Anyone filling their tyres with Nitrogen and any benefits ?

[maisbitt]

Total gimmick - Costco leading the way with Nitrogen filling in the UK.

Costco are the same knackers that insist you put your rear wheels on the front when you replace your front tyres, so the new ones go on the back. It is so much safer apparently - they just want you to wear out the back ones quicker by putting them on the front (and so getting 4 new tyres out of you in the not too distant). This is complete rubbish - yes, a car needs a few hundred miles run in for optimal tyre grip, but does that mean that when you get a brand new car that it's a death trap? Same applies if Costco replace all 4 tyres.

They did this to me last time, swapped the rears for the fronts, without balancing the wheels before they did so, and it felt like Fred Flintstone's car until they put it right.

Last time I go to Costco for tyres!

If a car tyre is filled with air (78% Nitrogen/21% Oxygen/1% others), and the oxygen preferentially escapes over time as it is a smaller molecule, then when you top up, the oxygen lost is replaced with air that is 78% nitrogen.

Say that a tyre has 30 litres capacity, you fill it with air, and 23.40 litres is Nitrogen. Over a period, the oxygen escapes first, so you top up with air again when there is 23.70 litres left (all Oxygen gone, Nitrogen and 1% other remains), then 6.30 litres gets added (4.91 litres is Nitrogen).

After that 1 theoretical top up, you tyre air is now 94% Nitrogen, after 2nd top up your air is 98% Nitrogen, 3rd = 99% nitrogen.

That is a simplistic model assuming that only Oxygen is lost, but Oxygen is more likely to be lost than Nitrogen, so a few top ups and you're at virtually pure nitrogen anyway.

If you're worried about oxidation of the tyre, this would only be a problem if your tyres were over 10 years old, and lets face it, the outsides of the tyre are exposed to oxidation and UV on a daily basis. Oxidation of the wheel itself shouldn't be an issue for those with alloys (how many people don't have alloys now?)

[Captain Answer]

Except the nitrogen and other gasses escape aswell

[maisbitt]

Captain answer - I covered that one - the other gases do escape, but at a much lower rate than the oxygen, so my model is roughly true. Where's that hose?

[rick vandal]

We are all filling our tyres with (mostly) nitrogen!

[Brownpants]

I did it once. Did nothing at all. Wouldn't bother again

[yorkshiregit]

A bit of a con from the tyre fitters to screw a few pounds out of you, air is 78% nitrogen. tyres on aircraft/racing cars will be filled with it though. Free air top up at morrisons if you spend £15 on fuel

[Whippy53]

Ooh! That's generous, free air, fancy that. Shushh, don't tell the government.

[dghdgh]

To be fair it gives a better temperature stability providing constant tyre pressure. As I drive to Spain now and again I get my tyres filled free at costco, its not costing me anything so I go for it.

[yorkshiregit]

In the UK the toilets are free but you pay for filling your tyres, Germany the air is free but the toilets you pay for..............

[Grant620]

IIRC 5th Gear did a test and found, if anything, the car was LESS stable with Nitrogen!