Do you weigh 150lbs or 250lbs? Will you be carrying 4lbs (64oz.) of hydration or only 2lb? Some here would say it matters. I don't. Following the KISS principle I note that your bike is OEM shod with Nimbus II Sport 2.3" clinchers with a psi range of 25 - 50. You couldn't go wrong putting 40psi in each tire and calling it good. Happy trails.