Originally Posted by
Retro Grouch
I'm in roughly your weight class.
On my Klein I used to run 700 X 23c tires at 100 psi front and 110 psi rear. On my Bridgestone with 700 X 28c tires I used 90 psi front and rear. for 700 X 38c's I'd use a little less air pressure - maybe 80 or 85 psi.
80 psi in a 700x38c is WAY overinflated. I'm 6'3", 185 lb and run my 650x38b's at 50 and 60 psi, and 700x25c's at 80 and 90. IME, optimal tire pressure is pretty much inversely proportional to width: ie, 38's are 1.5x as wide as 25's, so they should have 2/3 the pressure.
SP
Bend, OR