[F30AM]

This is just a Friday rant.

I had not checked my pressures for 3 months!

I know with my 18" wheels and mixed tyres: Front 2.4 bar (34.81 psi), Rear 2.6 bar (37.71 psi).

The car drove and rode like a dream until I asked BMW to check tyre pressures whilst it was in yesterday for a quality enhancement. Now I have a slightly unsettled ride but much more steering feel. I had made it clear to BMW that Front 2.4 bar, Rear 2.6 bar.

I am quite sensitive to ride comfort.

I will now have to go to Auto Audio tomorrow morning, wait for 2 hours for the tyres to cool down before re-checking the pressures.

What a pain.

Feel much better now and thanks for listening.

[mproudfoot]

I hate to admit this but I hadn't checked my tyre pressures since receiving the car back in October, until this morning when I popped into a local tyre place to replace the air with nitrogen (I didn't know if that would be possible in run flats). Since then, the steering feels much lighter, but I haven't noticed any appreciable difference in ride comfort or road noise. I was kind of hoping the latter would improve but I guess it's just the way these tyres are (Potenzas on the 18" 400s).

Hope you get it back to a state that suits you.

[F30AM]

Originally Posted by mproudfoot

I hate to admit this but I hadn't checked my tyre pressures since receiving the car back in October, until this morning when I popped into a local tyre place to replace the air with nitrogen (I didn't know if that would be possible in run flats). Since then, the steering feels much lighter, but I haven't noticed any appreciable difference in ride comfort or road noise. I was kind of hoping the latter would improve but I guess it's just the way these tyres are (Potenzas on the 18" 400s).

Hope you get it back to a state that suits you.

Thanks for giving me the idea of Nitrogen.
Will go to Kwik Fit tomorrow to put this gas in. It will cost me £5!

[alex_chung]

I have not checked mine since I picked up the car last week but will check tomorrow when I wash the car.
Alex

[deeno]

My current E90 lci on 18's and non run flats is quite sensitive to tyre pressure. Set to the recommended levels the ride feels quite firm and a little fidgety, picking up every imperfection in the road.

However drop the pressure down a tiny bit and the ride is really smooth. Still crashy over really bad roads but settled on good roads. Don't notice any drop off in mpg either. Will have to experiment with my 330d when it arrives in a week or so to see the optimum pressures for 19's on 403's.

[F30AM]

Originally Posted by deeno

My current E90 lci on 18's and non run flats is quite sensitive to tyre pressure. Set to the recommended levels the ride feels quite firm and a little fidgety, picking up every imperfection in the road.

However drop the pressure down a tiny bit and the ride is really smooth. Still crashy over really bad roads but settled on good roads. Don't notice any drop off in mpg either. Will have to experiment with my 330d when it arrives in a week or so to see the optimum pressures for 19's on 403's.

I have a feeling that the BMW's tyre pressure gauge was not properly calibrated.
And yes, very sensitive to tiny changes in pressure,

[Rich9600]

I'd go for a DIY inflation solution. I have one of these. No issue of cooling tyres... Easy check before a longer run etc.

http://www.amazon.co.uk/Ring-Automot...air+compressor

It seems accurate against other gauges and is very easy to use. Auto shut off at your programmed pressure and 12V power from your car. Also, very quick for winter use...

403M's at the recommended 2.6 Bar all round and all is well. The car came at 2.8 Bar...

[chiark]

Easy solution to monitoring tyre pressures? Buy a new car - TPMS now built in
/smug mode.

[F30AM]

Originally Posted by Rich9600

I'd go for a DIY inflation solution. I have one of these. No issue of cooling tyres... Easy check before a longer run etc.

http://www.amazon.co.uk/Ring-Automot...air+compressor" rel="" target="_blank">http://<a href="http://www.amazon.co...compressor</a>

It seems accurate against other gauges and is very easy to use. Auto shut off at your programmed pressure and 12V power from your car. Also, very quick for winter use...

403M's at the recommended 2.6 Bar all round and all is well. The car came at 2.8 Bar...

The link now works!
http://www.amazon.co.uk/Ring-Automot...air+compressor

[F30AM]

Originally Posted by chiark

Easy solution to monitoring tyre pressures? Buy a new car - TPMS now built in
/smug mode.

They set my TPMS yesterday at BMW.

[Rich9600]

Originally Posted by F30AM

The link now works!
http://www.amazon.co.uk/Ring-Automot...air+compressor

iPad playing silly buggers. Fixed the original.

[Alkidrew]

Originally Posted by F30AM

They set my TPMS yesterday at BMW.

I might be wrong but I think chiark is alluding to the fact that new cars have real tpms in them to measure pressure whereas earlier cars use wheel speed to detect pressure drop. I.e. When it's flat it won't turn the same rpm as an inflated tyre.

Like I say, I might be misunderstanding and don't know if tpms is any better.

[F30AM]

Quick question: If they completely deflate a Runflat tyre whilst still loaded by the car, will it damage the tyre?

[Alkidrew]

Originally Posted by F30AM

Quick question: If they completely deflate a Runflat tyre whilst still loaded by the car, will it damage the tyre?

No, the tyre walls are built to support it, even moving but not too fast and not too long. The longer you do this, the more it will weaken. I drove 90 miles on the motorway with zero pressure once but kept it below 50.

Just deflating the tyre with the weight of the car is fine, it's the bare minimum you'd expect.

[Rich9600]

Originally Posted by F30AM

Quick question: If they completely deflate a Runflat tyre whilst still loaded by the car, will it damage the tyre?

I got a puncture late at night 120 odd miles from home. I slowed to 50mph but eventually was up to almost normal speed! It was 11pm and I had to be up at 5am...

Then I drove to work the next morning and back. Then to the tyre centre.

So, 150 miles on a flat. They said they could plug it... The walls were still ok...

E90 on 225/45/R17 Continentals then.

[Torquein]

Originally Posted by Rich9600

I'd go for a DIY inflation solution. I have one of these. No issue of cooling tyres... Easy check before a longer run etc.

http://www.amazon.co.uk/Ring-Automot...air+compressor

It seems accurate against other gauges and is very easy to use. Auto shut off at your programmed pressure and 12V power from your car. Also, very quick for winter use...

403M's at the recommended 2.6 Bar all round and all is well. The car came at 2.8 Bar...

I have a similar one I got from halfords, works great!

[F30AM]

Originally Posted by JM7789

I have a similar one I got from halfords, works great!

Unfortunately, does not pump Nitrogen!
Must try this gas just for the hell of it. It would be gas, don't you think?

[Rich9600]

Originally Posted by F30AM

Unfortunately, does not pump Nitrogen!
Must try this gas just for the hell of it. It would be gas, don't you think?

We need comedy sound effects...

[Torquein]

Originally Posted by F30AM

Unfortunately, does not pump Nitrogen!
Must try this gas just for the hell of it. It would be gas, don't you think?

It technically pumps about 78% nitrogen.

[....,,,,..,,..]

What is the reasoning behind putting nitrogen in tyres?

[Torquein]

Originally Posted by Brigand

What is the reasoning behind putting nitrogen in tyres?

http://www.theaa.com/motoring_advice...-nitrogen.html

To waste money according to the aa

[F30AM]

Originally Posted by Brigand

What is the reasoning behind putting nitrogen in tyres?

No point really, but why not?
Read this:
http://www.theaa.com/motoring_advice...-nitrogen.html
and this:
http://www.racq.com.au/motoring/cars...ogen_for_tyres