Originally Posted by Roxter
Actually 120psi for road tires isn't too much. In a road tire you want to have the most psi to have the least amount of tire on the ground which equals less road resistance. i pump my road tires up to 110 psi and my xc tires up to 60 psi. The rims just suck if they bend when you hit a bump that small.
Depends on the roads and trails. On rough roads I like to have my road tires at 95psi to take the edge off, on the trails my hardtail is much better mannered with 36psi in the latex tubes. Believe it or not but scientific testing has shown that lower pressure can REDUCE rolling resistance. If the surface is rough the upward deflection caused by going over bumps produces less resistance when it is more fully absorbed by the tire rather than causing the bike and rider to move upwards. Think of how much energy is expended lifting you and your bike up a mm or two, now multiply that by all the little surface irregularities you encounter. It adds up to a lot of energy over a couple of hours.
Back on topic, I too believe that bikes are starting to plateau in terms of tech, it seems that things are just getting slightly lighter now. With that said, IMO newer is better, but perhaps not by enough to upgrade every couple of years.