added air to my tires.

[talnlnky]

So... winter months coming... temps dropped and I noticed that my mpg's went from consistently 43+ to anything in the 40-42range. My last tank (although a small tank) was 40mpg's.

I decided that there were 3 main factors.
1: car taking longer to warm up
2: Tire pressure had dropped from 40psi in the summer months to 32psi currently
3: Due to colder temps... air resistance is higher due to the air being more dense.


Can't do much about problems 1 & 3... So I pumped the tires back up to 42psi.

First tank afterward netted 43.71, which is the higherst i've gotten since august 31st. Haven't noticed any difference in performance/handling or comfort either. So I'm happy with my 1-2mpg I gained back.

[voodoo22]

Don't forget winter gas is probably in your tank now as well. I've read where people check their tire psi weekly in the winter.

[talnlnky]

Originally Posted by voodoo22

Don't forget winter gas is probably in your tank now as well. I've read where people check their tire psi weekly in the winter.

maybe... oregon always has ethanol in the tank... has for years... so other than oxygenating it I don't know what would be different.

[b_hickman11]

Just get Nitrogen gas put into your tires and you wont have to worry about decreasing psi, no matter what the temp is outside. Most dealers in my area now offer this and it is usually free.

[talnlnky]

Originally Posted by b_hickman11

Just get Nitrogen gas put into your tires and you wont have to worry about decreasing psi, no matter what the temp is outside. Most dealers in my area now offer this and it is usually free.

well.... isn't air 80% nitrogen anyways?.... I'm fine for now.

[b_hickman11]

Originally Posted by talnlnky

well.... isn't air 80% nitrogen anyways?.... I'm fine for now.

maybe....buts its still not 100% The Nitrogen will not excape from the tire like regular air does.....

[TgrChica7]

Originally Posted by talnlnky

well.... isn't air 80% nitrogen anyways?.... I'm fine for now.

Yes it is, BUT N2 won't drop in pressure as fast as regular air, the tire pressure should stay more consistant due to there being no moisture in the N2 (with regular air you should check your pressures atleast once a month, with N2 you can go 3 to 4 before checking the pressure) AND is supposedly going to give you slightly better gas mileage as well (not completely noticable but its been told). I work in a tire and automotive shop so I work with this kind of thing all day 6 days a week. Most tire shops are starting to offer the N2 service now. Where I work its $2 per tire and then free after that. If you notice that your tires are low and you have N2 in the tires its perfectly fine to put regular air in them just when you can go back to where you got it installed and have them purge and refill with fresh N2 as the regular air will have diluted it.


ALSO on the inside panel of your driverside door read the placard, it will tell you the correct pressure that the manufacturer calls for in the tires DONT go off of what the tire says.... You could be over inflating your tires and that could cause uneven tire wear and possible hazards.

(Wow I feel like I am at work lol)

[YarisSedan]

Nitrogen is denser than oxygen. Thus harder for it to leak out. With oxygen you loose about 1 pound of air per month slowly from your valve stem. With nitrogen you loose maybe 1 pound every 6 months to a year.

[Smokey159]

Originally Posted by YarisSedan

Nitrogen is denser than oxygen. Thus harder for it to leak out. With oxygen you loose about 1 pound of air per month slowly from your valve stem. With nitrogen you loose maybe 1 pound every 6 months to a year.

Leak out???? Ummm, you use nitrogen because it is less suseptible to temp change as the tire warms up.

[bigjimmysrock]

Originally Posted by Smokey159

Leak out???? Ummm, you use nitrogen because it is less suseptible to temp change as the tire warms up.

it leaks through the rubber not the valve stem...

[nemelek]

I run a special mixture for my tires.

78.1% Nitrogen
20.95% Oxygen
0.038% CO2
0.0018% Neon
0.0005% Helium
0.0001% Krypton
0.00005% Hydrogen

Free Nitrogen is one thing, but to pay $5 a tire like some places charge is another. I'll save my money for snake oil.

[voodoo22]

Originally Posted by nemelek

I run a special mixture for my tires.

78.1% Nitrogen
20.95% Oxygen
0.038% CO2
0.0018% Neon
0.0005% Helium
0.0001% Krypton
0.00005% Hydrogen

Free Nitrogen is one thing, but to pay $5 a tire like some places charge is another. I'll save my money for snake oil.

It's like the bottled water craze, where often people are paying for bottle water that's even worse than the water coming from their taps.

[natethegreat38]

Originally Posted by talnlnky

Can't do much about problems 1 & 3... So I pumped the tires back up to 42psi.

First tank afterward netted 43.71, which is the higherst i've gotten since august 31st. Haven't noticed any difference in performance/handling or comfort either. So I'm happy with my 1-2mpg I gained back.

As a tire professional, I feel that doing this is one of the worst things you could do. If you live in a colder climate that gets snow and/or rain you want to have your tires properly inflated to ensure proper traction in the snow/ice/rain. Over inflating the tires (as is the case @42psi) will narrow the contact patch and result in less tire surface area contacting the road and less traction.

Personally, MPG takes a back seat to my safety and the safety of my passengers

[TgrChica7]

Originally Posted by natethegreat38

As a tire professional, I feel that doing this is one of the worst things you could do. If you live in a colder climate that gets snow and/or rain you want to have your tires properly inflated to ensure proper traction in the snow/ice/rain. Over inflating the tires (as is the case @42psi) will narrow the contact patch and result in less tire surface area contacting the road and less traction.

Personally, MPG takes a back seat to my safety and the safety of my passengers

Glad to see there is another tire professional on the forum! I'll back you 100%!! I've been in too many Michelin/BFG, Goodyear, Yokohama, Hankook, Toyo, Pirelli and a few other classes and Ride & Drive's to have people tell us we are wrong...

[thebarber]

42psi in your tires? are they worn down the center?

damn, i ran too high of a tire pressure in my winters one time and i had to buy 2 new fronts by the end of the season (and i didnt rotate them) as they were on the wear bars down the center of the tire....

[natethegreat38]

^^^ He speaks the truth... It's hard to convince people otherwise, but it doesn't save you money by over-inflating your tires; sure you get higher MPG, but you are replacing your tires more frequently offsetting the savings.

[gid]

Originally Posted by natethegreat38

^^^ He speaks the truth... It's hard to convince people otherwise, but it doesn't save you money by over-inflating your tires; sure you get higher MPG, but you are replacing your tires more frequently offsetting the savings.

stiffer tires from overinflating can cause premature wear and tear or sudden damage on the shocks , struts , tie rod ends , etc. when hitting those potholes of winter and spring . Tires are considered part of the suspension . That's why there's a setting / limit by tire manufacturer and car maker . I can see at the most 36 p.s.i. , I try to keep them between 34 > 35 p.s.i.. This time of year is a pain the from the variation of temps . Try to check them every week if you can .

[voodoo22]

Originally Posted by natethegreat38

^^^ He speaks the truth... It's hard to convince people otherwise, but it doesn't save you money by over-inflating your tires; sure you get higher MPG, but you are replacing your tires more frequently offsetting the savings.

It depends what you consider over inflating. If you consider going higher than the car manufacturers recommendations, you're wrong and if you consider going a bit over the max sidewall on newer tires you're wrong. If you mean going to 100+ psi or something like that, you may be right.

There is a growing number of people who inflate to maximum sidewall pressure and beyond with no ill affects and loads of various benefits like better MPG, handling, braking etc. Any statements to the contrary are made by people who do not know the facts.

My latest pair of winters have been at a constant state of 50 psi or more and same goes for my current all seasons. I have over 40,000 combined kms on these tires and they still exhibit virtually no wear. Inflating to maximum sidewall and a little higher has only one downside and that is ride comfort, anyone telling you any different either doesn't know what they're talking about or is a liar.