Originally Posted by
Kapusta
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Go to any tire pressure calculator, and the two things they all ask for is tire size and rider weight. BOTH make a huge difference. Max/Min pressure is totally unnecessary for the calculation.
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Which would be fine in an imaginary world where all tires have the same tread pattern, tire compound, sidewall stiffness, and a whole host of other factors including the rim width. In that imaginary world, sure - you can just use the tire size and rider weight because those are the only two variables. In the real world however, different tires behave differently, even with the same pressure and rider weight. There's no "calculator" that can tell you what tire pressure to use, without knowing the specific tire (and rim) that we're talking about. 40 PSI on one tire/rim combination might give you equivalent performance as 55 PSI on a different tire and rim. That's all I'm trying to say, and I think it's sort of obvious.
The best advice for the OP is to simply read what it says on the tire, and experiment within those upper and lower limits to achieve the best performance for the conditions that he rides. Every tire and rim combination will behave different.