Wondering if 245/75/16 tires will give me better MPG that 265/70/16? Overall diameter is the same
Narrower tires give better MPG?
- Thread starter Bluestream
- Start date
If they have less rolling resistance, yes
The overall diameter is slightly taller (30.5 vs 29.6 inches) which will also cause your speedo to read slightly lower.
Depending on the tires you choose, your winter traction in deep snow will also be improved.
Depending on the tires you choose, your winter traction in deep snow will also be improved.
245/75R16 and 265/70R16 are essentially the same diameter ~30.5in
AZjeff
$50 Site Donor 2023
I made that exact change on the 02 xterra and see no difference in gas mileage. I hand calculate every fill-up.
"essentially" and "actually" are not the same concept.
There;s a 3.9% difference in diameter.
Look up up yourself
https://tiresize.com/comparison/
You calculated wrong and still have not realized, 245/75R16 is 30.5in, 265/70R16 are 30.6in.
Rolling resistance and wind resistance change, hard to know
depends on grip of tire, vehicle, operating conditions ect.
most cars and truck wont see a differrence but on highway only.
semis have super singles and they do diliver fuel saving over the life of tire on otr highway operation.
i did loss mpg (hand calculated), 95ish metro LSi, 1.0tbi and emissions on a china used turbo 1.0 long block so had a cam factory (hp not torque, no low end), lowest final ratio trans (4 gear cruiser around town, 5th was for 60+hwy), E10 87, 15k plug changes/timed, 13" rims, ect. was built ground up for hi-way mpgs.
long story short went from stock wide tires to wider tires with more grip, so more resistance. I lossed over 1mpg on the hi-way.
cant remember exact tire size, and mpg numbers, but i do remember lossing over 1 mpg, so lost 10+miles range per tank with wider more aggressive tires. but the loss was highway mpgs and city mpgs stayed about the same if i remember it was 15-16yrs ago.
-Harvey
most cars and truck wont see a differrence but on highway only.
semis have super singles and they do diliver fuel saving over the life of tire on otr highway operation.
i did loss mpg (hand calculated), 95ish metro LSi, 1.0tbi and emissions on a china used turbo 1.0 long block so had a cam factory (hp not torque, no low end), lowest final ratio trans (4 gear cruiser around town, 5th was for 60+hwy), E10 87, 15k plug changes/timed, 13" rims, ect. was built ground up for hi-way mpgs.
long story short went from stock wide tires to wider tires with more grip, so more resistance. I lossed over 1mpg on the hi-way.
cant remember exact tire size, and mpg numbers, but i do remember lossing over 1 mpg, so lost 10+miles range per tank with wider more aggressive tires. but the loss was highway mpgs and city mpgs stayed about the same if i remember it was 15-16yrs ago.
-Harvey
Almost exactly what I did with my 4Runner and the rolling resistance is noticeably less, the 265/70/16 is a Big-O Bigfoot all-terrain tire, the 245/75/16 are Hankook Dynapro HT Highway Light Truck Tire. In this example the MPG is better, I just couldn't give you an exact figure, and the slightly exaggerated example I use for handling is like going from driving a tractor to driving a Camry.
regardless, .3% is still not the same.
For the purposes of a speedo, it's not enough difference, your speedometer doesn't know how much tread depth you have, after a little tread wear the 265/70R16 tire will be no different than a new 245/75R16, .3% is close enough for the OPs question, it'd be close enough for a staggered wheel arrangement, the only place it wouldn't be close enough is if you're running them on the same axle, but then again I don't see why anyone would ever run a different width tire on the same axle unless it's a spare and it's used the way a spare is supposed to be.
I have gone wider several times, keeping essentially the same diameter, and my mileage has always decreased when doing so. By that thinking, were i to revert to skinnier oem sizing, mpg would return to its original, higher number.
my guess is that a wider tire has more material flexing on both the leading edge and trailing edge of the contact patch, so if you’re talking about two tires of the same material and construction, theoretically the skinnier one requires less material to flex during rotation. Wind resistance is also a thing that counts.
snow traction and hydroplaning resistance also improves with narrower tires, as well.
my guess is that a wider tire has more material flexing on both the leading edge and trailing edge of the contact patch, so if you’re talking about two tires of the same material and construction, theoretically the skinnier one requires less material to flex during rotation. Wind resistance is also a thing that counts.
snow traction and hydroplaning resistance also improves with narrower tires, as well.
