Quote:
Originally Posted by Sirref
So today I went out on a fairly aggressive street ride through my favorite 100mi course of windy back roads. The weather was pretty hot
...after the front tire was brown in the center line and the rear was brown on the sides. Does anyone have any idea why this would be the case? I haven't seen this before.
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Quote:
Originally Posted by csmith12
You got the tires crispy! 
.......There are oils in the rubber of the tire. Depending on many factors (mainly heat), your tires will change color because the heat brings the oils to the surface of the tire. That oil then mixes with whatever your riding on, dust, dirt, ect.. ect.. |
What cssmith says about the natural oil in the rubber is true. Tires do tend to turn brown. It's called browning or "blooming". There's a chemical tire manufactures use called Antiozonant. It helps prevent rubber degradation (cracking, splitting, oxidizing, and overall deterioration) due to the rubber’s interaction with ozone. The tire rubber is designed to constantly work the antiozonant to the outside of the tire as it rolls – in this way, the outside surface of the tire is continually replenished with fresh antiozonant. It's not necessarily heat. Tires will brown in cold weather too.
The negative result of having antioznants on the tire is tire browning – once the antiozonant gets exposed to the ozone in the air, it turns brown due to oxidation. Combine that with brake dust, road grime and dirt, you get a brown tire.
Want to age a tire prematurely, have it with cracked sidewalls? Leave it dirty and coated with metal flakes so that the rubber can't "breathe" and dry out.
Did you really get your tire that hot to turn your tire brown with a little aggressive street riding in low 90 degree weather? Probably not.
Do you clean your tires regularly?
Just simply cleaning the tire and buffing it with a clean rag can bring the natural black luster back to the tire.
Will all the brown come off? Maybe, maybe not. It will depend on the tire.