3psi Discrepency at different air lines.

[ringway]

I checked my tyre pressures this evening.

Last week I checked/inflated at Tesco and for simplicity I'll use a figure of 31psi.

Tonight at a Total station the tyres had a reading of 27/8, so I inflated to 31.

It became obvious that I had too much pressure in the tyres (hated the hard ride) so at a BP petrol station 20 miles away I checked the tyres and had to deflate from 34psi to 31psi.

The tyre temperature was consistent each time I used the air lines.


Surely all air lines are calibrated in the same way (or they should be)?


If you have original spec tyres and wheels you can check for the correct pressures on this site.

 

[Sp!ke]

What temperatures were your tyres at the time?

On top of the above, forecourt air lines are notoriously inacurate. Buy something that you can rely on instead.

http://www.autoexpress.co.uk/products/products/66830/tyre_pressure_gauges.html

 

[ringway]

What temperatures were your tyres at the time?

On top of the above, forecourt air lines are notoriously inacurate. Buy something that you can rely on instead.

Tyre pressure gauges | Products | Auto Express

Looks like I'll be getting a Race X Professional Tyre Gauge then at £8.99.

Cheers

Paul.

 

[johnsco]

Forecourt gauges are pretty hopeless in my experience.
The hand-held ones get knocked about, and have a hard life.
The ones that tick away and then bleep at you ... I never seem to get the same result twice.

I always use my own gauge, which I keep in the glove compartment.

Cheers.
Johnsco

 

[timskemp]

Or get your own inflator

I've got one of these, seems to be very consistent and of course can actually be used before moving the car.

 

[BTB 500]

As above, I would never rely on a forecourt gauge (I also have that one that was the Auto Express best buy).

Apart from anything else, pressures are meant to be set with cold tyres. So you can only do it accurately at home - as soon as you drive anywhere the tyres warm up.

 

[Dieselman]

Looks like I'll be getting a Race X Professional Tyre Gauge then at £8.99.

Cheers

Paul.

I've got one of those and it seems pretty good, but the cheapy pencil type I have also seems just as accurate.
People slate pencil ones but I don't see how they can be wrong (if they are made right). They rely one air pressure outside the piston compared to inside it, how can that vary.? (I appreciate some are spring loaded which will vary)

 

[lynall]

Pcl tyre equip very good.

Have used them for years, also pretty robust just broke my pencil one (up to 150psi!) at work have been using it non stop for 5 or 6 years.


Lynall

 

[robert.saunders]

If you have original spec tyres and wheels you can check for the correct pressures on this site.

I entered my reg on that site and it stated:

225/40R18 W 92

F 2.2 BAR / 32 PSI
R 2.1 BAR / 31 PSI

Yet the sticker on my fuel flap states 36 front and 33 rear (I have standard Ford 18" alloys)

 

[welland99]

It became obvious that I had too much pressure in the tyres (hated the hard ride) so at a BP petrol station 20 miles away I checked the tyres and had to deflate from 34psi to 31psi.

I'm surprised you could detect a difference in the ride for a 3 psi reduction. I think the difference in pressure caused by temperature would be greater than 3 psi, which means that you must either be unhappy with cold or hot tyres.

 

[ringway]

I'm surprised you could detect a difference in the ride for a 3 psi reduction. I think the difference in pressure caused by temperature would be greater than 3 psi, which means that you must either be unhappy with cold or hot tyres.

I could notice the difference, that is why I took the trouble to re-check and deflate. Handling was improved but I didn't enjoy the hard ride.

 

[lynall]

I have noticed small differences in ride quality before and it was tyre pressures.
Much more noticable with low profiles.




Lynall