On 11/5/2014 10:24 AM, Jeff Strickland wrote:

snip

DO NOT PAY EXTRA FOR NITROGEN. This is snake oil for tires. It might
work as claimed, but the air we breathe already is full of nitrogen. My
only point is, do not pay an upcharge for nitrogen. If they do it for
free, then do not refuse. But do not pay extra.

It isn't just the fact that it's nitrogen versus a mix that includes
nitrogen, there are other reasons for using nitrogen versus air as well.

The reason that Costco doesn't charge for nitrogen is not a marketing
ploy, the use of nitrogen reduces failures and Costco is one tire store
that actually honors its road hazard and tread life warranties. The cost
to them of including nitrogen is trivial given the benefits to them.

If you have a source of pure dry air for your tires, and check the
pressure often, and adjust for temperature changes, then plain air is
just fine. Tire stores will have driers on their compressors to remove
some moisture from air but it's not as moisture free as nitrogen.

But you're right, paying extra for nitrogen versus dry air isn't worth
it since most tire stores charge at least $5 per tire for it. And of
course you can always go to Costco and add nitrogen to your tires for
free. They have a hose there near the entrance to one of the bays.

One issue that comes up more and more is very sensitive TPMS systems. If
you're right at either edge (high or low) then pressure changes due to
tempearature will activate the TPMS warning light. Dry nitrogen has less
pressure changes due to temperature than moist air.

One other thing, is if you have a TPMS sensor fail (flashing TPMS
warning light at start-up) Costco does replacements at a cost far less
than the dealer. The batteries in the factory sensors fail at about 7
years. I just had them replace one last month. The next time I get new
tires I'll have them replace the other three since they are all going to
fail within a year and if they change them while they are doing mounting
and balancing there's no additional labor charge.