Have you ever seen these new tyres before?
The sidewall has brownish dust-like covering the circumferences of the tyre. I have got a few who asked me if they got scam by me. One is skeptical about the explaination. These people are concerned if the tyres are second hand / used tyres.
Tyre blooming
Blooming is the chemical process result in brown residue on the sidewall due to oxidation of the anti-aging chemicals in the tyre. Therefore, the brown look of the tyre is not an indication of second hand tyre / used tyre. It’s just the ant-aging chemical working to protect the tyre from aging.
If you search everywhere about this, none of the tyre manufacturers mention about this in their websites. So, how to prove that the residue is really the result of tyre blooming? We need to find out the materials added to the tyre.
Materials in the tyre
According to Continental official website, anti-ageing agents are added in the tyre. Same as Bridgestone official website, antioxidant is added to inhibit oxidation of rubber. Anti-Ageing and antioxidants are the same thing.
This chemical prevents crack and early tyre aging after the tyre has manufactured.
What’s inside the anti-oxidant
Inside, there is a common chemical known as 6PPD , chemical formula : C18H24N2 (p-phenylenediamine derivative). This is further proven by Tyres Europe and United States Environmental Protection Agency that 6PPD is indeed inside all the tyres manufactured in the world.
6PPD Chemical Reaction Becomes Brown Color
This chemical reacts with ozone (O3) in the air results in 6PPD-quinone. 6PPD-quinone on the tyre looks brown in color (click to see the color of 6PPD-q mentioned in the article). Dark orange looks like brown. In a very rare case, a little red color can also be seen on the tyre. Just that none of the customers have ever seen this before.
Even after brand new tyre has installed and start running, as long as 6PPD still remained inside the tyre, brownish residue will still appear on the tyre sidewall. That’s why some drivers wanted to use tyre wax to make tyre looks clean and shine, resulting in faster tyre aging.
Because a used tyre and a new tyre both have brown residue on the sidewall, some may think the new acquired tyre is a used tyre.
What about the white color residue?
Interestingly, a customer recently raises a concern if this white residue is a defect and/or second hand tyre.
There is no official statement from tyre manufacturers related to the white /greyish color residue. But it can be referred from Michelin bicycle tyre that the white color residue is a form of wax used to protect the tyre. Just like the anti-aging chemical.
Hywax product brochure and a organization report prepared for U.S. Tire Manufacturers Association, paraffin wax, which is white in color, is used in tyre production.
“Blends of microcrystalline and paraffin waxes are currently used as processing aids in production of tire rubber to provide lubrication, mold release, and improve ozone resistance. While cars are in motion, the wax film breaks.”
To further prove that the white color residue isn’t a product of second hand tyre, look around the tyres installed on other vehicles and your previous set of tyres. Do they have any white /greyish residue on the sidewall?
None. As such, some people often used that as an indication of to distinguish new tyre from second hand tyre.
Environmental pollution caused by 6PPD
Since we are getting into tyre product chemicals, I may as well mention about 6PPD side effect.
When 6PPD turns into 6PPD-quinone (6PPD-Q), this chemical becomes toxic to our environment. When tyre wears off, the particles, together with 6PPD-Q, goes into the road and washed off to the sea. Besides, it can airborne, and it’s found inside human in the year 2022.
A report released in year 2025 from an organization that Yokohama, as a major manufacturer using less 6PPD, and so is Kumho.
Conclusion
Rest assured, the white / brown film isn’t a defect or used tyre. Sometimes dirt just get onto the tyre when technician roll the new tyres on the ground to the shelf.
Afterall, it’s not easy to find second hand tyres that look like brand new that still with label sticker on it. There are so many combination of tyre sizes. Take a look at Pirelli Cinturato P7 tyre list for instance. Even for a 205/55 R16, there are three different specificaiton, 91V, 91W, 94V.
If you ever installed new tyres with shiny wax on it, that’s when you should be concerned of. Tyre manufacturers will never spray / apply shiny wax on the brand new tyres.
I will try to compile images for another article on spotting brand new tyre from used tyre.
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