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Old 01-11-2012, 07:24 AM   #24 (permalink)
CapriRacer
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Quote:
Originally Posted by niky View Post
Just a question... aren't donuts supposed to be inflated to about 50-70 psi anyway? So if you're using the other tires at their max sidewall rating, which is usually in the 45-50 psi range, wouldn't the equivalent for donuts be around 90 psi (my donut is)...
Except that donuts have a short designed lifespan - on the order of 50 miles - while regular tires are designed for a lifespan up to 100K miles. That means the casing for donuts is designed weaker and additional pressure is much more likely to cause fatigure problems.
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