For every 3psi i lose 1mpg

[JEDI]

i usually get 29mpg in mixed city/hwy driving.

a couple weeks ago was no different. yet i only got 26mpg. I've NEVER had 26mpg in the 25k miles i've driving my 3i.

And last week was also 26mpg.

then i noticed my front passenger tire was kinda low on air. my air gauge measured at 23psi. i usually have all tires at ~32mpg. a quick look and i didnt notice any nails or anything. so i put it back at 32psi.

a week later, i notice my tire kinda low on air again (22psi). i filled up on gas (again 26mpg) and took it to the shop. there was indeed a small nail in my tire.

i guess at 23psi, air pressure was lower than the pressure holding the nail in so the leak was minimal at that point.

so if being 3psi lower = 1mpg loss, does that mean for every 3psi higher i get +1mpg?

 

[Howard]

Only when it does. You can't extrapolate since the tire pressure vs mpg function is not linear.

 

[kumanchu]

you will have better gas milage with skinnier tires because of lower rolling resistance. . however, if you increase the tire pressure you will have uneven tread wear, and the life of your tires will be shortened. on top of that your car will not corner quite as well.

my guess at least.

 

[IAteYourMother]

interpolate, don't extrapolate

 

[MercenaryForHire]

I was thinking you meant boost pressure.

- M4H

 

[holden j caufield]

overinflating is bad for other parts of your car suspension, tire wear, etc.

 

[nakedfrog]

Originally posted by: MercenaryForHire
I was thinking you meant boost pressure.

- M4H

Ditto

 

[AgaBoogaBoo]

Originally posted by: MercenaryForHire
I was thinking you meant boost pressure.

- M4H

Same here

 

[B00ne]

Originally posted by: holden j caufield
overinflating is bad for other parts of your car suspension, tire wear, etc.

However, slightly overinflating is much better than having too little pressure .

 

[DrPizza]

We got better mileage in our grand caravan by inflating the tires to a higher pressure. (IIRC, it was recommended that the tires be inflated at 28 or 29 psi; I put them at 34 for our long trip.