Does size of tires effect MPG?
#1
Does size of tires effect MPG?
I believe the 2008-2009 Ford Escape Hybrids come with 17 inch wheels right, but what if I were to put 18 inch rims on?
Could that actually add MPG since an extra inch of tire would cover more ground? Has anyone added a bigger tire and what were the results?
super
Could that actually add MPG since an extra inch of tire would cover more ground? Has anyone added a bigger tire and what were the results?
super
#2
Re: Does size of tires effect MPG?
Your thoughts are in the right arena, however the sidewall height of an 18" tire is usually lower, making the overall circumference about the same as a 16" or 17" tire wheel combination.
In order to accomplish what you desire, you can replace your 16" tires with bigger 16"tires - with an inch or two of additional circumference - ie. taller sidewall.
Most (perhaps all?) FEH's come with 235/70-16" tires. 235 represents the millimeters across the width of the tire. 70 means that the heigth of the tire (rim to tread) is 70% of the tire width, and the 16" represents the rim diameter.
You could increase the circumference of the tire by installing 235/75-16 tires. There are limits on the size tire you can put on your vehicle however. If you go too big, you may rub the inner fender or other suspension/steering components.
Since the Ford engineers leave a little extra room (assuming some customers will install slightly larger snow tires), I would guess another 3/4 inch in diameter (2 1/2" in circumference) would be close to the upper safe size limit. That would represent a 3% "overdrive".
I doubt your fuel economy would improve by 3% since there are other factors involved, but you might pick up 2%. (Rembering that 100 miles on the odometer actually represents about 103 miles and 60 miles per hour is actually 62 miles per hour.)
In order to accomplish what you desire, you can replace your 16" tires with bigger 16"tires - with an inch or two of additional circumference - ie. taller sidewall.
Most (perhaps all?) FEH's come with 235/70-16" tires. 235 represents the millimeters across the width of the tire. 70 means that the heigth of the tire (rim to tread) is 70% of the tire width, and the 16" represents the rim diameter.
You could increase the circumference of the tire by installing 235/75-16 tires. There are limits on the size tire you can put on your vehicle however. If you go too big, you may rub the inner fender or other suspension/steering components.
Since the Ford engineers leave a little extra room (assuming some customers will install slightly larger snow tires), I would guess another 3/4 inch in diameter (2 1/2" in circumference) would be close to the upper safe size limit. That would represent a 3% "overdrive".
I doubt your fuel economy would improve by 3% since there are other factors involved, but you might pick up 2%. (Rembering that 100 miles on the odometer actually represents about 103 miles and 60 miles per hour is actually 62 miles per hour.)
Last edited by Red; 09-13-2008 at 04:13 PM.
#3
Re: Does size of tires effect MPG?
After reading about information on tires and rims for the FEH, the lighter FEH rim with the lighter weight Michelins are the best possible combination for mileage. You can find the weights and more information in a tread I started a few months ago:
http://www.hybridcars.com/forums/tires-and-rims.html
GaryG
#4
Re: Does size of tires effect MPG?
This is a copy of John Morton's signature:
he actually changed the size of his tires for his 2006 FEH. He claims very positive results (compared to stock ECO-Plus tires) in all areas but mileage.
18"x 8" OZ Canyon wheels/Bridgestone Dueler H/L Alenza (255/55R-18) tires.
This is a link to his site and photos:
http://www.pbase.com/jmorton10/inbox&page=all
he actually changed the size of his tires for his 2006 FEH. He claims very positive results (compared to stock ECO-Plus tires) in all areas but mileage.
18"x 8" OZ Canyon wheels/Bridgestone Dueler H/L Alenza (255/55R-18) tires.
This is a link to his site and photos:
http://www.pbase.com/jmorton10/inbox&page=all
#5
Re: Does size of tires effect MPG?
Tire diameter for stock =16+(2*235*.7/25.4)=29.0"
John Morton's tires =18+(2*255*.55/25.4)=29.0"
If your #rotations/mile is off by too much, you'll get a MIL.
John Morton's tires =18+(2*255*.55/25.4)=29.0"
If your #rotations/mile is off by too much, you'll get a MIL.
#6
Re: Does size of tires effect MPG?
oh yea, and I found some rims I like that are also 18X8 , how much do you think that will effect MPG?
A lot, or just a little?
thanks
super
Last edited by superserial; 09-14-2008 at 11:01 PM. Reason: adding
#7
Re: Does size of tires effect MPG?
This is a copy of John Morton's signature:
he actually changed the size of his tires for his 2006 FEH. He claims very positive results (compared to stock ECO-Plus tires) in all areas but mileage.
18"x 8" OZ Canyon wheels/Bridgestone Dueler H/L Alenza (255/55R-18) tires.
This is a link to his site and photos:
http://www.pbase.com/jmorton10/inbox&page=all
he actually changed the size of his tires for his 2006 FEH. He claims very positive results (compared to stock ECO-Plus tires) in all areas but mileage.
18"x 8" OZ Canyon wheels/Bridgestone Dueler H/L Alenza (255/55R-18) tires.
This is a link to his site and photos:
http://www.pbase.com/jmorton10/inbox&page=all
thanks
super
Last edited by superserial; 09-14-2008 at 11:02 PM.
#8
Re: Does size of tires effect MPG?
This is a copy of John Morton's signature:
he actually changed the size of his tires for his 2006 FEH. He claims very positive results (compared to stock ECO-Plus tires) in all areas but mileage.
18"x 8" OZ Canyon wheels/Bridgestone Dueler H/L Alenza (255/55R-18) tires.
This is a link to his site and photos:
http://www.pbase.com/jmorton10/inbox&page=all
he actually changed the size of his tires for his 2006 FEH. He claims very positive results (compared to stock ECO-Plus tires) in all areas but mileage.
18"x 8" OZ Canyon wheels/Bridgestone Dueler H/L Alenza (255/55R-18) tires.
This is a link to his site and photos:
http://www.pbase.com/jmorton10/inbox&page=all
oh yea, did he state how many MPG he was getting on those 18 inch wheels?
#9
Re: Does size of tires effect MPG?
Oh, I didn't realize you were looking at 18X8 wheels. Since 18X8 =144 and the sq.root of 144 is 12, you should expect a 12% increase in fuel economy.
I hope this helps, since I obviously wasted my time on my earlier post.
I hope this helps, since I obviously wasted my time on my earlier post.
#10
Re: Does size of tires effect MPG?
EXCUUUUSE MEEEEEE for wanting to get another opinion
super