I just filled my stock 16" Dunlap Summer Run Flats yesterday to 33 per tire. I checked the tires today and both on the left were down to 30. Right were at 32.

Tires were cold when I filled them and checked them, and I used the same gauge.

Could the tires have lost 3 pounds in 1 day?

 

Did the temperature drop between when you filled up and when you measured today? You will lose 1psi per 10 deg c.

 

No. It's always 60 and sunny in San Diego in the winter.

 

The side w/ the now lower pressures was shaded. One side in the sun, one side in the shade would do this. Pull the car into a garare and you will see the pressures "return" to normal.

 

reason why i add a few extra pounds just in case.

 

You need to measure consistently. If you fill first thing in the morning after letting it sit overnight, you gotta measure first thing int he morning the next day after driiving same distance you drove to the gas station. I always put in 1-2 psi extra when I reach the station because the tires heat up even on a short drive. One trick that I use is to measure before I leave and then measure again at the gas station to see if they heated up at all.

 

Thanks! Next time I drive to the station, I'll add 2 extra lbs. The shaded/sunny explanation is brilliant.

 

Can anyone recommend a good tire gauge? For some reason, I don't trust those little chrome ones with the stick that pops out. Would definitely prefer a digital readout!

I got a false reading on the tire pressure sensor when i started up a couple of weeks back and it was bitter cold outside.

Thanks!

 

Definately dont use those old stick ones. The best one in my opinion is an accurate dial guage or digital available at some hi end auto stores or online. Dont get the small dial cheapies. Accuracy depends on the $$ you spend.

 

http://www.ioportracing.com/Merchant...&Category_Code

A little pricey .... but a well built unit that will display the pressure while bleeding air off.