Inside my door panel the sticker says what the tire pressure should be: 33 front, 30 rear. On the tire it says 41 psi max. When I inflate to 33/30, the tires look low, with a noticeable flat spot. Tires are the correct size for the car/rims, but are not OEM.
I have a pump that plugs into the cigarette lighter. It has a digital gauge built in. I also have a hand held brass dial gauge. They do not read the same pressure. Which type tends to be more reliable?
When I inflate to 33/30, the tires look low, with a noticeable flat spot.
This is normal. All radial tires bulge out a bit at the ground. The larger the contact area between the road and your tire, the better traction/braking you get. If you try to inflate it more, you will get a harsher ride and the tires will wear unevenly. You definitely don't want maximum pressure of 41 PSI. Bad things could happen when it gets hot.
Which type tends to be more reliable?
Probably the dedicated dial gauge. But the only way to tell for sure is to check it against a known pressure, or a calibrated gauge.
OK, thanks. I think I need to check my gauge, because I'm not talking about just a little flat. I'm talking about looking like it will bottom out if I hit a bump.
I know they say to check and inflate when the tires are "cold", but at this time of year, it can be 35 when I wake up and the car is in the shade, but later in the day it goes up to 65-70 degrees and I'd be driving in the sun. By "cold" do they mean not warmed up by driving? Should I wait till the temp is up to 60ish and the sun is on the car, but it hasn't been driven yet, or do it first thing, when it's actually cold?
Thanks!
yes. "Cold" means the vehicle hasn't been driven for a few hours.
Can you post a photo of the tire?
Is your car parked on a flat surface when you measure pressure?
Follow the manufacturers recommendation on the door jamb sticker when the tire are COLD.
