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L8 APEX
11-20-2008, 11:21 PM
Take a few minutes while it is cold and set your winter tire pressures. Most tires will lose a few pounds when it drops 40 degrees. I also read an article about the benefits of nitrogen over air. I think it said nitrogen molecules were larger than air so it leaked out much more slowly. It also reacted less with the wheel and rubber than air. We use to fill our race car tires with Nitrogen to reduce the pressure gain with heat inside the tire.

Sandman
11-21-2008, 12:05 AM
yup. I run nitrogen in my tires. For the garage queens it will help prevent flat spots on the tires.

L8 APEX
11-21-2008, 09:32 AM
I heard a few automkers factory fill with nitrogen.

Mark #2
11-21-2008, 08:48 PM
Just FYI,
http://www.getnitrogen.org/pdf/graham.pdf

But the key is really no water, dry air is within a percent or two.
We make this trade off all the time for costs in the semiconductor business for dew points in equipment.

N2 for street tires makes absolutely no sense at all versus dry air, I fill my tires at home with CDA (compressed dry air), you just need a dryer on the end of your compressor, same as what you need for spray painting.

WA 2 FST
11-21-2008, 11:09 PM
Take a few minutes while it is cold and set your winter tire pressures. Most tires will lose a few pounds when it drops 40 degrees. I also read an article about the benefits of nitrogen over air. I think it said nitrogen molecules were larger than air so it leaked out much more slowly. It also reacted less with the wheel and rubber than air. We use to fill our race car tires with Nitrogen to reduce the pressure gain with heat inside the tire.

Hmm... my wife's new Denali supposedly has Nitrogen-filled tires. This AM they were all at 26psi (32psi is recommended). Granted, it has been cold for a few days, and her truck sits outside under the carport... so maybe it took longer than others would have filled with typical "air". I mixed whatever was in there with whatever I have in my air compressor. ;)

L8 APEX
11-21-2008, 11:37 PM
32 is way to low for a heavy SUV esp with anything over 15" rims. I would check the side wall and split the diff. If she has 17" rims I would run 38-40 in the front and 36 in the rear. Vette's ride on 28-32psi...

WA 2 FST
11-21-2008, 11:55 PM
It has 20" rims. OEM recommendation is 32, I believe.

Silver_2000
11-22-2008, 12:03 AM
Just FYI,
http://www.getnitrogen.org/pdf/graham.pdf

But the key is really no water, dry air is within a percent or two.
We make this trade off all the time for costs in the semiconductor business for dew points in equipment.

N2 for street tires makes absolutely no sense at all versus dry air, I fill my tires at home with CDA (compressed dry air), you just need a dryer on the end of your compressor, same as what you need for spray painting.


I hope this helps clarify why O2 permeates faster through rubber than does N2 and a major aspect of why it is a good
idea to significantly reduce the amount of O2 used to fill tires by replacing most of the O2 in air with enriched N2. Since
N2 permeates through the tire rubber more slowly than would O2, using enriched nitrogen instead of air for tire filling
contributes to better maintenance of the proper inflation pressure for the tire. Better pressure maintenance contributes
to reduced tire wear, so that tires last longer and tire replacement costs are reduced.
A simple but approximately correct explanation of this lies in the mechanics of the flexing of tire walls. If proper inflation
pressure is maintained, the tire wall most effectively bears the weight of the vehicle. If pressure is allowed to fall too
low, extra flexing that occurs as the vehicle bounces somewhat along the road causes excessive mechanical fatigue of
the structure of the tire. Similar to flexing a wire coat hanger, this fatigue can weaken the tire faster than would be the
case were it kept inflated to a pressure more consistent with that intended in its design.

Seems your link concludes that nitrogen is a good thing

Razor
11-22-2008, 12:33 AM
Hint Aircraft use Nitrogen, but not readilly accessible. Shop air works for me.

L8 APEX
11-22-2008, 07:34 AM
I owuld never run under 40psi in a 20". The limited sidewall is prone to damage at low pressure. Read the front tires. I would run 40/36 at a minimum.

Mark #2
11-22-2008, 05:24 PM
Seems your link concludes that nitrogen is a good thing
It does, but the link was to show how absurd some are on this issue. The real concerns are water and temperature.

Water freezing can be issues for street tires and water boiling is an issue for race tires.

PV=nRT so temperature is really the concern, not N2 or O2 diffusion rates through rubber.

Checked the pressure in tires sitting for +5 years and they have dropped 5 lbs, don't think the differential diffusion rates are a concern, but I guess they have pure N2 in them now.:D

wesman
11-22-2008, 11:45 PM
I heard a few automkers factory fill with nitrogen.

Yeah, I know Infiniti has been doing it for a couple of years. Steph' FX had them, we never had an issue with air leakage etc.

--wes

my2002lightning
11-23-2008, 12:13 AM
I believe Stan/Ruslow runs nitrogen in his L tires.

He evidently knows what he's doing.

bobbywade69
11-23-2008, 12:35 PM
32 is way to low for a heavy SUV esp with anything over 15" rims. I would check the side wall and split the diff. If she has 17" rims I would run 38-40 in the front and 36 in the rear. Vette's ride on 28-32psi...


Alot of the new ones will through a light for over inflation usually GM sets the sensors at 32 and after 34-35 you get a tire light and under 28-26 you will get a light this is for new GM cars and trucks.

L8 APEX
11-23-2008, 09:20 PM
Yeah on track days I have seen the stupid high pressure warning on the vettes..