car tyre wont inflate.

teednab-el

Ok guys I was inflating my tyres today, and topped up my front tyres to 32 psi from 30.5 psi approx. Then went and did the back tyres. The rear left tyre was fine and left it at 30 psi. The right tyre however was at 24 psi so I tried inflating it and the needle on the air compressor dial did not stir. It stayed at or even dropped slightly below 24psi. I tried it again but still no joy.

So I went to a different service station and tried the tyre again with a different air compressor and still couldn't inflate the tyre, the needle on the compressor dial dropped slightly again and is now at 22 psi. I might just put the spare wheel on in replace of this tyre for safety. I cleaned the valve of any dirt or grit that might stop it from inflating but with no luck.


What is the problem here? Anything else I can do? Those air compressors I used are accurate.

Btw the car is an Audi A4 with 16' alloys.

Damokc

This sounds like trolling!! haha!! you have a slow puncture I would imagine!

Mycroft H

teednab-el wrote: »

Ok guys I was inflating my tyres today, and topped up my front tyres to 32 psi from 30.5 psi approx. Then went and did the back tyres. The rear left tyre was fine and left it at 30 psi. The right tyre however was at 24 psi so I tried inflating it and the needle on the air compressor dial did not stir. It stayed at or even dropped slightly below 24psi. I tried it again but still no joy.

So I went to a different service station and tried the tyre again with a different air compressor and still couldn't inflate the tyre, the needle on the compressor dial dropped slightly again and is now at 22 psi. I might just put the spare wheel on in replace of this tyre for safety. I cleaned the valve of any dirt or grit that might stop it from inflating but with no luck.


What is the problem here? Anything else I can do? Those air compressors I used are accurate.

Btw the car is an Audi A4 with 16' alloys.

It's a puncture m'dear.

I have often encountered that, for whatever reason the pumps seem to be incredibly sh1t at some stations. One day at the local Maxol a chap was trying to inflate a nearly flat tyre on his car, pump wouldn't inflate it at all. It had not bother topping up his other tyres. I had a slow puncture, 20psi in the tyre, wouldn't inflate. No bother at a garage up the road, I can't offer any reason why though.

I would think if the weight of the car wasn't on the tyre it might inflate, that's just a thought though, worth trying though if you are thinking of throwing on the spare as you'll have to jack it anyway.

Damokc

Damokc wrote: »

This sounds like trolling!! haha!! you have a slow puncture I would imagine!

BX 19 wrote: »

It's a puncture m'dear.

That doesn't explain why the pump won't inflate it, if the thing is holding 22/24psi it should pump to higher for a while at least before losing the pressure again.

working fool

Some garage pumps have a maximum pressure setting on the main unit
Maybe someone before you was inflating a bicycle tyre before you ?

teednab-el

BX 19 wrote: »

teednab-el wrote: »

Ok guys I was inflating my tyres today, and topped up my front tyres to 32 psi from 30.5 psi approx. Then went and did the back tyres. The rear left tyre was fine and left it at 30 psi. The right tyre however was at 24 psi so I tried inflating it and the needle on the air compressor dial did not stir. It stayed at or even dropped slightly below 24psi. I tried it again but still no joy.

So I went to a different service station and tried the tyre again with a different air compressor and still couldn't inflate the tyre, the needle on the compressor dial dropped slightly again and is now at 22 psi. I might just put the spare wheel on in replace of this tyre for safety. I cleaned the valve of any dirt or grit that might stop it from inflating but with no luck.


What is the problem here? Anything else I can do? Those air compressors I used are accurate.

Btw the car is an Audi A4 with 16' alloys.

It's a puncture m'dear.

Even so it should inflate I would have thought?

teednab-el

teednab-el wrote: »

Even so it should inflate I would have thought?

Unless there was an appreciable hole in it
The compressors are crap, jack it up to get the weight off it and I reckon it will inflate.

teednab-el

working fool wrote: »

Some garage pumps have a maximum pressure setting on the main unit
Maybe someone before you was inflating a bicycle tyre before you ?

On the first service station I inflated the other three tyres before doing this tyre.

mickdw

I'd suggest that the fitting is not going onto the valve correctly on that wheel. Can you easily let air out by pressing the valve in by hand?
Is there any damage to the valve?

Indricotherium

working fool wrote: »

Some garage pumps have a maximum pressure setting on the main unit
Maybe someone before you was inflating a bicycle tyre before you ?

It'd be a rare bicycle tyre that only wanted 22 psi.

kneemos

Indricotherium wrote: »

It'd be a rare bicycle tyre that only wanted 22 psi.

Mountain bike tyres inflate to 65psi.

Nissan doctor

Faulty valve I'd be almost certain.

CiniO

kneemos wrote: »

Mountain bike tyres inflate to 65psi.

But you don't want 65psi for mountain biking. For road - yes, but for offroad 22 could be about perfect.

teednab-el

mickdw wrote: »

I'd suggest that the fitting is not going onto the valve correctly on that wheel. Can you easily let air out by pressing the valve in by hand?
Is there any damage to the valve?

The valve looks ok and fits ok from what I can see.

Jimbob 83

Pump harder

Nissan doctor

teednab-el wrote: »

The valve looks ok and fits ok from what I can see.

The internal part of the valve is likely damaged or seized so its not allowing the air past.

Bruthal

RoverJames wrote: »

Unless there was an appreciable hole in it
The compressors are crap, jack it up to get the weight off it and I reckon it will inflate.

It shouldnt make any difference if the weight of the car is on it or not i wouldnt think. 30psi is 30psi. It must be a problem valve.

robbie7730

robbie7730 wrote: »

It shouldnt make any difference if the weight of the car is on it or not i wouldnt think. 30psi is 30psi. It must be a problem valve.

It's remotely interesting
30psi is no doubt 30psi as you say.

The pressure will increase slightly with the load of a car on it, I do mean slightly.

If you applied a huge force to an inflated tyre you could squeeze in the tyre, deforming it, the pressure will rise in there, the same happens when the car's weight is on it to a smaller degree. The variance in pressure would be smaller than the variance in the pressure gauge though.

If you were inflating a rear tyre with a foot pump, given the choice would you like to inflate it with no one sitting in the car or with 3 huge fat bastads sitting in the back seat and two more sitting on the boot lid?

I'd be 90% certain it's two sh1t compressors rather than a faulty valve.

Bruthal

RoverJames wrote: »

If you were inflating a rear tyre with a foot pump, given the choice would you like to inflate it with no one sitting in the car or with 3 huge fat bastads sitting in the back seat and two more sitting on the boot lid?

It would still take the same amount of effort to get the tyre to 30psi i would of thought. The difference is the contact patch would be larger, probably meaning marginally less air is needed, which also means the pressure might marginally reduce when the fat lads get out:D

robbie7730

robbie7730 wrote: »

It would still take the same amount of effort to get the tyre to 30psi i would of thought. ........

I dunno, as I said both myself and another lad encountered the local Maxol's pump as refusing to inflate two low psi tyres, the next garage I tried the pump did the trick. I was sort of pondering it briefly back then and again today since this thread came along.

What about inflating a bicyle tyre with a handpump with and without someone sitting on the bike, you'd defo find it easier without the weight of the person in it

Sure if weight (or load) has no effect loads of hydraulic systems could be pneumatic.

stoneill

If you could inflate three tyres no problem then one tyre had an issue then I would suggest there is a problem with your tyre, not the compressor.
Did you check the valve on the tyre to make sure that it is not damaged, dirt caught etc.

Bruthal

RoverJames wrote: »

I dunno, as I said both myself and another lad encountered the local Maxol's pump as refusing to inflate two low psi tyres, the next garage I tried the pump did the trick. I was sort of pondering it briefly back then and again today since this thread came along.

There is no doubt it could be problem pumps alright.

What about inflating a bicyle tyre with a handpump with and without someone sitting on the bike, you'd defo find it easier without the weight of the person in it

To get a bicycle tyre to 90psi for example, would be the same effort even if there was a ton weight on it. But when the weight is taken off, the pressure will drop a little. And now will need to be topped back up to 90psi.

With weight now applied, whatever pressure the 90psi tyre now goes up to, is the pressure that would be needed to be pumped into the flat tyre with the person on it, so it would require slightly more effort alright. But to just reach the 90psi with the person on it, would be the same as reaching 90 psi with no one on it. But it would be slightly under inflated at 90psi with a person on it.

But to get the OP car tyre to 30 psi, would be independent of what weight was on the tyre. It wont stop at 24psi because there was weight on it.

If the pump has an actual pressure limit switch at 30psi, it will still reach this 30 psi even if the tyre had the weight of a jumbo jet on it.

Sure if weight (or load) has no effect loads of hydraulic systems could be pneumatic.

Its not really the same thing, pumping a certain volume to a given pressure takes a certain amount of work. A tyre with a load on it will reach the 30psi with slightly less air. So with no load on it, it takes marginally more air to reach 30psi.

Hydraulic system pressures change enormously depending on loads, but the volume remains constant. Air would turn to liquid under them pressures, and the volume would drop to hundreds of times less, so couldnt work, besides the fact the hydraulic pumps couldnt pump air. Hydraulics are just a type of leverage system.

Bruthal

RoverJames wrote: »

It's remotely interesting
If you applied a huge force to an inflated tyre you could squeeze in the tyre, deforming it, the pressure will rise in there, the same happens when the car's weight is on it to a smaller degree. The variance in pressure would be smaller than the variance in the pressure gauge though.

Yea thats very true alright. To see the differences wouldnt be possible with the resolution a standard gauge would have.

..... what about a balloon ? Same effort to inflate it with and without an elephant sitting on it ? It's exactly the same principle is the tyre with and without the weight of the car on it, scaled up obviously. It cant take the same effort as you're shifting a mass as well as inflating.

teednab-el

stoneill wrote: »

If you could inflate three tyres no problem then one tyre had an issue then I would suggest there is a problem with your tyre, not the compressor.
Did you check the valve on the tyre to make sure that it is not damaged, dirt caught etc.

I checked valve for dirt and grit that might be lodged near the valve but didn't spot anything that could prevent me from inflating it. Valve looked ok but I couldn't tell if it was faulty or not. Its not caught on position but i havent experienced this before. The two pumps I use I use them on a regular basis and they are accurate as I have a air compression device for measuring psi.

Bruthal

RoverJames wrote: »

..... what about a balloon ? Same effort to inflate it with and without an elephant sitting on it ? It's exactly the same principle is the tyre with and without the weight of the car on it, scaled up obviously. It cant take the same effort as you're shifting a mass as well as inflating.

But we are not talking about inflating it to the same volume with the elephant sitting on it, only the same pressure.

So if a fully inflated baloon takes 2 litres of air and reaches 3 psi, if an elephant sits on it before you inflate it, it will now take almost no air, but you can still easily blow it to the same pressure. Easier in fact, as now very little air is needed to reach the 3 psi. But it will be under inflated when he gets off it.

So to get air into the elephant squashed balloon to yield a 30psi pressure would take the same effort as getting 30psi into the unloaded balloon? I'm struggling with that to be honest

JUst saw your edit

Bruthal

RoverJames wrote: »

So to get air into the elephant squashed balloon to yield a 30psi pressure would take the same effort as getting 30psi into the unloaded balloon? I'm struggling with that to be honest

Yea there is absolutely no doubt about it. Your thinking of the baloon lifting the elephant. It wont, but 30 psi can still be pumped in. There will just be little or no increase in volume.

If you go back to the car tyre. A mechanical pump pumps it to 30 psi. If the tyre was made of steel that cant expand, it will still be easy for the pump to pump it to 30 psi.

Bruthal

RoverJames wrote: »

JUst saw your edit

Is that good or bad:)

Dunno :pac: still think jacking it and using the same pump might work.

Bruthal

RoverJames wrote: »

Dunno :pac: still think jacking it and using the same pump might work.

Well if the pump wont pump the tyre beyond 24psi, how would taking the weight of the car off it now allow it to reach 30psi?

After all, all the pump senses is 24psi from the tyre valve.

Even if there was a 20 ton car on the tyre, the pump should still pump the pressure in the tyre to 30psi as easily as if it was a spare wheel with no load on it. It just wouldnt lift the 20 ton load up very much, if at all, so the tyre would remain like a flat.

This is assuming a properly working pump that is able to inflate to 30 psi.

Dunno, I don't think the pumps the OP used are working properly though.

Bruthal

RoverJames wrote: »

Dunno, I don't think the pumps the OP used are working properly though.

Possibly. Its either that, or the tyre valve. Dont think i seen a valve do that, but had pumps that wouldnt pump the tyre up to pressure myself alright.

Just in the OP`s case, it seemed to pump his other tyres up ok.

2 stroke

I would say bs but I had a similar experience last week. Compressor at petrol station would inflate every tyre except the one with a slow leak. I went up the road to tyre shop and no problem inflating it there, guy could make no sense of it except he said I wasnt the first to have the same problem recently. I wonder is there a faulty batch of forecourt gauges. The weight of the car on the tyre is irrevelant unless compressors have developed intelligience, and 30psi would pop a baloon.

2 stroke

2 stroke wrote: »

I would say bs but I had a similar experience last week. Compressor at petrol station would inflate every tyre except the one with a slow leak. I went up the road to tyre shop :............ and 30psi would pop a baloon.

the balloon was a hypothetical example, the experience you had is similar to mine.

Bruthal

If you take a car tyre as having 1000 square inches( just as example), and inflate the spare to 30psi.

Now put 1000 pounds weight on the tyre by putting it on a 4000 pound car (assuming equal load on each wheel which it wouldnt be). Its pressure will now go to 31 psi.

If you however put the flat tyre on the car, and pump to 30 psi, removing the wheel will drop the pressure to 29 psi. So as said earlier, it will be inflated slightly less when pumped to 30psi with the weight on it, than when pumped unloaded. It is still reaching 30 psi, but slightly quicker. (With the weight of the car on it, there is slightly less volume to fill to reach the same pressure)

So Pumping the tyre while on the car would need 31 psi so that its 30 psi when removed. Or to pump the spare so it was 30psi when then fitted to the car would only need 29psi.

As you said, these differences wouldnt be seen on a forecourt pump gauge.

So the pump not going beyond 24psi is possibly the pump alright, if not the wheel valve. Maybe the gauge sticking, although the user should still hear the air going in.

toe2toe

check to see i there is a collar type of thing slid over the tyre valve ,sometimes used to match alloys? they can restrict the connector on compressor pushing down enough on valve if there is one it can be slid off