to the other two types.

If you regularly clean and protect your tires, you will prevent or postpone the effects of tire blooming, while simultaneously increasing the life of your tires.
Conclusion – is blooming a problem?

Final Words

Strictly speaking, tire blooming is not dangerous. Tire blooming is a relatively normal and natural procedure that doesn’t reflect on your tires in any way except aesthetically.

Blooming won’t damage your tire and it doesn’t mean your tire is “going bad” or rotting away. It’s just an unavoidable chemical reaction. What it does mean, though, is that your antiozonants are wearing out and that your tire loses its regular protection against oxidation.

This is also not a short-term issue, but it means that you’ll have to change your tires at some point.

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