Air pressure in tyres

[geared]

hth .......................

 

right, had to read it three times to understand what he was saying.

[alankearn]

Easy Peasy, do what I did with my first cars about 55/60 years ago

 

Walk round the car kicking each tyre in turn and saying that ones OK or that one needs a bit in.

 

First car

Click here

http://my.jetscreenshot.com/26313/20160511-kc1u-132kb

[Gamston]

Here we go again I have found a sticker in the box the wheels came in

Says warning pressure range 0.14-0 bar to 0.27 bar / 2-4 psi still dose not mean much to me

They will be very low pressure if they are balloon wheels for a wheel chair. It does just mean 2 - 4 psi in comparison to a car wheels which are 26 - 30 psi. Think of the pressure being 10% of what your car tyres are and use a bike pump.

[cgksheff]

Atmospheric pressure is approximately 15psi. By that reckoning the tyres don't need inflating at all; just put them on them and go.

That clearly can't be correct so the label on the tyres could be incorrect.

 

The fact that you appear not to be aware of the difference between psi & psia, suggests that you should refrain from posting on this thread.

[Eater Sundae]

Sorry but i did not say the wheels that want blowing up are balloon wheels for a wheelchair so we can go on the sands on holiday 12 inch diameter X 9 inch wide

I have purchased them from China but on the tyre it only says tyre pressure

2-4 psi thanks

 

4 wheels at 9 inches wide, supporting the weight of a wheelchair and one person. Say the chair and person weighs up to 200 lbs. Then 4 psi would require a total area of 50 square inches to support that weight. That would equate to approx 12 square inches per tyre. At 9 inches wide, that would need a contact patch only 1 1/3 inches long.

 

So 2 to 4 psi sounds very reasonable.

[spilldig]

Over the years I've had a lot of trouble with tyre pressures. First off, one of the tyres on our car should be 28 psi, but it goes down after a couple of weeks to about 20 psi, so you might think it's a slow puncture but it doesn't drop below 20 psi no matter how long you leave It. I also have a wheelbarrow the tyre of which goes flat in a few hours and I have removed the inner tube on that and submerged it in water and no leak shows even when squeezed. I also have a cycle that is in storage at the moment and the back tyre on that goes flat in about a day even though I have had the whole thing submerged in water and no airbubbles show with that either. All three are a mystery to me. Has anyone had the same problem and if so what was the cause ?

[WasThatWise]

With car tyres it can be a leaky valve or the seal of the tyre to the rim, you can try pumping the tyre up to say 40 psi leaving it for an hour then reduce it to normal pressure this might seal the rim.

[davyboy]

Atmospheric pressure is approximately 15psi. By that reckoning the tyres don't need inflating at all; just put them on them and go.

That clearly can't be correct so the label on the tyres could be incorrect.

 

You are joking of course.

Tyre pressure is xpsi above atmospheric pressure

[Mikes10]

Sorry but i did not say the wheels that want blowing up are balloon wheels for a wheelchair so we can go on the sands on holiday 12 inch diameter X 9 inch wide

I have purchased them from China but on the tyre it only says tyre pressure

2-4 psi thanks

 

take a look here:

 

http://www.wheeleez.com/about-low-pressure-wheels.php

[spilldig]

With car tyres it can be a leaky valve or the seal of the tyre to the rim, you can try pumping the tyre up to say 40 psi leaving it for an hour then reduce it to normal pressure this might seal the rim.

 

I take your point WasThatWise but both the cycle wheel and the wheelbarrow inner tube I submerged in water while fully pumped up and no airbubbles emerged. It is weird. A strong possibility of that with the car though with a valve that only leaks down to 20 psi.