30 30 is the lowest I would go and is really a nice track pressure. I recommend something around 32-33 for the street.
The manual pressure of 36-42 is called a "liability" recommendation. It is not a good street pressure, way too high. Good pressure for two three hundred pound riders though. At that pressure the bike will turn really easily, get slightly better gas mileage, wear out tires in the middle very quickly, and have very poor traction.
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