Unexplained tyre deflation

slade_x

About a year ago, i suffered a puncture or what i thought was one, i noticed it one morning before even taking it out for a drive so i re enflated and left it for about a half hour and it seemed to have held the pressure, so i took it to have it checked out. i was told the tyre was fine. i was recommended to see an alloy wheel specialist for any cracks or hair line fracture's so i did and was again told they could not find anything wrong with the wheel, the tyre and its seal.

so i accepted that assessment, had the tyre taken off and put back on with new valve just for the sake of it and drove cautiously, no long drives for weeks after, it has been perfect ever since, its about a year later now and the same thing just happened again. i went for a 20 minute drive to pick up my girlfriend (her cars being serviced) came back parked the car and then about 3 hours later returned and the tyre was completely flat . i have just reinflated it about 2 hours ago and it seems to be holding yet again. obviously im going to have it looked at again but has anyone experienced anything like this.

I know its not vandals deflating my tyre and i havent hit any potholes lately as far as i can remember it makes absolutely no sense handling has been perfect, i always feel if tyre pressure is a little suspect in my previous cars because its always obvious in handling, call me paranoid.

The only thing i can think of right now is i hit a pothole a good while ago and i am just witnessing its after effects right now, but it seems odd that it miraculously deflated in such a small amount of time when it seemed perfectly fine previously.

Since last year i always do a quick visual inspection of my tyres before i get in (before ill admit i did it seldom enough). this seems to have come out of nowhere. I'm lucky both times that it was parked when i noticed it

Have you ruled out the possibility that you have picked up a slow puncture today. If a tire place can't find a puncture ask them to put plenty of bead seal on it.

mickdw

It could be a tiny defect that only allows air to escape when the tyre is rotated to a specific position while parked
I would have the the area of the rim where the tyre is seated checked for imperfections.
This is not something I would live with. If I could get no explaination as for the pressure loss, it would mean new rim & tyre for me.

Abelloid

Yeah, I had the same problem a long time ago and was giving my neighbours the evil eye. Get the tyre removed and the inner rim/bead cleaned.

Owen

Completely extreme step, but it does work occassionally, have the air in your tires replaced by Nitrogen. I had it done with the work car, I was loosing 10 PSI a week with the weight of the car, got a friend with a trucking company to replace the air with Nitrogen, and it's slowed all the losses right down.

Damien360

PaintDoctor wrote: »

Completely extreme step, but it does work occassionally, have the air in your tires replaced by Nitrogen. I had it done with the work car, I was loosing 10 PSI a week with the weight of the car, got a friend with a trucking company to replace the air with Nitrogen, and it's slowed all the losses right down.

Given that the air you breathe has 78% content of Nitrogen, I fail to see how it will work. Advance Pit Stop have a Nitrogen generator in their unit near Kylemore road. It is no more than an air compressor without the required equipment to purify the nitrogen (they had the unit open and I got a look. Our company sells and services N2 generators for labs). It is a gimmick to justify charging you silly money for the air they put it.

I wonder has the OP got tyres that fit his rims correctly (the stretched wall look going towards the inside of the tyre). When he parks up at an angle (of a footpath), is the tyre shape changing enough to allow a leak ?

Owen

Damien360 wrote: »

Given that the air you breathe has 78% content of Nitrogen, I fail to see how it will work. Advance Pit Stop have a Nitrogen generator in their unit near Kylemore road. It is no more than an air compressor without the required equipment to purify the nitrogen (they had the unit open and I got a look. Our company sells and services N2 generators for labs). It is a gimmick to justify charging you silly money for the air they put it.

Odd then that transport/haulage companies rave about it then, and odder still that my tires deflate less now that there's Nitrogen in them.

slimjimmc

PaintDoctor wrote: »

Completely extreme step, but it does work occassionally, have the air in your tires replaced by Nitrogen. I had it done with the work car, I was loosing 10 PSI a week with the weight of the car, got a friend with a trucking company to replace the air with Nitrogen, and it's slowed all the losses right down.

I thought the reasoning behind nitrogen is that it doesn't expand and contract as much air and therefore gives more stable driving. Also you don't get as much fluction in tyre pressure (rising on hot days and falling on cold days) due to weather. I find it hard to believe it doesn't leak just as easily as air.

slade_x

mickdw wrote: »

it would mean new rim & tyre for me.

I would love to replace the whole wheel to be done with it but sourcing the single wheel may be a problem as i have been told, buying a whole new set is the easiest way out of it, which i do not want to do, as all the others are perfect

This is it (taken in the dark with an xperia x1):


Uploaded with ImageShack.us


Uploaded with ImageShack.us

The nearest i can match are these:
http://www.ozracing.co.uk/superleggera_race_silver.htm

I am pretty sure these are them, could anyone point to a brand new source for these locally (south of ireland) or even online (preferable as my driving ability seems limited at present :mad:) Thanks

muckwarrior

Are you sure someone didn't just let your tyre down?

Damien360

PaintDoctor wrote: »

Odd then that transport/haulage companies rave about it then, and odder still that my tires deflate less now that there's Nitrogen in them.

slimjimmc wrote: »

I thought the reasoning behind nitrogen is that it doesn't expand and contract as much air and therefore gives more stable driving. Also you don't get as much fluction in tyre pressure (rising on hot days and falling on cold days) due to weather. I find it hard to believe it doesn't leak just as easily as air.

Makes no sense to me at all but here is a piece found with google. Seems there may be truth in it but i am very sceptical.

http://lifestyle.iloveindia.com/lounge/nitrogen-gas-to-inflate-car-tyres-3606.html

and the counter argument

http://www.racq.com.au/motoring/cars/car_advice/car_fact_sheets/nitrogen_for_tyres

RandomAccess

Perhaps try partially inflating it, and check if it maintains the pressure.

I would guess that there may be a split somewhere which only opens when the tyre is in a particular position or pressure declines to a specific level.

Thats just a theory mind, but its worth a shot if you don't have any better ideas.

slade_x

muckwarrior wrote: »

Are you sure someone didn't just let your tyre down?

yes it was parked in my back yard, no one has any reason to do so also.

slimjimmc wrote: »

I thought the reasoning behind nitrogen is that it doesn't expand and contract as much air and therefore gives more stable driving. Also you don't get as much fluction in tyre pressure (rising on hot days and falling on cold days) due to weather. I find it hard to believe it doesn't leak just as easily as air.

That has to be the primary reason but nitrogen does have a larger covalent radius than oxygen which makes up about 1/4 of the air in your tyre.

Another claim i have heard of is less net corrosion. however if you have a car and your tyres (and rims) are corroding naturally before they wear on the road you really really really dont need a car if you can afford to have it parked up for decades. also theres not much you can do about the corrosive nature of our atmosphere outside the tyre. you may notice less or no corrosion on the inner rim of the wheel, which i think weve all seen if you have ever been present for a tyre change, but over the average short life of an actual tyre from road wear i wouldnt think it wouldn't be worth mentioning

Oh and i never park on a curb or curb it

Have you gone to a puncture repair place yet ? Looney thread until you do and they confirm it is not losing air (or otherwise)

dak

Maybe you have a faulty air valve .. happen to me once! Changed it and problem fixed !

Viper_JB

dak wrote: »

Maybe you have a faulty air valve .. happen to me once! Changed it and problem fixed !

Think it may be worth checking especially if your tyre fully deflated after having the valve replaced, could be as simple as a botched job on it.

Viper_JB

Viper_JB wrote: »

Think it may be worth checking especially if your tyre fully deflated after having the valve replaced, could be as simple as a botched job on it.

the new valve was a year ago
It has now deflated after holding air for a year from what I can gather.

slade_x

RoverJames wrote: »

the new valve was a year ago
It has now deflated after holding air for a year from what I can gather.

Thats correct

Had it checked about 3 hours ago

It was filled to 30 psi last night and was still reading 30 on a gauge when it was looked at

Esel

Ssssssssssssnake of a neighbour?

tmcw

Could be that your tyres look the same (to you) from, for example, 30psi down to 20psi. It may take a long time for your tyres to go from 30 to 20 psi, so unless you're checking your car tyre pressures weekly (which maybe you should be doing, depending on your milage), then the tyres may always look the same, until the pressure goes below a certain amount which then becomes very noticable.

I remember once checking my own tyres, and being a bit surprised that one of them was 28psi, and another, which didn't look deflated or any different to the other, was closer to 20psi.

Like a lot of things in life, unless a change is dramatic, variations can be very difficult to spot, unless closely monitored.

skywalker_208

Its probably a new slow puncture where the hole is only open when the car is in a certain position i.e. the weight of the car is in a certain position to allow the hole to open enough to let air out.

Get a bucket of warm water and stick a good dash of fairy liquid in it.
Throw some over the tyre - leave for a couple minutes.
Inspect to see if there are any bubbles gathering.
If not - drive car forware a bit and do the same until you do find something

Bing_IRL

You could just put an inner tube in it? Is this still done?

skywalker_208

Bing_IRL wrote: »

You could just put an inner tube in it? Is this still done?

Yes it is but depends on the size of the tyre.
e.g. you could put one in a 155/80/13 size tyre but you cannot put one in a low profile tyre.
This is only for steel wheels though - not for alloys.