Nitrogen in tires

[henryroten]

I was thinking that with this hot summer and all the reports about tire failures I would try replacing the air in my tires with Nitrogen gas. I know that race car drivers everywhere use it as it doesn't expand with heat, keeping the tire pressure from over heating and inflating the tires to dangerous levels (Nitrogen gas is also used in shocks for the same reasons).

So my first attempt (pulled the valve stem and tried to squeeze the air out) went fairly well but still I found that the tires would grow in pressure 3-4 pounds on hot highway speeds. So I then let them cool off and topped them off at 34 front and 40 rear (didn't start over, just added Nitrogen) and found that after 75 'spirited' miles on the twisties that the front stayed at 34 and the rear grew to 41.5 pounds. Not bad! the tires also felt (to the hand) to be cooler so I am so far pretty pleased with the swap.

The other benefit is that pressure should stay equal in elevation changes which are plentiful in the area where I do most of my riding (northern Utah).

Just thought I would share.

[biggus]

I read about filling your tires with nitrogen from the makers of Dynabeads. Glad that someone on here has actually done it.

I have wanted to do this to mine since I live in Thailand where the temps tend to be pretty hot.

[Unkgd]

Compressed air always contains moisture - which is the major contributer to rising tire pressure when the tire warms up.
Bottled nitrogen contains significantly less moisture (on the order of ppm if I remember correctly) hence - less pressure rise when heated.

It would be possible to use an eductor to remove the air from the tubes prior to refilling with nitrogen - which would save one step from what the OP did.

I have a bottle of nitrogen sitting in the hanger - might have to finally get arround to doing this

[catalina38]

I prefer 78% nitrogen.

[biggus]

Originally Posted by catalina38

I prefer 78% nitrogen.

Must be a diver.

[bhorocks]

good idea...

[catalina38]

Originally Posted by biggus

Must be a diver.

I'm trying to avoid oxygen toxicity

[timekeeper]

I used Nitrogen in the tires of my GTR for 2 years. The hassel was NOT worth the results.

[sstewart]

Molecules are larger,less leakage.

[syzygy9]

Hate to be the bearer if bad news but N2 in conventional tyres is a complete waste of time (apart from the fact that good ol' air in almost 80% N2) - great way for tyre retailers to make some extra money though.

If however, you live in a very humid climate, conventional unfiltered air may have a lot of water in it which when condensing, evaporating or freezing (whatever the case may be) will result in pressure changes (which is one of the reasons commercial jets have N2 in their tyres). You could also argue that "pure" nitrogen does not have very much oxygen or water in it and being relatively inert does not react with the tyres, although I haven't heard of too many tyre failures caused by the rubber tyre compounds reacting/oxidising with air. With regard to pressure changes - pure air (no water) and N2 probably are both as close to an 'ideal' gas as each other and hence have same P to T ratios.

[Nut Clutch]

Originally Posted by Unkgd

Compressed air always contains moisture - which is the major contributer to rising tire pressure when the tire warms up.
Bottled nitrogen contains significantly less moisture (on the order of ppm if I remember correctly) hence - less pressure rise when heated.

Right on.

When I raced karts, I carried a nitrogen bottle around because it was a readily available source of consistently low moisture inert air. The size of the nitrogen molecules was not a concern. The important thing was to see a low and consistent tire pressure change due to heat. Nitrogen provided that. Also, you can get it from Praxair for something like $20 + deposit for a reasonably sized cylinder at 2000 psi. Just add a regulator and you are off to the races.

The 2000 psi cylinders are much more convenient at a remote location than a compressor that requires power and is noisy or a 5 gallon 125 psi tank that runs out quickly.

[SE Steve]

My experience with nitrogen is with commercial truck tires. From what I have been told is that nitrogen molecules are larger than oxygen molecules. So over time the nitrogen filed tires will lose less air pressure from leaking through the rubber layers . Nitrogen keeps the air pressure more stable day to day. Example I was using nitrogen in the steer tires of my truck 18 wheeler axle loaded at 1200lbs tire pressure at 120 psi cold. After 600 hundred miles pressure would be around 140psi. The next morning around 118. so it would lose a couple lbs per day. With straight O2 tires would lose 5 psi per day. My opinion is nitrogen is a little more stable than straight air in tires. In motorcycle tires I can't see it making a big enough difference to worry about. Truck tires usually come apart because they don't have enough air pressure. Could be they have a slow leak. When truck tires run low they over heat and explode. If your worried about tire failer stop and check your tire pressure if it's higher than you like take a break and let your tire cool down. Just my 2 cents

[Peanuts]

I used Helium in my 990 Adv tyres. The whole bike now weighs less than my 250 EXCF.


Honest ;)

I also lube my chain with snake oil

[Azmontana]

Originally Posted by timekeeper

I used Nitrogen in the tires of my GTR for 2 years. The hassel was NOT worth the results.

What hassle? It's a piece of piss to fill your tyres with Nitrogen.

[Nomadix]

For best results, I'd suggest a mixture comprising roughly 78% nitrogen, 21% oxygen and 1% argon. Don't worry about trace amounts of other gasses.

Also, for optimum performance and longevity, I recommend snake-oil in your engine .