[Archish]

Hiya mates,

I m having funny problem with my cars. When ever i get a new car, i have tyre pressure problems. I got a siena about a month ago and got the tyres changed, every 2 or 3 days the tyre pressure would go down by about 2 or 3 PSI. I got the tyres checked by 3 different shops and there was no puncuture or leakage from the side or from the point by which the air is pumped in. Now, I got a Innova and I m having the same problem. The rear right wheel pressure seemed a lil low yesterday, so went and got it checked, it was at 25 PSI, the normal is 30 PSI. They checked for punctures and leaks, there was none. SO they pumped in till 30 PSI. Now, this morning again, all the tyres seems to be getting low on pressure. I m yet to go and get it checked.

What could be the reason? The only one that I could think of is, when we get our car out of our parking in our house, we have to turn the steeing wheel from right to left fully at a standing positon. I hope i m clear in what i m saying. Could that be the reason. IF so, only the front wheels should be affected, why the back wheel's pressure is coming down?

[GTO]

Archish,

Either a bunch of pranksters in your neighbourhood, or you are checking the pressure when the tyres hot (best done when cold).

[ascertain]

OK- we need a breakdown of information -
Tyre pressures fluctuating you say..? let's take a look at factors that affect Tyre pressures.

1) The Air pressure inside the tires support the weight of the vehicle right?.. so if you keep your vehicles loaded with stuff it'll cause a more rapid reduction in Tyre pressures.
Just try and recollect if you do let this happen. Do you park on an inclined surface? If you park on a slope, It should theoretically place more stress on the tyre set on the decline, shouldn't it?
2) Instrument error can be ruled out, since you have had the pressure checking done at different places.
3) The usual scenario experienced is the INCREASE in tyre pressures when you check it after running it down to the checkpoint.. since you say your pressures are DECREASING, it presents as an unusual complaint.


Please clarify on a few other points to add to the infobase
1)What brand / size of tyres do you use currently?
2)Did you get the tires checked in the morning (early?) , how far from your place to the check point?
3)How is your driving style?, especially over bumps and potholes?
4)What is the climate of your area?.. and where do you get the tires air-filled from (Home/pump ?)
5)Have yo noticed any seasonal variations in your predicament?

Usually,
All things being equal, a tire's inflation pressure will go down by about 1 psi every month. This means that if air isn't added for two to three months, the tire's inflation pressures will probably be 2 to 3 psi low.

Since typical tire pressures range from 30 to 35 psi for cars (with light truck tire pressures often higher), there is a constant force trying to push the air through the tire. This allows some of the air to escape (called permeation) right through the microscopic spaces between the rubber molecules. And somewhat like a rubber balloon, the air will eventually escape if it is not replenished

At the airl filling station, using air permits moisture and the amount of water vapor in the air varies from place to place, time of the year and due to weather conditions.So if you do reside in a warm and dry climatic environment, water vapor goes out, and you have lesser pressures.

Now I think the BHPians will put apiece a probable explanation.

[sjcherian]

Ascertain has asked all the right questions :-). We have to wait till Archish comes back - this is a curious case of the low air pressure.
Only thought I had was to check did you fill air after driving for a while in which case the pressure of 30 which you saw was probably due to the heated air in the tires with the resulting cold pressure coming in at 2-3 lower. Try filling air when your tires are cool - not after it is driven. Max you should have driven under 2-3 km before getting your tires filled. Have been guilty of this :-) thats why.

[sgiitk]

My Accent loses about 1-2psi a day in a couple of wheels after I switched to Tubeless Tyres (Hyundai Alloys). Finally traced the problem to a slow leak in the rim-tyre bead seal. No solution, just have to live with it.

[Jaggu]

Always fill air before the tire has warmed up = less than 1-2 kms of sedate riding. This will give you best results.

In my car the tires lose around 2 psi every 2 weeks of usage, i feel this will be better controlled if i move to Nitrogen. Unfortunately dont have any nitrogen filling stations nearby so have not done the same.

4-5 pounds in a day or two is not ok though.

[adc]

Originally Posted by Jaggu

Always fill air before the tire has warmed up = less than 1-2 kms of sedate riding. This will give you best results.

Sedate driving to the electronic air filler pump of around 1.5 km is what I do and fill up to the psi according to the manual.

Now today seeing this info on the BF Goodrich website - 4 psi extra! that much or is it for this particular brand of tyre?

Checking pressure when tires are hot:
If pressures are checked after tires have been driven for more than three minutes or more than one mile, (1.6 km) the tires become hot and the pressures will increase by approximately 4 psi. Therefore when the tire pressure is adjusted under these conditions, it should be increased to a gauge reading of 4 psi greater than the recommended cold inflation pressure.

Source: BFGoodrich Tires | Tire Safety

[ascertain]

Originally Posted by GTO

Archish,

Either a bunch of pranksters in your neighbourhood

lol.. a most obvious point to be looked into.. in that case - guard dog!

[Archish]

I can assure u of no pranksters. My house is a individual house with a fenced gate and walls. So, no issue with this.

Im a very cautious driver and my part of chennai's road is quite good. Not silky smooth, but good none the less. I filled nitrogen in Siena. Then when i filled air, it was fine. Yesterday I did the same with the Innova. Till now, it seems to be good.

I know some friends of mine who live with problem of tubeless tyres deflating 2 or 3 psi in about 3 or 4 days. I guess the problem is with the tyre. I have brand new Michelin on Siena and Good Year on Innova.

There seem to be quite a few ppl in this forum who have similar problem. So, this brings us to bigger question of 'How much tyre manufactures test tyres in Indian conditions'

Anyways, I get wobbling in my Innova above 110 kmph. So, gonna get tyre aligment and wheel balancing done. Will deflate all the tyres and pump in pure nitrogen and see how things go.

[janitha]

With my tubeless Goodyear, there is a loss of an average 2 psi every 3-4 days. Earlier, when using tubed tyres, checking pressure was once in a month or so.

[CrackedHead]

Originally Posted by sgiitk

My Accent loses about 1-2psi a day in a couple of wheels after I switched to Tubeless Tyres (Hyundai Alloys). Finally traced the problem to a slow leak in the rim-tyre bead seal. No solution, just have to live with it.

Is the rim edge damaged ? If not, then removing the tyre from the rim and refitting it should have taken care of the problem.

Another option would be to try the can type "emergency puncture repair" sealants - that might take care of the leak.

My tyres have experienced similar pressure drops - 2 PSI in a couple of days. Its happened with Goodyear GPS 2's and Michelin XM1+ also (both running on steel rims) - but the cause was always traced to small puncture's.

Once I get that attended to, they hold air well (for over a month).

[newbiedude]

Hi Guys!!!

I have been driving a Maruti Swift Lxi since May 2009. Of late I have noticed a wierd problem. A few days ago I noticed that my front left tyre was losing air regularly. Accordingly I took it to my roadside tyre pressure walla who detected two punctures and repaired them accordingly.

Today I had gone there for a routine tyre pressure check and was surprised to note that the front left tyre again had low pressure. while the other tyres were maintaining a pressure of 33psi the front left tyre had an abysmal 15 psi.

Thinking I had another puncture I asked the same to be checked and was surprised no end to be told that no puncture exists. I havent mentioned earlier that at the last time I had changed that particular tyre I had installed the stepny. It has barely been a week since I did that.
a little bit of help here would be most welcome.

Thanks in advance for all who try.

[Jaggu]

You mean to say second time it was the stepney that showed the low pressure? If so did you check the air pressure of stepney when you fitted it?

[SPIKE ARRESTOR]

make sure the tyre is sitting properly on the alloys, an improper bead seat profile can also result in loss of tyre pressure, also there are chances of very minute punctures in your case.

Spike

[newbiedude]

Originally Posted by Jaggu

You mean to say second time it was the stepney that showed the low pressure? If so did you check the air pressure of stepney when you fitted it?

absolutely! when I change a tyre I immediately check tyre pressure and when the punctured tyre is repaired and turned into the stepney I try and maintain at least 5 psi above the required. I believe that is what is supposed to be done.