I'm curious about this trend of using nitrogen to fill tires. I hear dubious things like it helps performance of the tires. I've also heard it allows the tires to cool faster.

I thought I'd ask the seasoned folks on the RWD forum for opinions. So what gives?

-JSBB

A tyre inflated with nitrogen doesn't change pressure with changes in temperature anywhere near as much as one filled with air. If its 30 psi at standard ambient temperature, it stays near 30 psi regardless. So the wear rate is less when running at fast speeds on cold tyres. Consequently there's no need to check and adjust pressures according to what type of driving you'll be doing. Handling characteristics remain constant too.
Racecar tyres are nitrogen filled for those reasons. A couple of psi difference in a racing slick can make a ton of difference to a car's performance.

Nitrogen has better compresability, mor rather less compressability than air, about 20%, since air is ~80% nitrogen. Now CO2, is even better........
I would think that any benefit from lower oxidation, leaking, or thermal effects would be so minimal that it is not the main goal. Lower compressibility means less dive in cornering due to the tire compressing and distorting the relationship of tread to the road surface, meaning better handling. This factor is the basis for all gas shock absorbers, too, and would guess that it makes a difference with aircraft tires, also.
--
'89 245 Sportwagon, '04 V70 2.5T Sportwagon

It can't hurt, but I don't think the benefits are there. Sure, there is less oxidation, but is that much of a problem?

Aircraft tires are often filled with nitrogen, and it is a big advantage. Aircraft tires and tubes are still made of natural rubber, and the air leaks out through the rubber. Pure nitrogen leaks out more slowly, and you need to add air to the tires about half as much. Normally you need to add air to your aircraft tires every month or two, and it can become a regular chore.
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john

No moisture, no oxygen (so no oxidation), and the uniform size minimizes leaks are the promises I hear the most.

First two makes sense. Third ... even if not, the first two make sense enough.

-- Kane
--
Blossom II -'91 745Ti/M46 ... Bubbles -'74 144GL/BW35 ... Buttercup -'86 245GL/AW70
The Wayback Machine -'64 P220/M40 ... The ParaBox -'90 745GL/AW70

Oxidation?

Of the rubber?
--
Norm Cook Vancouver BC; 1989 745T 200,000KM

The thermal conductivity of nitrogen is within 1% of air; not much effect.
Helium, now...
--
Jim McDonald

I don't know if helium would be a good idea. At the least, the car would tend to rise up and lose traction. It may even rise up into the air and float. In that case a propellar or converting the exhaust into a jet would be needed to get where you are going. I haven't figured out the means of steering yet, maybe a rudder or steering jets?

I seem to remember that nitrogen is the least expensive bottled gas. That may answer why it is used.