Is it possible for perfectly sound tires to lose air (excluding someone deliberately letting the air out)? One of mine was almost flat about two weeks ago. I refilled it with air and it doesnt seem to have lost any since. If sound tires can lose that much air, why is that?
Yup, especially if mounted on bad wheels. Rims can be rusty and wheels can be pourous. Ford in particular had this problem with their cast wheels years ago. The problem has since been solved by wheel manufacturers.
Oh, and valves can leak. The stems are often removed for installation, and if they get firt on the conical rubber “sealing ring” in the valve upon installation, or of the stems aren’rt properly reinstalled, they can leak.
Have you checked the tire with a pressure gauge? It’s difficult to tell if a tire has lost pressure from a visual inspection only. In regard to a valve stem, the schrader valve can stick and leak air if it’s contaminated with dirt.
Have the tire checked for punctures, a small nail is easy to miss.
Dirt. Right. I wrote “firt”, didn’t I? Doggoned untrained fingers!
MB…use Firefox. Any misspelled words are underlined in red.
If there’s a nail in the tire or an issue in the bead area, it might leak only when the tire is parked in a certain position.
In any event, make sure to check this tire with a good tire gauge frequently. Also make sure your spare tire is properly inflated. (I always overinflate my spare tire, knowing that I can let air out if necessary when installing it.)
Most any tire will lose pressure over a long period of time. I’m thinking I’ve read that most tires will lose 1-2 PSI per month. Tires also lose about 1 PSI per 10* temperature variance, so if the last time you checked the air in your tires the outdoor temperature was 90* and the current temperature is 20* the tire would have lost approximately 7 PSI simply because of the temperature variation and if that was 6 months ago the elapsed time would amount for probably another 6-12 PSI. If you had 32 PSI 6 months ago, between temperature variation and amount lost over elapsed time you could easily have lost 13-19 PSI which would leave 13-19 PSI in the tire, likely making the tire look extremely low.
I’ve been kind of slack on it this winter, but as a normal rule I like to check the pressure in mine about once a month.