How do I best add air to my tire?



That’s all been explained to them . . . by the supervisor(s), nonetheless

they don’t want to hear it

I can’t people who don’t want to listen to reason :frowning2:


It’s a highly personal choice, but if I were the owner of the shop I wouldn’t want them working for me. The liability is just too great. And if something tragic did happen that could have been prevented, I don’t know if I could live with myself. Too often tragedies are a convergence of bad practices and opportunity.


Well, considering I’m a civil service mechanic . . . the concept of shop owner is a little different

Exactly who would that be?

The shop supervisor?

The mayor?

Director of fleet services?


Wow this is as bad as when to change oil. The cold pressure refers to the pressure when the car has not been driven, not the temp outside. Driving will heat the tires up a few pounds is all. So just drive to the gas station and add the air. True in the winter the cold weather will cause the pressure to go down so need to add air then usually. You aren’t going to pop the tire at 30 + but 25 is way too low. Also, especially in the winter, after putting air in, just push the valve in for a second or two to let some air clear the valve of any debris or moisture.


interesting, never thought of that…


To fill in some of the gaps:

The pressure it takes to have a passenger car tire explode is over 100 psi - unless it is damaged.

The inflation pressure specified by vehicle manufacturers (on the vehicle tire placard) for cars is 35 psi or less (with a few exceptions.)

When referring to cold tire pressures, it ALWAYS means ambient conditions.

Yes, the pressure will change with the outside temperature, but within the same day, it doesn’t change enough to worry about.

Yes, a tire generates heat and that affects the inflation pressure. The rule of thumb is no more than 10% - so we are talking 3 psi for a car.

The max pressure listed on the sidewall of a tire is exactly that - a maximum (and there are a few exceptions). Do not use that value for anything else.


Maybe where you live…and if they do…sit in the waiting room 1-2 hours for a 5 minute job.

Knowing how to add air is something every driver should know. All the air fill places at gas-stations that I’ve seen you can set to the pressure you want and then it will stop when the tire reaches that pressure.

The pressure on the door jam is the pressure you use. I usually add a couple pounds more.


you wonderful folks talking about going off the door jamb stickers:

what if your tires/rims have been replaced with low profile tires, bigger rimes, lifted, or such? Door jamb stickers wouldn’t account for that, and would be rather inaccurate, would they not?

Checking tire size on the door jamb is almost as important as checking the tire pressure- in other words make sure the sticker actually applies to your tire before trusting it.


Then all bets are off. However the vast majority of people don’t do that. If you’re technical you can actually figure out the correct tire pressure. Tire pressure has a direct relationship between tire optimal footprint and weight of vehicle.


We are extremely fortunate to have a tire engineer as one of the regular contributors to this forum.

You already met him in an above post…[quote=“CapriRacer, post:46, topic:106243”]
To fill in some of the gaps:

The pressure it takes to have a passenger car tire explode is over 100 psi - unless it is damaged…

CapriRacer, also goes by Barry, of Barry’s Tire Tech.

He knows everything about tires, the “care and feeding” of tires, and is friendly and helpful. Check out his website and check these credentials…
CSA :sunny:


I made the assumption that someone who does those kinds of upgrades knows how to check the tire pressure. Of course, I probably shouldn’t make these assumptions, so I appreciate your comment.


This also assumes that the current owner is the one that made such modifications. :slight_smile:


I, too, made the assumption that we were talking about the OE tires. My bad!

But the vehicle tire placard always has the size - although some folks don’t make the connection.

AND - usually a plus sizing winds up with tires of the same load index - so, no change in pressure. Occasionally that is not the case and a different pressure would be called for.


Good post OP. You are wise to ask for help. I have driven test cars with pressures as high as 60 psi, so you are not alone in not knowing how this all works. Here is a succinct overview with images that makes it pretty easy to understand. People have been killed by over inflating tires, though it is very rare. Spares are the trickiest, since they require very high pressures. I wear safety glasses when I inflate those. You are not likely to pop the tire at the local station. Almost all have some sort of device that limits the pressures. Most also have an indicator of some sort, so if you don’t have your own gauge, you can get pretty close. BTW, if your car is a modern Nissan or Infiniti, the car can beep for you when you are filling them and the pressure is at the right psi. See your manual.


A friend told me that a pretty girl asked him to put air in her car’s tires because she was worried about over-inflating them. He paid more attention to her than the tire so blew it off the rim; he was a gentleman and replaced her tire. You are pretty enough to have this effect so be careful about accepting the help of gallants.

If your father inflated a bicycle’s tube with a gas station’s pump, he made a mistake all the bicycle-persons advise against.

When you include the time it takes to make a trip to the service station, it’ll be faster to inflate it yourself. A pump will add about a pound for 20 strokes to a small auto tire; I can pump once per second. Mine lose about a pound/month: 80 seconds of pumping monthly. Plus driving to the station warms them up.


I wouldn’t say that. I had a friend whose tire pressure light came on after their friend had borrowed the car and didn’t have a gauge to check. Once we were able to meet up that evening I checked the tires. Three were close enough to 35 that there weren’t any issues. The fourth tire however was so inflated that the gauge fully extended in an instant. After about 2 minutes (combined from stopping and checking) of letting the air out with the back of the gauge we were finally able to measure it at 50 psi.

That being said, always make sure people check their pressure. It solves airhead moments when thinking obviously hadn’t happened.


Kamaron.woods said, "I wouldn’t say that."



I’m going to vote that we keep this board from closing.

People who ask questions on this board are our customers. We are the volunteer information desk personnel.

If we keep directing our customers to get their questions answered elsewhere, we will be out of business.

I’m not interested in pursuing that goal.


This isn’t a business. It’s simply a forum to try to help people with their car questions. If the best response is to suggest they seek out a good shop, we help them better by giving that response.
If you call a doctor with chest pains and he/she tells you to go to the emergency room, is that a bad doctor?

Besides, who suggested that we close the “board”?


I agree. I do not believe the best response is ever going to be “Google it.”

No one suggested that we close the board, but if we answer questions with, essentially, “go away and google it; you’re bothering us,” then it will eventually close nonetheless due to lack of participation.

To get a little more detailed on why “google it” is a bad response beyond driving users away from the board, Google doesn’t really scrutinize all of its search results for accuracy. Neither does YouTube.

If OP googled it and found some dope who said you should always fill the tire to the pressure listed on the sidewall, that wouldn’t help at all. They’re coming here to get actual humans who can evaluate whether or not advice is good, and disagree with each other when it isn’t. They can’t get that kind of fact checking from Google unless they already know what to look for.