Help-- What could tires (new) tires to lose psi so quickly?

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Mar 14, 2004
I got some Yoko ES100 tires 205/60R14 for my 14x6.5" rims about a week and a half ago. I checked the cold air pressure the day after, and it was about 35 psi all around. I've driven the car about 130 miles since. Today, I checked the pressure again and they're all in the 30-32 range. What could've happened?

Is it possible that all 4 tire beads weren't seated correctly on the rims? Also, these tires have fancy metal valve stem caps-- are these more prone to leak air?
I would say it is probably from temp/ pressure change. If all 4 tires changed I wouldn't be too concerned. Check it in a week and if they are all in the 20's then u might have a problem
It was cold when I checked the tires a week and a half a go. if anything, it was warmer today than it was then, and pressure is still down. I live in SoCal, so temps don't vary that much.

Anyway, if pressure is down next week, what might be causing the drop?
Nothing happened, I usually see a 5psi drop every week for a couple/few weeks until a new tire finally settles in.

So you're saying the pressure will eventually stabilize? This is normal in new tires?
Nice tires. I've used them in the past. In my experience, screw-in metal stems are easy to install incorrectly if the tech is not familiar with them.

In your case, like others mentioned, it doesn't sound alarming, yet. Check the pressure early in the morning before the sun hits them (if your in a garage, all the better) and compare results over several days.

The other thing is to make sure you are using a good tire gauge. A $1.50 gauge from WMart may not be consistent, and probably not accurate

Originally posted by DaveInLA:
So you're saying the pressure will eventually stabilize? This is normal in new tires?

I just put on new Michelin Exalto A/S's yesterday and they seemed to have dropped a pound overnight from 32 to 31 an even 30 in 1 tire..I think there may be some truth to what GMguy is saying.

Seems like every tire I have ever had has never been quite right for a little bit right after I have them installed...either a little jittery, losing some air, rough in point...I bought some Goodyear Comfortreads back in December...never felt quite right..after a few weeks they started to feel pretty smooth....discovered the knumbskulls at Town Fair Tire put 3 of 1 size on my car and 1 of another
When they replaced it with the right size the jittery unbalanced feeling came back. I went to another dealer(Sullivan Tire) and asked them to balance the tire...guy spun it up and said it was dead on...he said that tires need a bit of time to adjust to the vehicle they are on, let the bead set, basically wear in bit...was he feeding me a line
Dunno...I didn't listen to him and swapped them out for some Michelin HydroEdges....

This time it was felt great right off the bat but a week later they started to feel rough and unbalanced...had some issues with the psi also being high low, whatever..never seemed to stay constant..rather than run to the shop again to say that my tires are out of balance(ok I did
but that detracts from my I have one?) I just put miles on the time I bought my alloy rims the Edges were running nice and smooth(loud as anything buy smooth)

Kept the Edges on my steel wheels and bought the Exalto's to put on my alloys....same deal as the Comfys..these tires feel pretty jittery on the highway with vibes in the wheel and gas pedal...I'm going to hang in there and just put miles on them based on my experience with the Edges and what the Sullivan tire guy told me...hopefully they'll follow the same course as the Edges and smooth out

Sorry for the marathon post just to say...yeah, new tires seem to need a learning curve..then again I might not now what the heck I'm talking about either


In my experience, screw-in metal stems are easy to install incorrectly if the tech is not familiar with them.

They seem pretty easy to install-- what's there to mess up? You screw on the cap until it's snug, right? Am I missing something?

I am using a cheap tire pressure gauge, but it's been extremely consistent for me before. Between my E30 BMW and 2002 Altima, tire pressures have always been within 1 psi each time I check.
"...what's there to mess up?..."

Actually, quite a bit.

There are different diameter holes and with a snap in valve it either fits or it doesn't.

But there are 5 pieces involved to mount a screw in valve and if the guy doesn't get the outside rubber seal correct, when he tightens up the nut or doesn't use the washer, he'll distort the rubber and it increases the air loss rate.

BTW, it is common for tires to grow, especially in the first 24 hours after mounting. You can lose 3 psi just due to that growth!

And more info, that might help! Most of the normal air loss that is experienced is not through the tire, but from the tire / wheel interface (the bead / rim flange) and the valve hole / valve interface.

Hope this helps.
Don't worry about the beads not seated correctly, there is really no way to mess that up if the wheel and tire are the same size. If you are worried, then look all around the bead where it meets the rim, if not fully seated there will be a gap between the tire and the rim, a gap of maybe 1/2 inch or so. Tires are usually installed with a soap and water solution to facilitate bead sealing. I've never seen it done otherwise, I suppose the tech could have forgotten it or just run out of it and was too lazy to refill the little bottle on the tire machine.

Otherwise, I'd say this is normal, give the tires a few weeks and they should stabilize.
CCD--when you say stabilize do you mean just the tire pressure or the whole tire itself as far as vibrations, smoothness, bite etc..? I'm just trying to back up what the guy at the tire shop told me..I have to go back today to get the lugs re-torqued and was wondering if I should let him know that the ride is sort of blah and bumpy...


Originally posted by DaveInLA:
....Anyway, about the metal screw in valves, I'm wondering if we're talking about the same thing... the part that sticks out of the tire is rubber (the "stem"), but the cap that screws over it is metal. You're saying there are 5 components to that part? [/QB]

No, it doesn't sound like you have metal valve stems. It sounds like you have a rubber snap in valve with a metal cap.
Every valve stem I've ever seen has been rubber. I didn't know there were metal valve stems out there!

I was just wondering if the metal caps form any less of a seal than the rubber/plastic ones do, that's all. I took a look inside the cap today and saw a small rubber/plastic ring. I suppose that's supposed to form the "seal".

Anyway, I'll wait a few weeks and see how the air pressure does.
Goose, I mean stabilize in the sense that a tire is constructed of many, many belts of different materials, different rubber compounds along with quite a few different pieces of rubber that have been "melted" together. When new tires are first put on a vehicle, expect a little wiggle in the tread and a little air loss for a day or two until everything sorts itself out. Just like every other thing with many pieces and a complex production process tires have a short "break-in" period. Short is the word, no more than 3 - 4 days and they should stop leaking quickly and start leaking slowly.
I've been mounting/balancing/selling tires for 30+years,, STILL have a lot to learn. Several different issues here.

1. New tires will actually shift,turn,rotate, on wheel after first installed. Inital balance at time of installation is mostly a waste of time, except you want your new tire to be smooth when they leave my shop. After couple thousand miles everything's pretty well where it's gonna stay and second balance will usually last rest of tires life (unless you slip tire's position on wheel by spin/grab acceleration or slide/grab braking).

1a. Inital slippage is mostly caused by lube used to seat beads, but it's a necessary evil because otherwise there is a real risk of tearing bead rubber!

2. Osmosis, the phenonomon(sp)of air actually dissapating through tire. Many tire manufacturers are now recomending use of nitrogen instead of compressed air (it's not and shouldn't ever be compressed oxygen). Many benefits of nitrogen, do a Google search. NO I DON'T sell it at my shop. Not enough demand and equipment is real expensive!

3. Drop in ambient temperature greatly accelerates osmosis, but when temps warm up tire don't "grow" air back (not refering to temp change due to use).

4. Quality tire gage--AMEN!!

5. Valve stems, rubber by far most common. In 1970 we paid .30 ea. now purchase for .13 ea!!!!If using rubber, stem should be replaced every time tires are replaced. Brass or chrome plated brass stems are usually a life of the wheel investment. Installation should be done correctly but it's not rocket science.

5. Valve stem cap, Regardless of metal or plastic construction it's ONLY purpose is to keep moisture/trash out of valve core (the little thingie that's screwed out to deflate the tire) poorly seated valve core's are a large % of "flats" that we fix. The old procedure of spitting on your finger and wiping it over hole in stem still works just as well as it did for your gerat grandfathers (still just as disgusting to watch though, especially if gramps has a chew of REDMAN going!) Soapy spray bottle's more scocially acceptable now. Try this procedure before taking tire to repair shop for slow leaks.

As I said earlier I'm still learning and will be glad to pick up information here that will make my ocupation easier! Apologise if any spelling or grammar offends anyone. Most of my education has come form the SChool Of Hard Knocks (life)

Thanks Bob, good info.

I never knew that the tires had to be re-balanced. When should this be done? I'm scheduled for a rotation at 5K miles but there's no mention of balancing.

On that note, when I was under my car, I noticed that one particular wheel had a wheel weight on the outside of the rim AND the inside. They weren't they were about 90 degrees apart. I was wondering why a single weight couldn't be put kind of between them, and only on the inside of the rim. These weights are UGLY.
Put em all on the inside called "Static" ballance. Basically what the old bubble balancers do. Inside and outside called "dynamic". The only reason for me to give $5,000. plus for a computer balancer! But I can set my 5k balancer to do a static balance, like a $250.00 Harbour Freight balancer if you want them PRETTY!

While I know the difference in static & dynamic, I'm not educated enough to teach it here. Besides it'd probably get kicked off board for taking too much room! Do a Google!

Free rotate is common. Free rebalance much less so. The only way a shop can "give away" time and services is to find real or imagined problems that they can get you to allow them to fix at regular rates.

Not a matter of "had to" as much as do it if you feel vibrations. Not EVERY tire and rim have slippage. If you can get them to throw in rebalance with rotate, go for it. but if YOU feel vibrations above 55mph it would probably be to your advantage to pay for the service if necessary. If there's no vibration save your money and your service provider's goodwill.

Bob- That is more info on tire balancing in 1 reading than I have ever read in my life...thanks!

I went back to Sullivan Tire to have the lugs retorqued..while there I mentioned that I have some pretty nasty vibes at 60-80mph and would that go away once the tire was broken in...he sort of looked at me odd and said let's take a look...sure enough he came back and said 3 tires were oob and needed a bit more weight. When he was done after the test drive he pretty much told me what you mentioned regarding slippage and how the initial balance is almost a crapshoot and that my tires may have slipped on the rim a bit(he said something about Toyota OEM rims being slippery to begin with
) Mentioned the same thing about the lube can sometimes cause slippage but needed it..(are you sure you were not in Nashua NH today ?
) He said that usually the balance gets dead on when either the customer comes back because of the vibes or rotation time.

I any event the tire feel 100 percent better. It is a High Performance tire(Exalto A/S) so you do feel a bit of the road but I imagine that is how the tire is designed...grippy so you will feel more of the road than a T rated touring tire correct?

Thanks again, your knowledge has been fantastic!


PS CCD thanks for your words of wisdom also!

PPS Guys, once you find a good tire shop stick with is worth maybe a few extar dollars to get the job done right...kudos to Sullivan Tire of Nashua

And more info, that might help! Most of the normal air loss that is experienced is not through the tire, but from the tire / wheel interface (the bead / rim flange) and the valve hole / valve interface.

Yeah, I'm worried that he didn't seat the beads correctly.

Anyway, about the metal screw in valves, I'm wondering if we're talking about the same thing... the part that sticks out of the tire is rubber (the "stem"), but the cap that screws over it is metal. You're saying there are 5 components to that part?
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