Low Tire Pressure

perhaps the filling station system is broken?

you should always use a reasonable quality gauge, and check the tires 'cold' before driving in the morning

 

There is nothing going on with your car, but maybe there is something wrong with the gas station's air pump. Was the air temperature higher when you supposedly filled your tires with air? Certainly increasing temperature will result in a higher pressure in your tires as the molecules become more energized, and the opposite will occur as temperatures are lowered, but that should only account for a couple of PSI, unless we are talking about severe temperature changes. Is it possible that the gauge on the pump actually allows air to escape from your tires if it sees the pressure as too high. It shouldn't work that way, but maybe it is defective. It's probably worth trying a different gas station's air pump. Also, I always carry an analog tire gauge to check the tire pressures as I'm filling them with air.

 

I like to check my tires cold, before driving any distance. I bought a nice, cheap air compressor that connects to the 12v plug by the center armrest. I did a lot of research as I had to find one that used only 10A (good ones use 15A), but wasn't terribly slow either. I ended up using Tacklife M2. It is SURPRISINGLY fast. I top off from 35 up to 41 in less than 30 seconds. I wanted something j could use every month or so to make sure pressure is appropriate as weather temps vary a lot.

I usually over inflate my desired psi to account for slight loss when removing the connector. I then use a tire gauge that allows me to release air little by little til I hit the psi I want. I've been happy with 40/39 f/r and it's still very comfortable.

Link to the compressor I'm using. The blue one had a pricing error and got it for $25 on Amazon TACKLIFE M2 12V DC Digital Auto Tire Inflator Portable Air Compressor – Tacklife Tools

And the tire gauge I picked up from lowes. It was $5 during the holiday season as a stocking stuffer. I bought like 4 or 5 to have around.
https://www.lowes.com/pd/Kobalt-Digital-Tire-Gauge/50126544

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I agree with having a portable compressor. I have one of these... it runs off the cigarette lighter in your car. Loud; a bit slow; but gets the job done.

 

Was the gas station system broken, and let air out of your tires until they reached a too-low setpoint?

I use a bicycle floor pump at home to top up my tires. While it does involve a bit of labor, it is quicker than driving anywhere to top up, and it it guarantees that I'm setting cold pressure, not warmed or half-warmed pressure.

 

MAJOR MISTAKE.
You can NOT trust any "public" tire gauge like that.
Get your own.

 

Maybe it didn’t reach desired air pressure. I’ve dealt with anemic gas station pumps, barely enough oomph; they come to a standstill at some pressure. Maybe in your case that standstill was after some air bled out? Did you check pressures with your gauge, after “filling”?

See the above is close to what @fuzzy1 said. Also, I do the same as:

 

Since you are in North Carolina, has there been wild temperature swings? Like one day its 80 degrees and the next day its 40 and snowing?

Because if you filled up on a warm/hot day and the next day its cold, the pressure will be lower because temperature does affect tire pressures. Only fill up when the tires are cold and on cold days or when its not predicted to have a temperature swing.

 

have you rechecked it?

 

FYI. The compressor I'm using has a pricing mistake for the orange one. Amazon is doing 15% off by checking the box and you can also use the promo code : CND6TV3R. It will bring the price down to $24. It's not a bad price and it won't blow your fuse either. (I tried the viair and the 15A was too strong and blew my fuse. Tried a similar one and same thing.

Posted via the PriusChat mobile app.

 

Pic of the one I'm talking about

Posted via the PriusChat mobile app.

 

Few people actually have compressors; many have their own gauges.

Ask around of "tire shops" in your area.
There usually will be one or more that provides free air service......that really is free.
If you have your own gauge, you will know before going there if you actually need air or not.

 

I'm doubting this part, based both on past responses during my time here, and the common and very easy availability of such products from all the hardware / automotive / cycling places.

This part is true. But nearly all drivers should have their own gauges.

 

3 bucks to fill your tires? we gave up on that years ago. stations tried and failed

 

You might also want to check the valve core in each tire for tightness. And when you get all the tire pressures set to where you want them on a cold morning before the sun comes up, make sure you run through the dashboard TPMS reset instructions in the owner's manual to reset your calibration point.

 

People "on here" tend to be car enthusiasts and do not represent the public at large.
Doubt it all you want.
If you care, take a survey of random people and I think you will find that LESS than 1 in 10 own any kind of air compressor.

 

Stuff I’ve accumulated, with not a lot of effort or expense:

Car with a spare (yeah, pretty obvious, but apparently they’re getting rarer...)

BlackJack tire plug repair kit (used it close to 1/2 doz times now, on our Prius and other cars)

Various tire pressure gauges

Tread depth gauge

Floor-style manual bicycle pumps, two currently (fine for topping up car tires, just a little exercise. Even capable of bringing complete flats back up, post-repair)

Spritz bottle with some sudsy water (for checking for leaks)

Durable insulated gloves

Tire sized plastic bag (for tire storage and/or to lie on)

High-vis vest and collapsible traffic cone

Flashlight with magnetic base, with blink function.

Small square of plywood (to provide better base for scissor jack, on rough or soft earth)

Pair of wheel chocks (for wheel diagonally opposite the jacked up corner)