Frog in a Pot; a tale of tire pressure

[Joggernot]

Just found this thread. I, too, had experienced a shortening of my coasting distances and from another thread, noticed that tire pressure had a big effect on coasting distances. So, got out my gage and found that every tire was down to 38 psi instead of the 44 sidewall psi. Aired them up and my coasting distance has gone back up. Guess I'll have to check more often as the temperatures change. I don't have steelies and that might be part of my problem.

Joggernot

[justme1969]

Originally Posted by bbjsw10

I had same thing happen to me a week ago, just from temp changes. I have been running my 35psi tires at 40. Well it dropped about 30 degrees outside over last couple weeks. I check tires once every 2 weeks. Everyone of them was down to exactly 26psi. 14psi drop just from ambient temps, crazy never checked enough before to realize they change that much.

wonder how much barometric pressure effects them??? where is our physasist
lol cant even spell it ya know im not the one LMAO!

[RedDevil]

I regularly kick my tires on the threaded side, a habit taught by my bike riding instructor, but practical on cars too. Pong, pong, pud, pong. Guess which one is low.
Once you get used to it you can tell the pressure from the tone, though that tends to rise a bit with wear. It also gets easier.

[101Volts]

Yesterday I drove the 84 Caprice and aired the tires up to 40 hot, They were all down a few PSI. I hadn't driven the car for about a month when I aired them up. I have no idea how old the tires are so perhaps I should ask my uncle if he knows.

Originally Posted by RedDevil

I regularly kick my tires on the threaded side, a habit taught by my bike riding instructor, but practical on cars too. Pong, pong, pud, pong. Guess which one is low.
Once you get used to it you can tell the pressure from the tone, though that tends to rise a bit with wear. It also gets easier.

So that's why I saw that in a Back To The Future trailer. I never knew that before, Thanks.

Originally Posted by orange4boy

A real modding freak would check them every fill up.

Perhaps not that frequently, It depends on the car and the tires (Counting the age of them) and the driver and the amount of miles traveled; In other words, Timing. For me and for 100+ mile trips, Checking before the trip would help right now.

Edit/Update: I think the tires should be replaced some time soon. I don't drive the car much.

[user removed]

I check my tires often until I can see a pattern of pressures as well as any coasting reduction. The worst for loosing air pressure are tubed spoked motorcycle tires, probably the Chinese tubes are the biggest culprit.

The Fiesta and the wifes 2012 Sorento loose very little air over months. In fact this last spring as temps rose the pressures actually rose slightly as the air in the tires heated up, even measured cold. In fall it's the opposite, pressures drop as the air in the tire cools.

Fortunately the truck wheels, bought used and 15 years old, also hold air almost as well as the Fiesta and Sorento. The last time I had a tire loosing air faster than the others, it had a nail in it. I plugged it myself in the garage and now it holds air just like the rest.

If you have a significant loss of air pressure then when the tires are removed from those wheels, I use a abrasive wheel on my drill to clean the bead contact area of the wheel, then spray som paint on the exposed metal, also always use a new valve stem and check the area around the stem to make usre it is clean and smooth, use the same technique as the bead area of the rim.

Once I get a stream of data about my tire pressures on all of my vehicles, then I check the pressures less often unless I get a coasting reduction.

New cars with original tires seldom loose air pressure at any significant rate. Even after a year off the road, my salvage rebuilt Altima still had enough air in the tires to not set off the TPMS dash indicator. It also helps to have a compressor in your garage.

101 volts, unless the tires are very old, they should be date coded, so you can tell their age.

regards
Mech

[CapriRacer]

Originally Posted by justme1969

wonder how much barometric pressure effects them??? where is our physasist
lol cant even spell it ya know im not the one LMAO!

Yes, it does affect them, but, No, it is not enough to worry about. Less than a psi.

[101Volts]

Originally Posted by Old Mechanic

101 volts, unless the tires are very old, they should be date coded, so you can tell their age.

regards
Mech

Thanks, I checked them and I think they're older than 13 years, Including the spare.