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Originally Posted by trikkonceptz
Great reply Capri, but that opens up a couple more questions.
What enviromental factors contribute to aging a tire prematurely? Heat, Load, use?
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All of them.
Heat is by far the biggest contributor to tire aging. Some refer to the Arrhenius equation (wikipedia that!) which says that for every 10 degree Celsius increase in temperature, the reaction rate doubles. This means that hot climates will age a tire faster.
Then there is stress / strain. Stress would be analogous to the load on the tire and strain would be the load vs inflation pressure (or deflection) of the tire. Needless to say, the deflection also adds heat generation on top of the ambient temperature.
Speed is also a factor as increasing speed increases the rate of heat generation.
After that we get into all kinds of things that contribute to heat generation and stress and strain - hard cornering among them, but if we confine ourselves to reasonably normal car usage we can neglect these.
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Originally Posted by trikkonceptz
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I am sure some of these factors can be traced back to improper inflation, meaning low tire pressure, which induces riding on the sidewall for example. Or can we throw in temperature extremes like driving in Florida during the summer, or a winter in Green bay.
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Funny you should mention Green Bay. I had a discussion today with a chemist on cracking in white sidewall tires. This is almost strictly a cold weather phenomenon and it is due to the way white rubber compounds are formulated. This is not normally a problem when carbon black is used as a reinforcing material.
Quote:
Originally Posted by trikkonceptz
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Does lack of use contribute to said failures ......
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Yes, in that AO's will tend to migrate to the surface as the surface AO's are used. This is promoted by flexing of the rubber compound. An analogy would be the Partial Pressure of Gases (another thing to wiki!) except that we are talking about a mixture of solids. The easiest way I've discovered to envision this is spaghetti in meat sauce, where the spaghetti is the long change rubber compounds and things like AO's are bits of sausage in the sauce.
If the AO's are used up on the surface, the surface will tend to crack and no flex considerably slows the AO's migration to the surface.