Heres your answer:
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Race Director
Joined: Sep 2001
Posts: 14,676
Likes: 751
From: NEwhere Ohio
Heres your answer:
Ok, ill be the guy with the techincal answer:
The brown color you are seeing on the sidewall is from dialkyl/ or diaryl p-Phenylenediamines leaching to the surface of the tire sidewall and reacting with ozone in the air. A small amount (maybe 1-2% by weight) of the sidewall and tread ingredients by weight is PPD (the abbreviation for the chemical named above).
This chemical, although staining, is a very very active chemical species at thwarting ozone / (and oxidation) attacks on rubber compounds.
One nice thing about this chemical is it provides dynamic protection against ozone, while the tire sidewall is deflecting as you are driving down the road. Waxes are also added to the tire sidewall/tread compounds to provide static (unstressed) barrier protection against ozone/oxygen attacks.
If you did not have this in your tire sidewall, you would get little cracks in your sidewall. In fact, ozone attacks rubber so fiercely that older tires (where the PPD and waxes have almost totally evaporated from the compound ) may start to ozone crack. There are some strategies to getting around this though.
The brown color you are seeing on the sidewall is from dialkyl/ or diaryl p-Phenylenediamines leaching to the surface of the tire sidewall and reacting with ozone in the air. A small amount (maybe 1-2% by weight) of the sidewall and tread ingredients by weight is PPD (the abbreviation for the chemical named above).
This chemical, although staining, is a very very active chemical species at thwarting ozone / (and oxidation) attacks on rubber compounds.
One nice thing about this chemical is it provides dynamic protection against ozone, while the tire sidewall is deflecting as you are driving down the road. Waxes are also added to the tire sidewall/tread compounds to provide static (unstressed) barrier protection against ozone/oxygen attacks.
If you did not have this in your tire sidewall, you would get little cracks in your sidewall. In fact, ozone attacks rubber so fiercely that older tires (where the PPD and waxes have almost totally evaporated from the compound ) may start to ozone crack. There are some strategies to getting around this though.
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Joined: Nov 2002
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From: coolsville nj
Thread Starter
Race Director
Joined: Sep 2001
Posts: 14,676
Likes: 751
From: NEwhere Ohio
Re: Heres your answer: (GDP)
Sorry I messed that one up.
This is a response to the brown color that forms on tire sidewalls.
ha ha..that was funny whoever mentioned jeopardy.
The question would be: What causes a tire sidewall to turn brown.
This is a response to the brown color that forms on tire sidewalls.
ha ha..that was funny whoever mentioned jeopardy.
The question would be: What causes a tire sidewall to turn brown.
