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Absolutely no good reason to use N2 for bike or cars tires but if you want to feel free. Your pressure drop is probably primarily due to temperature but they should not be set the same!

I never trust the local mechanics to know how to correctly set tire pressure or oil level. Sad but true.
 

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On 2006-12-12 13:38, DavePreston wrote:
The advertised benefits are that nitrogen molecules are 4 times as large, and therefore leak much more slowly. In addition, for track day nuts, nitrogen does not change pressure nearly as much when the tires are hot. The cost is pretty minimal (if I recall we charge $13 for both tires) so it is worth a test.
1. Air is 78% nitrogen, N2, and 21% oxygen, O2. So even if you put air in the tire, it's already 78% nitrogen. Many of the so called nitrogen generators don't produce much more than 90% nitrogen.

2. At relatively low pressures (ie tire pressures) N2, O2 and water vapor will all behave as ideal gases, and follow PV=nRT. Pressure will increase or decrease to the same extent as the temperature increases or decreases regardless of which gas is in the tire. (Even at 300 psi, which is about 20 atm, there is little deviation from ideality.) Therefore the comments about N2 not changing in pressure as the temperature changes are without merit.

3. The rate of effusion (or diffusion) of a gas through a porous membrane depends on the molar mass and to some degree on the molecular diameter. N2 and O2 are almost the same size and N2 is lighter than O2 (28 g/mol vs 32 g/mol) so if either gas were to effuse out of the tire, nitrogen would do it more quickly. Luckily, tires are designed not to be porous membranes.

4. N2 and O2 both have essentially the same specific heat capacity, about 1.0 J/gK, and thermal conductivity, about 0.00026 W/cmK. Water vapor has a specific heat capacity of about 2 J/gK. But remember, water vapor will constitute less than 1% of the air in the tire. So the idea that N2 has different heat handling properties is also without merit.
 

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On 2006-12-12 15:08, scgstuff wrote:
DR,

I looked at your sig line and saw the patents. I am assuming these are yours since the user name and the patent registrant are the same name. Does Triumph pay for the use of these in the S3? Just curious how that works....

Shawn
The companies I used to work for own the patents, I got a dollar for each one. Triumph uses Keihin injectors & ECUs in the 1050, SAGEM injectors & ECUs are still being made in France and were last fitted to the '06 955 Daytona and Tiger.
 
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