Tire pressure?

[BailOut]

Increasing tire pressure increases handling, traction and tread life as well as mileage. I run mine at 60 PSI, as do thousands of other hypermilers.

Originally Posted by YAR1S

Besides... from what I've heard the differnce isnt much... give or take a few miles, right?

Fuel efficiency is all about many tactics adding up to significant gains. Tire pressure is one of the larger factors.

[YarisSedan]

=>

[YarisSedan]

I think the max for a small passanger car tire is 50psi tops. Also the reason why you get better gas milage is becuase now you have less tire to pavement contanct resulting in less rolling resistance. But in turn you will wear out the center of your tire very quickly. There is also a reduction in traction after you get past a certain point of overinflation. Which randomly guessing would be around 45. As well as greater chance of damage to the tire from potholes and road debri. Also depending on the weather climate where you live and the speeds you are going the heat will cause the air in the tire to expand by a few more pounds. Just like when youloose a few pounds of air in colder climate. This could result in psi ranges of 65. Only tires i know that are meant to be run at those raitings are the huge truck tires.

If you want to get the best economy with handling inprovements without and risk or increased wear on tire i would set it around 40. But definately not in the 60s.

[PreciousPups4U]

Mine are around 40 - 42 psi. That rides best to me. Not sure how it affects mpg, it's just what's comfortable to me. I can really tell when they get low.

[*MAD DOG*]

Originally Posted by BailOut

Increasing tire pressure increases handling, traction and tread life as well as mileage. I run mine at 60 PSI, as do thousands of other hypermilers.

Fuel efficiency is all about many tactics adding up to significant gains. Tire pressure is one of the larger factors.

Too high. You'll have a blowout on a hot day. Your tires are a ticking timebomb.

Originally Posted by PreciousPups4U

Mine are around 40 - 42 psi. That rides best to me. Not sure how it affects mpg, it's just what's comfortable to me. I can really tell when they get low.

That's what I run mine at and that is the maximum the handbook recommends. I feel that 40-42 psi is perfect.

[4MPG]

Originally Posted by BailOut

Increasing tire pressure increases handling, traction and tread life as well as mileage. I run mine at 60 PSI, as do thousands of other hypermilers.




Fuel efficiency is all about many tactics adding up to significant gains. Tire pressure is one of the larger factors.

more pressure may increase mileage, but it sure as hell doesn't increase handling/traction or tire life.

your getting better mpg because you have less tire contact on the road (less resistance) and less flex (wasted energy). However, this also results in less traction and poorer handling. It will also reduce tire life by wearing the center tread faster, since it takes all the wear instead of spreading it over the entire tire... you will get a bald center with tread still on the sides. You can see a picture of this at almost any tire store, as they usually have them posted up along with the reason for it happening and what causes it etc. While overinflation might result in a drop in tire temp, the center wear will outweigh any benefit.

If you want even more proof, especially on the traction side, visit any local dragstrip. You will see all of the "street" cars lowering tire pressure after they arrive, and almost any dragstrip worth its salt has a compressor so you can bring them back to road pressure before you leave. The drag radials on my mustang are particularly sensitive to tire pressure, going from 25 to 20 PSI resulted in nearly a .2 second faster 60' time. Even on my buddies T/A, with stock goodyear regular radials, he was regularly picking up .1 in the 60' with a 5-8 PSI drop from his street pressure.

For traction, and to a lesser degree handling (gotta keep the pressure up enough to keep the sidewall fairly stiff) you want a lower than standard pressure, not higher. You want as much resistance as possible, as resistance is what gives you traction/handling, and to achieve this you get as much contact patch as you can. The basic idea is to lower the pressure to the point that you have as much of the outer part of the tire in contact as possible, without causing the center section to actually start rising from the road (too underinflated).

Edit: To answer the poster above me, to get maximum tire life your probably going to want to run your tires a few (3-5) PSI higher than the doorjam recommends. The doorjam takes into account the best PSI for the tire, but it also takes into account that a lower pressure will result in a better ride (soaks up more vibration/bumps etc).

[50MPGDream]

over 22,000 miles logged on the stock tires at 50 PSI

and for the record, i once had a blowout in my camaro on a tire that was less than a week old with the PSI at 32... not all blowouts are related to PSI, and I think it's safe to say that it had nothing to do with the PSI but more to do with whatever was on the road that poked the hole in the tire

Originally Posted by 4MPG

If you want even more proof, especially on the traction side, visit any local dragstrip. You will see all of the "street" cars lowering tire pressure after they arrive, and almost any dragstrip worth its salt has a compressor so you can bring them back to road pressure before you leave. The drag radials on my mustang are particularly sensitive to tire pressure, going from 25 to 20 PSI resulted in nearly a .2 second faster 60' time. Even on my buddies T/A, with stock goodyear regular radials, he was regularly picking up .1 in the 60' with a 5-8 PSI drop from his street pressure.

My camaro's best 60' time (1.8xx) came on a set of drag radials at 20 PSI, but that relates to MPG in no way (I'm sure I was using more than a gallon per mile in those 60 feet)