That's just not true. Dry air and nitrogen have exactly the same
pressure rise with temperature. Air with some moisture in it will have
a very slightly higher pressure rise with temperature (negligible for
our uses). That's why I said you can avoid even that slight difference
by using the dry air that comes from your dryer-equipped motorhome air
system.
Warning: Technical trivia follows: The "ideal gas laws" show that, for
a fixed volume (roughly the case for our tires), with dry air,
nitrogen or any other ideal gas, if you double the temperature, you
will double the pressure. The "trick" is you have to use absolute
units for the measured temperature and pressure. E.G. psia and
kelvins. Temperature in kelvins is equal to degrees Celsius plus
273.15. Psia is psig plus 14.7 (with a slight correction for
altitude). Water vapor is not an "ideal gas", so it behaves somewhat
differently.
So, if you are really paranoid about pressure rise with temperature
(e.g. driving your rig in a NASCAR race, where 1/2 psi matters), the
trick is to use dry air. Nitrogen is one relatively expensive way to
do this. Having a dryer on your compressed air supply is another way.
Bill Halberstadt
--- In Diesel-RVs@yahoogro
>
> Here's what I mean by stable. Check your tires temperature cold, and
> then hot. It will be different. With nitrogen it's the same.
Off-topic posts will be removed.
Please sign with your name (real or online name) and include the RV model you have.
To unsubscribe from this group, send an email to
Diesel-RVs-unsubscribe@egroups.com
Earn your degree in as few as 2 years - Advance your career with an AS, BS, MS degree - College-Finder.net.
Change settings via the Web (Yahoo! ID required)
Change settings via email: Switch delivery to Daily Digest | Switch format to Traditional
Visit Your Group | Yahoo! Groups Terms of Use | Unsubscribe
__,_._,___
No comments:
Post a Comment