I keep the tire pressure in my tires at approx 40 lbs per tire. I have an inexpensive tire gauge that I use to measure the pressure. Recently, one tire seemed low, so I measured the pressure and the batteries were dead in the tire gauge. I replaced them and measured again.It said 20.5! I thought I was going crazy, but then measured all the other tires and they were around 35 to 40. I filled up all the tires to about 40, but when I measured the weird one again, it said only 30!The question is, could there be a problem with the tire valve that is preventing me from getting a good measure of the pressure? I filled up the tire to where it looks really filled up, and I'm afraid to overfill it. I'd like to get it to 40 lbs but I don't know if it's already gt; 40 lbs with a tire valve problem. Or if a tire that's at 20 pounds can look so filled up that you couldn't tell it from a tire that's at 40 pounds?Any info would be appreciated.
Overinflating your tires beyond what the people who designed, built and exhaustively tested your vehicle recommend because some anonymous nut on a Prius owners forum says to is stupid. Over-inflated tires wear out more quickly which more than cancels out the fraction of a percent of mileage improvement you MIGHT see by doing this. Over-inflated tires also provide less traction thus reducing safety. Over-inflated tires are also more prone to damage from road hazards such as potholes which again could result in having to buy tires prematurely. What you are doing is a false economy. Do what the people who built your car and built your tires (ie: the professionals) recommend and inflate to 35 psi front, 33 psi rear. As for your gauge reading problem, if you are unsure you are getting accurate readings take it to a tire shop for a second opinion by people who do this stuff for a living. They should be able to figure out if you have a problem or not. You can't trust what the tire looks like. A tire can be underinflated by as much as 20 psi and still look OK or grossly overinflated to the point of being dangerous and you wouldn't know by looking at it.
you dont have to take it to a mechanic for a tire problem. take it to any tire place.. les schwab, cooper, anyplace that does tires... have them replace the valve and clean up the bead on the rim. It should only take 20 minutes and cost maybe $5.
by the time you drive around find a valve stem tool and then find a new valve core which you need to replace because it is leaking and how many times in your life time will you ever need this tool again you would be better off going to walmart tire center and have them install a new valve stem it comes with the new core and cap in 1 unit assembly
Get rid of the battery powered one try the old mechanical pressure one. 40 psi sounds a bit much unless it's a truck. On the drivers door, there's a sticker which says what the pressure should be for that car w/ that size tire on it. I advise you follow the recommendation. The vehicle was designed w/ that tire in mind to get the best performance fuel economy. If the valave is bad, simply change it out. Go to a professional tire store before you do that. It could be more than you think.
The tire valve won't cause a poor reading. If there is air leaking when you test the air pressure, you can get a low reading. Hold the guage square on the valve and if you get a reading and don't hear air hissing while you are getting the reading, the guage will be right. Trust it and fill up your tire.
