1992 1.4i GLS tyre pressures

[warwound]

Hi all.

Got myself a 1992 Astra 1.4i GLS a few weeks back and decided yesterday to check my tyre pressures at the local garage.

Had previously consulted the Vauxhall Drivers Manual and it recommended the following pressures for my 175/65/R14 82H tyres:

Normal load: 27 front, 23 rear.

Full load: 30 front, 33 rear.

Thinking that some air would be needed i was surprised to find my tyre pressures to be 32 front and 36 rear...

My plan was to use the normal load recommended pressures.
So rather than mess about i left them at their over-inflated(?) pressures.

What's everyone think/recommend?

A lot of my driving is with just me in the car, other times one or two passengers but seldom anything approaching full load.
I occasionally break the 60mph speed limit but usually drive conservatively - mpg being more important to me than mph!

Should i go for the 27 front, 23 rear?
I had a search of the forum but found nothing related to my tyre size.

Thanks.

Martin.

 

[srb]

id just leave em as they are they will creep down to the recommended, then maybe just keep them half way between 'normal' and 'fully loaded'. the tyres on my 1.4 are 155/80/13s and the recommended pressures are more or less the same as urs for fully loaded, but higher for normal - i just make sure they are never below the 'normal' level and are closer to fully loaded

 

[urbanvibrati]

I think you get better MPG if you have all the tires full. Maybe someone knows more about this?

 

[warwound]

Thanks for the replies.

Halfway between the recommended pressures for normal and full load seems the best option.

urbanvibrati what do you mean by 'tires full'?

Better MPG with higher pressures maybe?

Martin.

 

[Lefthooker]

Tyres that are a few PSi overinflated (thats what urbanvibrati means by "full") have less roll friction then with the recomended pressure. You have to remember that the car manufacturers are not really worried about your milage costs, but your saftey. The recomended tyre pressures are such that the tyres, due to thier size and grip pattern, are set to give maximum grip on the road. Increasing the preassure will "raise" the tyres slightly off the road giving it less rolling friction, therefor using less energy to move = saving petrol.
It must be noted here, tyres with increased pressures are harder and the ride comfort deteriorates, the handling changes too, especially in the wet where you will find over infalted tyres will spin more often.

Hope this helps.

 

[warwound]

Well i've put 30psi in each tyre - front and back - and will see how it drives for the time being.

I noticed when setting all tyres to 30psi that the rear tyres no longer had 36psi in them.
It was a very hot day when i measured 36psi in the rear - so those readings can be considered maybe false.

Martin.

 

[Lefthooker]

sure, when its warm the pressure does rise a little, same as after driving a long distance.

 

[Jen]

mine are 32 front, 30 rear.
so for your car Id say 30 all round is about right
your best doing it on a cold day, warm day figures will be well out

 

[pdc78502]

thats all i put in mine 30psi all round

 

[mickydoos]

Me good ol haynes manual says 27 front, 24 rear, but i got with 28 all round, seems a good idea, i oftenly have stuff in the back

 

[Coope]

i put 30 in the front n 32 at the back

 

[MarkGSi]

I usually put 31 in the front and 34 (205/50/15) in the rears and i often check for uneven tyre wear but all seems ok for the last few years. I find that the economy is better with the tyres at a greater pressure but i do agree the ride is harder and although i drive like miss daisy it is very easy to spin the wheels in the wet. I find that garages pressure lines vary greatly, i've got one of those halfords pocket gauges and it's never the same as what the garage air line says! It's very important to check the pressures cold or within a mile or so as that does make a difference and remember that most handbooks will state that tyre pressures apply to the make that were fitted at the factory.