joedoe

Recently replaced 215/60/16 all season touring tires with 225/55/16 ultra high performance summer tires and lost about a mile per gallon. Is it how it supposed to be?

bravo261

iTrader: (1)

tires aren't that different to really change mpg by a mile. no expert, but you sure it wasn't just driving conditions or measuring inaccuracies? like the nav, i don't trust that mpg thing too much

strongsail

I recently went from stock 225/55-16s to 235/45-17 fronts and 255/45-17 rears on my SC4, and my gas mileage has dropped substantially - from about 23 highway to about 20, or about 10%. Much larger contact patch, more rolling resistance, it only makes sense that you lose efficiency when you gain traction and handling. I have a long road trip coming up later this month, will get a better idea of highway mileage, will post the numbers when I get back -

///MDex

...what I was going to say...

joedoe

That what I thought too.

squarehat

Specification Sidewall Radius Diameter Circumference Revs/Mile Difference
215/60-16 5.1in 13.1in 26.2in 82.2in 771 0.0%
225/55-16 4.9in 12.9in 25.7in 80.9in 783 -1.6%


The new tires are slightly smaller in outside diameter, not sure of the effects on gearing and speedometer.

strongsail

if the new tires are slightly smaller, hence more revs/mile, speedo and odo will be off a bit, that's true too.

So, will I go back to perching on my oem wagon wheels to get better mileage?

Not likely

joedoe

Yeah, actually speedometer and odometer are 1.7% off now.

bitkahuna

iTrader: (20)

1mph at 60 - big whoop.

As far as mpg, ya gotta pay to play.