Cedarbat

This is an interesting Thread....allow me to throw in my own 2 psi.

I bought a pair of Vredestein fortezza SE tires several years ago, in part, because they were rated for 160psi max. I assumed that higher pressure was better, and I would routinely max them for competition events and fast group rides. The result is that I would and get "pounded" to death by every crack or divit in the road surface. They felt like they rolled much easier at the higher pressure, but there was definitely a "fatigue factor" involved. I continued to do this however, because I thought the pounding was worth the decreased rolling resistance, especially for triathlon events.

I took another look at the tire pressure discussions recently, however, when I bought a pair of used Zipp wheels which have a max psi rating of 125. There was alot of research out there indicating that there is at best diminishing returns, and at worst, a negative effect of pressures beyond about 110psi for rolling resistance, not to mention the forces it puts on the rim, especially under heavy braking. I thought back to my "beating on the bike" at 160 psi and it occurred to me that the reason I was getting pounded so badly was that my entire body weight, and the weight of the bike, was getting pushed upwards violently. That takes force or energy to do that, not unlike the additional force it takes to move a bike up a steep hill as opposed to flat ground. If a lower pressure tire can roll over the crack or divot smoothly and not have the same violent jolt or vertical movement, then the force required to lift the bike and rider is not experienced, and thus less energy is expended.

It seems to make sense to my pea-brain to think of it that way.