Tires and FE ?'s

[nubbzcummins]

My current tires are 325/55/22 and weigh 68lbs each and are 36.1" tall on a 55lb wheel. So Tire/wheel combo is ~123lbs each. I'm wanting to go to a 305/45/22 in the same tire which weigh 50lbs each and are 32.8" tall. This will save me 18lbs or 17.1% in rotational weight for each tire/wheel combo but will affect my overall drive ratio by 10%. Also the later tire will have less frontal area being shorter and slightly narrower. I drive 90% highway and 10% city through slow rolling hills. How should this affect my FE?

[Frank Lee]

This is a trick question right?

[MadisonMPG]

Originally Posted by Frank Lee

This is a trick question right?

loled


To answer question, yes it will. How much? I don't know.

[CapriRacer]

Originally Posted by nubbzcummins

My current tires are 325/55/22 and weigh 68lbs each and are 36.1" tall on a 55lb wheel. So Tire/wheel combo is ~123lbs each. I'm wanting to go to a 305/45/22 in the same tire which weigh 50lbs each and are 32.8" tall. This will save me 18lbs or 17.1% in rotational weight for each tire/wheel combo but will affect my overall drive ratio by 10%. Also the later tire will have less frontal area being shorter and slightly narrower. I drive 90% highway and 10% city through slow rolling hills. How should this affect my FE?

Steady State FE is actually going to be worse and the only thing that will be better will be stop and go driving. When it comes to tires, because they are pretty much covered by the fenders, aerodynamics hardly plays a role.

That means for the 90% highway driving you do, this is the wrong direction. However, the 10% city will improve somewhat.

You would have been further ahead to buy smaller diameter wheels and high aspect ratio tires.