On 1/5/2016 9:52 PM, Ed Pawlowski wrote:
On 1/5/2016 10:06 PM, Don Y wrote:


We're back at Costco every week or two having them add nitrogen to
the tires. On a cool day (30-ish in the AM), tire pressure (all
around) will be low. However, on a warm/normal day (80-ish in the PM),
pressures will be high -- TOO high if we'd added nitrogen on one of
those colder mornings!

I use 80% nitrogen.

Adding every week or two seems like a lot of seepage. I've not had a car yet
that could not go 3 - 4 months

We *add* because I *bleed* off the excess pressure. Ambient has changed
~60F in the past 4 weeks.

As I stated elsewhere, TPMS claims tires are presently at 38/36 at 67F,
sitting in the garage for 6 hours (51F outside). In a few days, we'll be
at freezing when SWMBO heads off for an early morning class. A few
of weeks ago, 80 degrees in the afternoon. Two weeks ago, 21-24 at night.
In another couple of weeks, 80 will be the norm, again. Then, +10F every
month until we're at 110.

When the pressures are "in your face" (on the dash), you're less likely
to ignore those low *or* high pressures (than you would, otherwise, if
you had to manually check pressures!).

So, you pick a temperature and a pressure and *hope* the weather
stays reasonably constant. As all *I* can do is bleed pressure from
the tires, I have to rely on Costco to put it back in when the
temperatures fall (again).