What is tire blooming

Tire sidewalls turn brown mainly because of an element added to the rubber called antiozonant. It saves tires from premature drying and cracking due to the process of oxidation. Tire browning is usually called blooming. Its a continuing process that can be prevented by thoroughly cleaning and protecting the tires.

Mold releases may contribute to the problem, but they arent the cause of tire blooming. Silicone is also not the cause of tire browning.

Why Antiozonant Causes Tire Sidewalls to Turn Brown

Tires bloom because antiozonant pushes its way to the outer edge of the rubber casing with time. As the element comes into contact with oxygen, it leaves a brown residue on the surface of the tire. Antiozonant is organic and helps tires last longer as it slows deterioration due to oxidation. This is what makes it possible to manufacture long-lasting high-mileage tires that can last up to 10 years.

The rubber structure is built in a way that allows the element to move forward to the surface, thus continuingly providing the material with its benefits. As a result, the tire remains pliable and UV/oxygen-resistant for a longer time.

Reference

https://www.utires.com/articles/tire-sidewalls-turn-brown-prevent/