Nitrogen filled tires & tires for sale spam

[Tim Rogers]

Mark Holden wrote:
"The benefit is that nitrogen is "dry" and doesn't have the water vapor
that's in your typical compressed air."

Very true.

"The water vapor condenses out when cold, and then turns back to vapor
when heated up.  So the more water that's in a tire, the larger the
expansion is under heat, so the more the pressure swing is between cold
and hot tires."

Err, almost.
Water vapor is usually still a vapor when its in your tires but it has a
much higher coefficient of expansion (meaning that for every degree of
temperature increase, it expands more than either N2 or O2) so it is almost
exclusively responsible for the pressure change as the tire heats up.

Jaret, I'm guessing your coworker who got the nitrofill may have been told
to keep her tires filled at a higher pressure (probably the hot pressure
level.)
Higher pressure in the tires equals less rolling resistance and therefore
better mileage.
This effect would be more pronounced if she mostly does short trips that
don't allow the tires to heat up (and therefore pressure up) very much.

Tim Rogers