Reducing tyre pressure

[MissyD]

I increased the tyre pressure at the weekend as the car was fully laden with people and luggage. Now its just me in the car , the pressure needs to be reduced, is this just a matter of pressing the valve to release the air? I know that may be obvious to you guys, but I wanted to check that was the correct way, thanks

 

[Chrishazle]

Remove the valve cap and use something like a matchstick to press the centre of the valve down and release air, checking periodically until you get to the required pressure.

 

[clk320x]

I would just set the pressure at a petrol station air compressor.

 

[ToeKnee]

I increased the tyre pressure at the weekend as the car was fully laden with people and luggage. Now its just me in the car , the pressure needs to be reduced, is this just a matter of pressing the valve to release the air? I know that may be obvious to you guys, but I wanted to check that was the correct way, thanks

That's exactly how to do it Sarah.

 

[MissyD]

I would just set the pressure at a petrol station air compressor.

Are you saying it will take the air out if I set it less than the pressure already in the tyre?

 

[Bellow]

Press the pintle - smell the rotten fish.

 

[colinallcars]

My MB inflation pump has a ‘-‘ button for reducing the pressure

 

[clk320x]

Are you saying it will take the air out if I set it less than the pressure already in the tyre?

Yes absolutely.

 

[Trickythemerc]

Never use forecourt air pumps, A they cost money B they are rarely accurate. I use a sealey cordless pump and double check with a proper dial gauge.

 

[alabbasi]

s this just a matter of pressing the valve to release the air? I

Yes, and use a gauge to check the pressure every so often,

 

[190]

Never use forecourt air pumps, A they cost money B they are rarely accurate.

Another good reason not to set pressures on a fuel station forecourt is that the recommended pressures are for cold tyres at ambient temperature. When the car is driven any distance the pressure will typically increase by 2 - 3 psi due to frictional heating. As the pressure increase is uncertain depending how far and fast the car has been driven it's hard to know how much extra pressure to add, so just simpler to check pressures when the tyres are cold.

 

[alecmascot]

so just simpler to check pressures when the tyres are cold.

and out of the sun......

 

[tonysmb]

If you have an individual 'pencil-type' of pressure gauge, many of them are shaped such that you can use the end opposite the measuring end to press-in the pin in the centre of the tyre valve to release pressure - just start by short bursts until you reduce to the new pressure.

 

[clk320x]

Never use forecourt air pumps, A they cost money B they are rarely accurate. I use a sealey cordless pump and double check with a proper dial gauge.

The one at my local Waitrose/Shell is free, and the pressure readings are identical to the car TPMS which we have verified with a manual gauge at the tyre shop.

 

[baxlin]

Another good reason not to set pressures on a fuel station forecourt is that the recommended pressures are for cold tyres at ambient temperature. When the car is driven any distance the pressure will typically increase by 2 - 3 psi due to frictional heating. As the pressure increase is uncertain depending how far and fast the car has been driven it's hard to know how much extra pressure to add, so just simpler to check pressures when the tyres are cold.

Good post. Sorry to spoil it with my attempt at humour…

Doesn’t ‘2 - 3’ equate to minus 1? Surely that’s a decrease not an increase?

. Don’t worry, I’ll get my own coat

 

[W1ghty]

I just use my seperate hand held pressure gauge to reduce pressure by just pushing it on and off the valve to let air out as I watch the pressure gauge .

 

[Mark9999]

and out of the sun......

It’s surprising how much difference it makes.

 

[ALFAitalia]

Never use forecourt air pumps, A they cost money B they are rarely accurate. I use a sealey cordless pump and double check with a proper dial gauge.

They are checked quite frequently these days........we (as a service centre) have ours checked once a year....its mandatory for our insurance and they get a LOT of use....they are rarely out by more than a LB... The digital ones are more accurate than the mechanical ones and take much longer to go off. The bigger problem is that you have to drive to the garage.....so no matter how accurate the gauge you will be testing the tyres when they are hot....so the reading will be rather higher than when its cold , when they should be measured. My old BMW 528i gave hot and cold pressures in the book!!!..and thing of the past and a bit hit and miss though!!

 

[slade1]

It’s surprising how much difference it makes.

Only check tyre pressure when cold.

 

[Mark9999]

I usually check mine first thing in the morning before the sun has had a chance to creep round. Even a few minutes of sun makes a difference.
Mark