Those tyres never lost any pressure over their lifetime which was over 5 yrs and 50,000 miles,

Impossible - even with nitrogen, which diffuses less easily than the smaller oxygen molecule. See Fick's first law of diffusion.

who knows?

Physicists.

<< Many years I had a couple of Quatrac Lite tyres fitted in Sheffield they did a nitrogen fill free as standard. Those tyres never lost any pressure over their lifetime which was over 5 yrs and 50,000 miles, The tyres always looked in excellent condition, no microcracking or drying out of the rubber.

Never had this with tyres filled with air. May have been coincidence, perfect tyres, professional tyre fitters, the nitrogen fill or a combintion, who knows? >>

I suppose if we accept that the N2 molecule, being slightly 'fatter' than O2, might escape slightly less readily, tyre pressure might stay a bit longer after a nitrogen fill. But as the main escape route is via the beads, the valve, or a puncture, I suggest that will be a secondary effect.

And as the N2 is INSIDE the tyre, I can't see what it can really do to prevent atmospheric cracking on the outside, where that is mainly accelerated by sunlight. The main advantage of a nitrogen fill is that it will be bone-dry from a cylinder, not just compressed ambient atmosphere, which will certainly be damp.

Edited by Andrew-T on 19/08/2021 at 14:26

I'll admit my memory isn't that great these days, but I don't remember ever not paying for air, so I'm a bit baffled as to why it is such a big deal for the OP?

Drat! There goes my scheme to build a bike with a holding tank and an air wrench to ride from garage to garage enjoying free power

Free air and water costs money to provide - investment, maintenance. It also takes up space on the forecourt which may reduce customers using the shop or buying coffee.

Go to the supermarket for a can of baked beans - you don't normally get a free tin opener. So why should air and water be different.

Last time I looked, every can of beans on sale had a can opener built in. Just pull the ring pull.

Go to the supermarket for a can of baked beans - you don't normally get a free tin opener. So why should air and water be different.

Precedent. i.e. because they used to be.

But you knew that, really, didn't you?

I'm glad I gave up smoking in 1990, SWMBO has cut down but hasn't managed to stop completely.

It's all to do with self-perception. SWMBO still clearly self-identifies as a 'smoker'.

What is the reply to an offer of an unwanted ciggy? Smoker - 'No thanks, I'm trying to give up'. Non-smoker - 'No thanks - I don't smoke'.

Imagine the perception of the one vase/two faces picture. (google it if you don't know it). It requires a mental switch to go from one to the other, but the picture is exactly the same. The secret is to do the same with your self-perception; smoker to non-smoker. Same brain cells, different perception. Hope this helps someone...

'Free air'! Blimey - that takes me back, to getting tokens at the petrol station to exchange for cheapo glass tumblers and petrol costing £1.30 a gallon.

When I first had a car petrol was 3/11d a gallon, some places gave Green Shield stamps too.

Green Shield Stamps - I can just about remember them! My parents taking books of them to exchange for Go-knows-what at Argos (?) or similar back in the early 80s I think.

Just the other day it struck me that way back when petrol was 4 shillings a gallon, so was a packet of 20 cigarettes.

Now petrol is 'only' about £6.30 a gallon but the cheapest cigarettes are about £10 for 20. Shocking price, 10 shillings each in old money, I suppose the bulk of the price goes into the Chancellor's pot for schools and hospitals etc.

I'm glad I gave up smoking in 1990, SWMBO has cut down but hasn'y managed to stop completely.

Nasty habit. And a b***** expensive one too. My dad stopped 15 years ago after a health scare, which ironically probably helped pay for some nice holidays and a new car since. My vice is (still) sugary things (I'm tea totalled), despite being in my late 40s now.

Trying to cut down on that myself, not just for health reasons, but because quite a number of my fave (sugary) foods are now very expensive themselves in pandemic times. I can recall buying cans of coke for and Mars bars for 20pin my youth. Hardly cheap today (the latter being considerably smaller).

I miss the 1980s and 90s. I must be getting old.

I miss the swinging 60s, many things have gone downhill ever since!