Originally Posted by
colleen c
I'll be very lucky if I only have to put air in my tire only once a month. My 700x23 can lose 15-20 psi from 120 psi to 100 psi in one week. My 26x1.5 on my MTB drops from 75 PSI to 50 PSI in less than three weeks.
Yeah, I run 700x35s. I put air in them weekly, pumping them up to their max (100 psi) By the next week, they're usually down to 80 psi or so.
Just this past weekend, I went downstairs to get my bike for a Saturday AM ride, and the rear tire was flat. Took off the tube, inflated it to listen for leaks - nothing. Nothing in the tire either, and the rim tape still looked good. I carry a spare, so I just remounted the old tire as an experiment. After an hour riding, it was way down on air, so I just put on a new tube. I'm guessing it was a bad valve as someone above suggested is a possibility in these cases. New tube = no more problems.