Sorry, I can't help you here. I really like these tires. I have 2 sets of the Kwest Hi-Pressure (100psi) 26 x 1.5" tires on one of my MTB's and my wife's MTB. We use them as our "path bikes". We haven't had any issues since June. The tires are of average "tightness" on the rim for me. Not so much as low air on them. I check air pressure every other ride and a squeeze check the rest of the time. I usually put in a couple pounds every other week or so. We put about 50-60 miles per week on them now. Maybe I'm just lucky.