Taller tires = better MPG?

[BeoWolfe]

Greetings,

I had a question for you MPG folks. I have a manual transmission car that runs over 3k RPM when I am going 75mph (I drive 180 miles a day on the highway). Would changing to a taller tire lower my RMPs and give me better MPG?

[diamondlarry]

Originally Posted by BeoWolfe

Greetings,

I had a question for you MPG folks. I have a manual transmission car that runs over 3k RPM when I am going 75mph (I drive 180 miles a day on the highway). Would changing to a taller tire lower my RMPs and give me better MPG?

It could give slightly better mileage. The only drawback would be that your odometer/speedometer would be off.

[Hockey4mnhs]

i would think not because there is probly more tire hiting the ground

[thisisntjared]

Originally Posted by diamondlarry

The only drawback would be that your odometer/speedometer would be off.

exactly, so you wouldnt really know if you were getting better mpg. narrower (lower rolling resistance) tires are better for fuel economy.

[LxMike]

They would lower your rpm's somewhat and that in theory shoudl help with milega ebut would be a small change. unless you get tires 2-3" taller

[MetroMPG]

unless you get tires 2-3" taller

Which would of course make aerodynamics worse, possibly cancelling the benefit of lower engine RPM (Of course you could try to go taller, but narrower...)

Dropping my engine RPM by 25% with the transmission swap, I got a 5% increase in MPG in top gear.

[SVOboy]

Tell us more about the car and we can prolly give you better suggestions. I vote for aero mods at this point.

[thisisntjared]

Originally Posted by SVOboy

I vote for aero mods at this point.

i agree but i think it depends more on the type of driving done than the car...

[SVOboy]

Originally Posted by thisisntjared

i agree but i think it depends more on the type of driving done than the car...

He said 75mph 180 miles a day.

[Sludgy]

Narrower tires of the same height would provide a definite aero improvement. Go with a low rolling resistance brand, and inflate to the maximum sidewall rating. Did he say what size tire he's running?