Inflating tires after driving to gas station

What I do is check the tire pressures cold, drive to my preferred gas station (it's maybe 2 km's), re-check to see if the pressures have climbed. Then when adding air, overshoot a little, by at least the amount they've climbed from cold.

To be real dilligent: check them the next day, when cold. Typically I won't bother though.

 

You could test it by adding 1 extra PSI when inflating when warm, then check them the next morning to see what PSI they settle down to and adjust from there. So if your tires are warm and you want 42 PSI, inflate to 43 and test after they've sat overnight.

 

So driving 4 miles each way to the gas station isn't using fuel?

If you're going to be that...fill in the appropriate word here...check a tire at home, then at the gas station, and you'll know the PSI difference.

 

Maybe he's consolidating trips. Personally I'd rarely if ever drive to a gas station just to add air. Typically we have chores nearby, stop into the gas station on the way. Come on

 

You can get a home outlet compressor pretty cheep, but wouldn't think the 12v. system is affected so much to cause significant mpg worry.

The reason I post is to say I hope people run the air from the station hose to see what comes out. Usually I see a water mist at first, don't want extra water in the tires. At a Chevron once, nice station too, literally a stream of water came out of the nozzle at first. That would have gone into the tire. In general I think the outdoor hoses at stations are not very water free, unless the owner has taken some care about it. The chances of that care are unknown.

 

At the end of my day I try to hit the nearest station from home and fill about 5-6 psi over what I want to read cold. I make sure I don't drive over 40mph for safety.
I re-check the cold psi in the morning before heading out.

ETA: I factor in the temp difference of my garage (40's) and the average temps for the season (20's) when measuring cold psi.
The basic formula I use is: "For each 10 degree drop in temp = 1 psi drop"

 

Even so, I'd be willing to bet that the extra gas required to get your car moving after stopping at the gas station, vs continuing to move and driving right past the gas station is many many times more than would be required to recharge the battery after running a 12V air pump for a few minutes. If you're that concerned about it, you can get a 120V air pump for under $50 and just plug it in to your house and not use any gas at all.

 

Buy a tire inflator.

 

PV=nRT :madgrin:

 

My air pump fuel is peanut butter and jelly, and it needs to get burned off the gut somehow.

But really, my rarely-used 12V pump has to pull less than 120 watts (accessory outlet rating), and runs 15 seconds per psi, for a net of 2 watt-hours per psi for all four tires. Estimating that the car uses 250 watt-hours per mile of travel, the electricity costs 42 feet of car travel per psi added. Bump that to 100 feet to allow for HV battery, DC-DC, and 12V battery conversion losses.

Are you going more than 200 feet out of your way to use the gas station air pump? If so, you aren't saving anything.

And that doesn't count any engine heat loss while sitting at the air pump.

 

My low pressure light came on. I put air in the tires and pushed the button 3 time but the light did not go off. any ideas on how to correct this?? [email protected] thanks

 

They sell 120V tire inflators.

 

20 minutes! What's wrong? Valve head leaking most of the air? Air pump not up to the job? Tires severely deflated, to the point of risking damage just driving to the station?

As I mentioned, my 12V pump takes 15 seconds per psi added per tire, and I don't let them drop more than about 2 pounds before retopping.

My bicycle floor pumps needs 7 strokes per psi, so it takes half the time of the 12V pump, and doesn't have a nasty cord re-stowing problem when done.

Yup.

 

Pump them up to 50/48 and then the difference the heat of a 4 mile drive won't matter.

Why not get a hand or foot powered tyre pump, remember those? They still make em!!

 

Oh, but that will use extra gas too, I'm afraid. He'll expend more energy using that pump than he would with a powered pump, then he'll get hungry sooner and require an extra trip to the grocery store.

(Sorry... I couldn't resist)

 

To reset the TPMS, you press and hold the reset button until the dash icon flashes 3 times and goes out (not press the button 3 times), then you need to drive for a while. Instructions in the owners manual.

 

It doesn't reset on its own after 'x' amount of time or miles of having the correct pressure in the tire?