I run mine at 110 psi, but that is what the tube and tires are rated for, or actually more. I will usually lose up to 5 pounds of air a week in my tires, don't ask me why, but some weeks it is more in the front and some weeks it is more in the back. I close the presta valve the same way each time, but it still different each week and yes you can really tell the difference and I can tell the difference when I am riding on my rollers also as it is much tougher.