Good reference Car&Driver article effect of tire/wheel changes on mpg
Everyone interested in their mpg should read C&D's article on pg 32 of the latest issue. Well stated and we can attest to its validity.
Wider, heavier, larger diameter tires cut mpg and acceleration.
Uhhh, duh? Did it really take a whole article for them to point that out?
Its the proof that takes so long. Always is.
At my shop, even with 3 engineers on tap and a wall full of race trophies, a couple for mpg contests, we expected 90% of those customers wanting the biggest fattest tires that can fit in the fenderwell. And after being warned and their insisting, they always came back angry that their car wasn't as fast or got as good mpg as before. Some madder than heck. Didn't take long beforte the warning was included in the sales contract as a checked item they initialled. We believe that it reduced those come-backs by 90%.
Common sense rarely works with 'coolness' and competence beats cool every time. Don't believe it, go check some of the stuff touted on other car forums.
go check some of the stuff touted on other car forums.
Like how a bigger spoiler makes your car faster, and a cylcone intake gizmo provide +10 HP and +5 MPG. ...no thanks...
Good find with the article. I can imagine people with little common sense complaining about larger fatter tires hurting performance (other than improved grip) quite easily.
__________________
2002 Silver CVT w/ 105k miles... Here's to few more 100k's
61.3 ownership LMPG
Like how a bigger spoiler makes your car faster, and a cylcone intake gizmo provide +10 HP and +5 MPG. ...no thanks...
.
My favorite is the electric supercharger.Engineering calculations all show far more horsepower is needed to push a couple hundred cubic feet of air at 5 psig than any of those advertised can produce. We actually had a guy show up here with one and wanted us to see how much better it was on his Fit than normal. Compared to stock he was slower at high speed and considerably slower than a K&N type cone filtered one. At low speed possibly an improvement but not statistically proveable. Just seemed like it.
If you can't measure it with a stopwatch, (acceleration, speed, or lap time) or with quantity and distance as in mpg, and prove it statistically, it ain't better. Big sign over the competition office.
Everyone interested in their mpg should read C&D's article on pg 32 of the latest issue. Well stated and we can attest to its validity.
Wider, heavier, larger diameter tires cut mpg and acceleration.
I have not yet read the article, but a slightly taller (larger diameter) tire, by itself, should not necessarily reduce mileage. It depends on car weight and gearing among other things. Same effect as changing the ring and pinion to one slightly taller.
However, since most larger diameter tires also are wider and/or heavier, those factors will negatively affect mileage.
Regards,
Jerry
__________________
2004 MT Silver Bullet
West Palm Beach, Fl.
I have not yet read the article, but a slightly taller (larger diameter) tire, by itself, should not necessarily reduce mileage. It depends on car weight and gearing among other things. Same effect as changing the ring and pinion to one slightly taller.
However, since most larger diameter tires also are wider and/or heavier, those factors will negatively affect mileage.
Regards,
Jerry
The larger diameter tire would have to be much lighter to make up for the loss in force required to overcome centrifugal forces and we have seldom found a lighter tire unless the section is much reduced. Not easy with design 165 section tires.
Gearing etc is not a part of the consideration; its only for tire/wheel changes on a car that will not otherwise be modified.
The larger diameter tire would have to be much lighter to make up for the loss in force required to overcome centrifugal forces and we have seldom found a lighter tire unless the section is much reduced. Not easy with design 165 section tires.
Gearing etc is not a part of the consideration; its only for tire/wheel changes on a car that will not otherwise be modified.
If you are talking about insight tires (I thought the article was generic) I agree, the OE tires are the lightest ones around. Thre are similar tires with much better performance, but nothing lighter than the stock tires.
Which has always made me wonder how much of the insight's mileage is attributable to its low weight, small engine, IMA etc, and how much is attributable to the tires. Or stated another way, how much worse would the mileage be if the tires and wheels were swapped with say, the HCH from 03-05.
As to gearing, I said that a larger diameter (taller) tire has the same effect as changing the ring and pinion. So a 5% taller tire would have the same effect as a 5% taller diff (ring and pinion).
Regards,
Jerry
__________________
2004 MT Silver Bullet
West Palm Beach, Fl.
If you are talking about insight tires (I thought the article was generic) I agree, the OE tires are the lightest ones around. Thre are similar tires with much better performance, but nothing lighter than the stock tires.
Which has always made me wonder how much of the insight's mileage is attributable to its low weight, small engine, IMA etc, and how much is attributable to the tires. Or stated another way, how much worse would the mileage be if the tires and wheels were swapped with say, the HCH from 03-05.
Jerry
Bridgestone and Michelin say the ecotires add about 2 mpg to the ratings but at a loss in cornering power of about 5%.
And yes the article is generic, based on a Golf using 15, 16, 17,18 inch tires of close to the same diameter, but there are several lighter tires, especially the race-tire-for the street versions for SS racing.
As to gearing, I said that a larger diameter (taller) tire has the same effect as changing the ring and pinion. So a 5% taller tire would have the same effect as a 5% taller diff (ring and pinion).
Regards,
Jerry
After thinking a bit, I disagree, Changing the ring and pinion will change the engine rpm a few hundred rpm so the torque available won't change much. However, changing the tire diameter in an equal percentage will change the torque required by as much as the increased weight at larger radius, which will be a lot greater. I wouldn't expect the RAR change to affect mpg very much while a greater diameter tire will affect mpg a lot.
The AutoGuide.com network consists of the largest network of enthusiast-owned enthusiast-operated automotive communities.
AutoGuide.com provides the latest car reviews, auto show coverage, new car prices, and automotive news. The AutoGuide network operates more than 100 automotive forums where our users consult peers for shopping information and advice, and share opinions as a community.
Good reference Car&Driver article effect of tire/wheel changes on mpg
