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Discussion Starter · #1 ·
I drive a manual 97' 9000 2.0 Ecopower Anniversary . I checked my tyre pressures and set it to 30 psi on Monday. My everyday mileage is something like 3-5 miles on an average. On Wednesday I drove 125 miles mainly through hills and country roads. And yesterday something told me that the tyre pressure had falled. So I checked and it had fallen to 27 and I got it back to 30 again. Is this normal? I do not know because this was my longest drive with this car. I do not know how to know by the feel of the drive for fallen tyre pressure. Would be thankful for any advice.

TIA,
Neel.
 

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Make sure you check the tyre pressures when cold. The pressures will normally read higher when warm after a long journey.

I had the same problem on one of my front tyres recently. And I've had the same problem on almost every car I've owned. It sems to happen as the tyres are getting on a bit. Has the tyre been on there long?

Without relacing the tyre unneccessarily, you could take it to some where like kwik-fit and have them take the tyre off and re fit it.

You could also have the tyre filled with nitrogen. This helps stabilise the pressures.
 

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Neel,

Welcome to Saabscene.

As Toby says check your pressures when cold. Even one mile of driving will increase the pressure a measurable amount even if it's at low speed.

Did all your pressures fall to 27 psi, if so it's definatly a temperature related issue. If just one tyre then a puncture or valve problem.

HTH.

Nick.
 

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Discussion Starter · #4 ·
Thanks Toby Field.

Actually I did not check the tyre pressure on the same day after the long drive. I checked it on the next day after a one mile drive to the filling station (that is where I usually check).

I have owned the car for about 5 months now and it has done less than 2000 miles since. I am not sure how long the tyres have been there. The back tyres look fairly new-ish. They are both Vredestein sportrac. The front two tyres are a p6000 and an eaglestar. The do not look as new.

Who would do the nitrogen filling? is it any garage or are there special places to do it?

Any clues on how much a re-fit at kwik fit might cost?

Thanks,
Neel.
 

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Discussion Starter · #5 ·
Thanks Nick.

Actually I drove it to the local Tesco filling station and set the air machine to 30 and held the pipe to all the tyres. It showed 27 on all of them and took a few seconds till it beeped at 30. So yes, all the tyre pressures had fallen to 27.
BTW, is there any easy way to understand that the tyre pressure might have fallen while driving? I am sorry if I sound very stupid
. I am driving for only as long I have owned my 9000 and am very new to motoring and cars.

It feels great to see two replies within 15 mins of my post. This really is a great place.
 

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Garage tyre gauges are, unfortunately, quite often inaccurate. To determine whether you have got a problem, it's worth investing in a cheap digital tyre pressure gauge (less than a tenner from many outlets). Measure the pressues of all tyres and note how they change relative to one another. A good time to do this might well be an hour or so after you get in, as long as none of them have been in direct sun.

Just out of interest, what was it that led you to believe your trye pressures had dropped? 30 to 27psi is not a terribly significant change.

Nitrogen is good for maintaining the same pressure as conventional air has water vapour in it, which can seep through the tyres, resulting in a loss of pressure.
 

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Discussion Starter · #8 ·
Nick,

I took the 30 psi reading on Monday evening after a mile's town driving to get to the Tesco (while returning home from work). And then drove the usual 5 miles on Tuesday. On Wednesday I had a long drive of 125 miles and I checked the pressure after a one mile drive on Thursday. All the tyres showed 27 psi and I got it up to 30 psi again.

Mark,

I will certainly invest in a digital pressure guage. The Tesco tyre pressure guage in Haverfordest is actually a digital one and not the normal meter kinds.

Nice question about how I knew if tyre pressure was right. I don't know if what I felt was right. But I had a nagging feeling that the car was not handling as well as it normally does. I am not even sure if that was right as you can imagine I am not experienced. Maybe it was just a hunch.

Thanks to you all for helping so much. I do appreciate this.

Thanks,
Neel.
 

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Even if the gauge is accurate, you could get those pressure variations just by going on a day that's warmer or colder or with a different air pressure in the atmosphere due to weather systems. Atmospheric pressure in the UK can vary by around 1 to 1.5 lb/sq in depending on whether its a low pressure area passing over or an anti-cyclone.
 

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Regardless of any pressure difference, you are going to get slight handling differences with different makes of tyres on the front axles.

Possibly major handling differences in an emergency


I'd put the Vredesteins on the front and the other two on the rear. It won't cure the pressure problem but should make it safer and better to drive.
 

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Discussion Starter · #11 ·
I can see that the Vredesteins put on front will make a difference in the handling and they are newer tyres as well. I am considering getting that done soon.
The car is going in for MOT this afternoon. Have made most of the checks that I could do easily yesterday. Hopefull it should sail through. The guy who is going to do it saw it last week and said that everything seems alright. Will let you know how it goes.

Thanks a ton for all the helpful replies.
 
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