Nitrogen?

Pipemajor

Hoot Mon!
:
Minnesota
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2017 CX-5 GT AWD
Just took delivery of a 2015 CX-5 GT AWD 2 weeks ago. I have a dealer coupon for a free nitrogen service which I assume evacuates the atmospheric air from the tire and replaces it with N (and gives you the funky green valve stem caps). I realize air is already 80% nitrogen with the balance being oxygen with traces of argon and carbon dioxide.

Since it's a free initial service, any disadvantages of the conversion?
 

Chris_Top_Her

Banned
Moderator
Contributor
:
San Antonio, Texas
:
'15 CX-5 Miata AWD
For free I would take it. Less sensitive to temp changes.
 

vroom

Member
:
CX-5 GS AWD 2014, Sky Blue Mika
Not even worth the trip to the dealer IMO. As you mentioned air is already 80% nitrogen. Besides, nitrogen is no less sensitive to changes in temperature than dry air. Any thing else you might hear is simply marketing bs. Damp air can be a problem though, since the humidity can condense at low temps. Since water takes up 1000 times less volume in its gas state than in liquid form you get a drop in pressure. That's why I always fill up my tires when it's cool and dry outside, and never in a garage where I just washed my car.

The only very slight advantage of nitrogen is not having oxygen in the mix. Oxygen can oxidize the rubber and wheel from the inside. The effect is so minor, it is negligible.
 

SayNoToPistons

Wheels, not rims...
:
CX-5 GT AWD w/ Tech, RX-8 GT 6spd w/ 'goodies'
Not even worth the trip to the dealer IMO. As you mentioned air is already 80% nitrogen. Besides, nitrogen is no less sensitive to changes in temperature than dry air. Any thing else you might hear is simply marketing bs. Damp air can be a problem though, since the humidity can condense at low temps. Since water takes up 1000 times less volume in its gas state than in liquid form you get a drop in pressure. That's why I always fill up my tires when it's cool and dry outside, and never in a garage where I just washed my car.

The only very slight advantage of nitrogen is not having oxygen in the mix. Oxygen can oxidize the rubber and wheel from the inside. The effect is so minor, it is negligible.

This. There was a test preformed on various "nitrogen fill stations VS normal air fill stations", and there is no difference. At the consumer level of nitrogen filling for tires, it is an absolute gimmick.
 

vroom

Member
:
CX-5 GS AWD 2014, Sky Blue Mika
These tests sell automotive magazines but are useless, physicists have known this for 200 years in the form of the ideal gas law! This law states that all gases increase in pressure at exactly the same rate when temperature increases. The law is accurate to about 5%, but since air is 80% nitrogen anyway, the difference drops to 1%, and since most components of air have very similar thermodynamic properties, the difference is even smaller. The pressure gauge the guy uses to fill your tires with nitrogen doesn't even have that level of accuracy.

A good read on why nitrogen makes no perceptible difference at the consumer level can be found here.
 
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Pipemajor

Hoot Mon!
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Minnesota
:
2017 CX-5 GT AWD
Well, I did invest in digital tire gauge. Reads to .5 PSI increments. A couple of the tires read 37.5
 
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GA prior 16 CX5 GT
:
20 CX5 GT + Prem
Per the marketing info, the oxygen molecule migrates through the rubber over time. The nitrogen molecule migrates at a much slower rate so the tire does not loose pressure nearly as quickly so you are driving with the correct pressure for a much longer period after you set the pressure.?
 

vroom

Member
:
CX-5 GS AWD 2014, Sky Blue Mika
Per the marketing info, the oxygen molecule migrates through the rubber over time. The nitrogen molecule migrates at a much slower rate so the tire does not loose pressure nearly as quickly so you are driving with the correct pressure for a much longer period after you set the pressure.?

The superlatives (much, nearly) in the marketing info are a bit misleading. Oxygen does have a slightly higher diffusivity across rubber than nitrogen, but the difference is slight. Consumer Reports did the experiment, and found that after a YEAR, the difference between air and nitrogen filled tires was 1.3 psi with both loosing pressure. This is very small compared to the nearly 10 psi typical variations for both air and nitrogen throughout the year in northern latitudes due to temperature alone.
 

slippin3

Member
As a former owner of a tire shop.....

Fill them with Nitrogen if you'd like. If it's free, and your at the dealership anyways, it's a free check and fill. Would I bother going out of my way, or paying for it? Never. Lol

John
 

Chris_Top_Her

Banned
Moderator
Contributor
:
San Antonio, Texas
:
'15 CX-5 Miata AWD
Well, there are those dorky green stem caps... ;)
true, funny because I thought the same thing when I accidently bought a presta valve inner tube for my bike, which also uses a green cap