R56 Tires
2nd Gear
Joined: Sep 2003
Posts: 140
Likes: 0
From: Brea, CA
The Rim size difference from 16" to 17" should make no difference if the circumference of the tire is the same. The thing most likely to impact fuel mileage is the weight of the wheel plus tire.
Lighter is easier to turn, thus should require less power.
Lighter is easier to turn, thus should require less power.
6th Gear
Joined: Mar 2007
Posts: 7,578
Likes: 5
From: Paradise
If you are talking about OEM tires, the 16" are narrower. All other things being equal, that would give better mileage.
I think you also have to compare the revolutions per mile, and the rolling resistance of the tires in question to answer that. Dunlap Sport 01 DSST runflats have the same revs. per mile in 16" & 17" sizes. So, you would have to find the rolling resistance for each tire to know for sure. If they are about equal, the 16" should get better mpg.
I think you also have to compare the revolutions per mile, and the rolling resistance of the tires in question to answer that. Dunlap Sport 01 DSST runflats have the same revs. per mile in 16" & 17" sizes. So, you would have to find the rolling resistance for each tire to know for sure. If they are about equal, the 16" should get better mpg.
6th Gear
Joined: Aug 2006
Posts: 1,762
Likes: 0
Well here's my semi-educated guess:
No.
...and here's why: Wheels sizes (17 vs. 16) usually keep the same overall tire diameter. If the overall tire diameter changes (specifically gets larger) you will see an increase in milage just as if you went to an ever-so-slightly hight gear ratio.
Another thing that occurres with switching from the 16 (195/55-16) to the 17 (205/45-17) is that you increase the width of the tire. Increased width provides an increased contact patch on the roadway. An increased contact patch creates better grip... but also adds rolling friction or rolling resistance. Increased rolling resistance means decreased gas milage.
My guess therefore is that the ever-so-slight difference in diameter will be cancelled out by the increased rolling resistance of the wider tire.
Granted, I think both of these gains or losses probably equate to less than 1-2% of real world fuel economy... so hardly measureable IMO.
So get whichever wheels you lke better and keep them properly inflated (as that probably has more of an effect on milage and tirewear in the long run).
Like I said... just a semi-educated guess. Someone could come along and school me here shortly, too.
No.
...and here's why: Wheels sizes (17 vs. 16) usually keep the same overall tire diameter. If the overall tire diameter changes (specifically gets larger) you will see an increase in milage just as if you went to an ever-so-slightly hight gear ratio.
Another thing that occurres with switching from the 16 (195/55-16) to the 17 (205/45-17) is that you increase the width of the tire. Increased width provides an increased contact patch on the roadway. An increased contact patch creates better grip... but also adds rolling friction or rolling resistance. Increased rolling resistance means decreased gas milage.
My guess therefore is that the ever-so-slight difference in diameter will be cancelled out by the increased rolling resistance of the wider tire.
Granted, I think both of these gains or losses probably equate to less than 1-2% of real world fuel economy... so hardly measureable IMO.
So get whichever wheels you lke better and keep them properly inflated (as that probably has more of an effect on milage and tirewear in the long run).
Like I said... just a semi-educated guess. Someone could come along and school me here shortly, too.
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