Originally Posted by
dksix
I determined the tire pressure was high due to the tire's max pressure being rated at 70 PSI and I pumped to 50 front 60 rear, that's 70% and 85% of max rated pressure. The tires were providing little to no suspension and wasn't getting very much traction in the small gravel on the hard packed dirt. I could have stopped and let air out until I got a more subtle ride and/or better traction but from there I'd have no way or accurately correlating that feel to an actual pressure value........but with a pressure gauge I would be able to establish an accurate and repeatable pressure value once I did reach the feel I wanted.
In another thread, there was a comment about squeezing the sidewalls instead of pushing on the tread with your thumb. (and ThermionicScott mentioned something similar in this thread). It does seem to be more accurate for me.
I've let out air in the middle of a ride, too. Sometimes because the roads were a lot rougher than I expected. About 5 or 6 fast blips on the presta valve is good. But I didn't care about the actual pressure -- if I remembered, I'd check with the floor pump at home. I will do the sidewall squeeze to try to remember what this lowered pressure feels like.
Jan Heine (I know, I know...polarizing) says
pressure isn't critical. But if I've dropped the pressure during a ride, I'm usually more careful about possible pinch flats on the rest of the ride.
from the link:
The reason is simple: Higher pressure decreases the energy required to flex the tire. Less energy is lost due to internal deformation (hysteresis). But higher pressure increases the losses due to the vibrations of bike and rider. More energy goes to suspension losses. The two effects cancel each other. Whether you pump up your supple tires super-hard or ride them squishy-soft, they have the same resistance.