How to achieve equal tyre pressure?

Mortymoose

Mortymoose

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Our local garage has a forked up pump>

I spent the good part of the day trying to get my tyre pressures correct....

I always carried one of those manual tyre gauges, first round, it showed all four tubes at the required 210....

I then placed on my tyre pressure indicators, those wireless things and got four different readings....203,207,2013,2011....

Do the garages in your country have proper tyre pressure gauges then? How on earth do I achieve equal pressure across all four tyres?
 
pressure cannot remain constant, look at variable and basic science
 
Mortymoose said:
Our local garage has a forked up pump>

I spent the good part of the day trying to get my tyre pressures correct....

I always carried one of those manual tyre gauges, first round, it showed all four tubes at the required 210....

I then placed on my tyre pressure indicators, those wireless things and got four different readings....203,207,2013,2011....

Do the garages in your country have proper tyre pressure gauges then? How on earth do I achieve equal pressure across all four tyres?
Click to expand...

The pressure in the tyre will change depending on the temperature of the wheel/gas inside. When you fill the tyre from a reservoir the gas cools as it expands into the tyre. When it gets to outside temperature again the pressure will increase slightly as it warms (depending on how fast it was filled, what the initial pressure is and what the change in temperature is from filling to outside temp, the change in pressure may be slightly noticeable say a couple %) You don't need to perfectly balance all tyres, more or less is usually enough.

If you are really into it though, hook up a bicycle pump to the car wheel with a gauge and fill it yourself slowly to desired pressure. Most gauges are ~95% accurate to true values.
 
Mortymoose said:
Our local garage has a forked up pump>

I spent the good part of the day trying to get my tyre pressures correct....

I always carried one of those manual tyre gauges, first round, it showed all four tubes at the required 210....

I then placed on my tyre pressure indicators, those wireless things and got four different readings....203,207,2013,2011....

Do the garages in your country have proper tyre pressure gauges then? How on earth do I achieve equal pressure across all four tyres?
Click to expand...

Are your tyres meant to be at 2.1 bar, and you get readings of 2.03, 2.07, 2.013 and 2.011? Those are quite close, and it's unlikely that you'll better than that with a normal pump at a petrol station.

If those are PSI values are some other odd pressure reading, I have no idea what I'm talking about.

Edit: Ok, I assume that you're working in kilo pascals, my original advice stands, the numbers are close enough.
 
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Are these cheap and nasty monitors? I wouldn't expect any more accuracy than that, especially not between them all.
 
Does the issue not sit at the pump used to fill the tyres ?

We have one of those new digital machines here.
You punch in the required pressure and the machine does it's own thing, either inflating or deflating the tyre to get to your setting.
I was quite impressed by this new magic, hahaha
 
Last edited:
e4et said:
Does the issue not sit at the pump used to fill the tyres ?

We have one of those new digital machines here.
You punch in the required pressure and the machine does it's own thing, either inflating or deflating the tyre to get to your setting.
I was quite impressed by this new magic, hahaha
Click to expand...

I saw this at our garage, it was so intimidating. I then drove 4Km to another garage which had the old manual one.
 
zizo911 said:
I saw this at our garage, it was so intimidating. I then drove 4Km to another garage which had the old manual one.
Click to expand...

Hahaha, yeah. Me too. Standing in front of it looking all stupid.
Had to obviously tell everyone i saw about the magical machine i had just encountered.
 
Mortymoose said:
Our local garage has a forked up pump>

I spent the good part of the day trying to get my tyre pressures correct....

I always carried one of those manual tyre gauges, first round, it showed all four tubes at the required 210....

I then placed on my tyre pressure indicators, those wireless things and got four different readings....203,207,2013,2011....

Do the garages in your country have proper tyre pressure gauges then? How on earth do I achieve equal pressure across all four tyres?
Click to expand...

Stay in the car while someone else puts air in the tyres if you want the pressures to be exact. Your weight changes the pressures.

As already mentioned the pressure will increase as your tyres temperature increases through friction with the road. Set the pressure when the tyres are cold.
 
DanH said:
Stay in the car while someone else puts air in the tyres if you want the pressures to be exact. Your weight changes the pressures.

As already mentioned the pressure will increase as your tyres temperature increases through friction with the road. Set the pressure when the tyres are cold.
Click to expand...

Not that I know much about this, but one thing I do know is that you need to check pressures within a kilometer or two of starting up the car (as above - when tyres are cold). And that recommended tyre pressures change based on the load in the car.
 
DanH said:
Stay in the car while someone else puts air in the tyres if you want the pressures to be exact. Your weight changes the pressures.
Click to expand...

And then you pick up the kids and the groceries on the way home and you're forked again...
 
I had a thread on this as well. I found that different garages read the pressure differently as well, and they were quite off. Seems like you either have to live with it, or get your own pump and have it calibrated.
 
The only way to get proper accuracy would be to have a compressor at home to do this with while the tyres are off the car.

Anything remotely close otherwise is within reason. If you drove to the garage and turn more left than right to get there the numbers will be off unless you wait an eternity and even then...

Those new digital pumps at all the Engens are great so far and still accurate to my portable gauge. Old analog ones will be out by 30-50 Kpa.
 
Ecco said:
I had a thread on this as well. I found that different garages read the pressure differently as well, and they were quite off. Seems like you either have to live with it, or get your own pump and have it calibrated.
Click to expand...

It's the same as weighing yourself. Every single scale is calibrated differently, and manufacturing tolerances compound that.

You need to find a baseline that is as close to accurate that you are comfortable with, and then always reference the same scale/pump.
 
SauRoNZA said:
The only way to get proper accuracy would be to have a compressor at home to do this with while the tyres are off the car.

Anything remotely close otherwise is within reason. If you drove to the garage and turn more left than right to get there the numbers will be off unless you wait an eternity and even then...

Those new digital pumps at all the Engens are great so far and still accurate to my portable gauge. Old analog ones will be out by 30-50 Kpa.
Click to expand...

The weight of the car changes the pressure of the air in the tyres, the recommended pressures are for the tyres fitted to the car. Think of trying to blow up an inflatable pool toy with someone sitting on it.

The new style of having the gauge at the other end of the hose adds a load of variables which introduce inaccuracy between the tyre and the gauge, but maybe its better than having the gauge thrown onto the cement floor multiple times a day.
 
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