Originally Posted by
cyccommute
Honestly, to get to 40 psi tire pressure at your weight you’d need nearly 2 inch tires. The other problem you’ll have at 40 psi on anything narrower is going to be with rolling resistance. It goes up significantly as you get to those kinds of pressures.
Can you develop that thought further? I'm 210 lbs riding 42mm tires at about 38 psi on trails, and I'd like to go faster. I can't brake 20mph top speed on level ground.