fuel savings 165/80/r14 175/70/r14

[somerandomguy1]

Good morning,

I would like to know roughly how much fuel would i save from going from a 175/70/r14 tire to a 165/80/r14 tire?

thanks

 

[Danh]

Nothing. But as the 165/80 tire is about 19mm greater in diameter your odometer would show you travelled fewer miles than the same route with the 175/70, so you would think economy decreased. Keep in mind the speedometer and odometer gauge speed and distance on wheel revolutions.

 

[Jetronic]

nothing measurable, you might even lose mileage.

 

[somerandomguy1]

for which size tires is the odometer on 1990 toyota corolla sedan 1.8 diesel calibrated for? 13?
i am running 14, does that affect the odometer like you said in some way?

why would there be no fuel savings?, if 165 is skinnier tire and has less contact patch with road so less rolling resistance better fuel economy?

why would i lose mileage?

 

[Jetronic]

The rolling resistance comes from the deformation of sidewalls and thread. There could be more deformation with the narrower tyre

 

[kschachn]

for which size tires is the odometer on 1990 toyota corolla sedan 1.8 diesel calibrated for? 13?
i am running 14, does that affect the odometer like you said in some way?

why would there be no fuel savings?, if 165 is skinnier tire and has less contact patch with road so less rolling resistance better fuel economy?

why would i lose mileage?

That isn't the only factor.

As for what size the speedometer is calibrated for, it would be the size(s) on the tire placard. The size the car was delivered with.

 

[bullwinkle]

You won't know until you try it, and correct for odometer errors. The highest PSI you can stand, up to sidewall pressure, will also help slightly. If your old tires were worn down, and the new ones have a lot of tread, tread squirm may eat up the savings!

 

[Quattro Pete]

why would there be no fuel savings?, if 165 is skinnier tire and has less contact patch with road so less rolling resistance better fuel economy?

The shape of the contact patch changes, but the overall area of that contact patch may not change much.

If you're looking for noticeable fuel economy improvements, you're looking in the wrong place, IMO.

Adjust your driving habits, combine your trips, air up your tires, make sure your vehicle is in good overall working condition.

Also, specific tire brand/model may have larger impact on fuel economy than going from 175 to 165 width.

 

[somerandomguy1]

the 175 are champiro vp1 and the 165 width are highfly hf201

 

[FordMan59]

The 165/80-14 is 3.2% larger which will give you taller gearing which will slightly decrease RPM's and probably give a slight improvement. I used to run tires as large as 185/75/14 on an '88 Escort that came from the factory with 165/80/13. That was an increase of 6.5% in tire size and I saw a couple MPG increase.

 

[tasch72]

The 165/80 tires would revolve 26 less times per mile than the 175/70 tire.

With the 165/80 tires, your speedometer would also be off by 2mph at 60 mph, so when your speedo would read 60, you'd actually be travelling at 62 mph.

At most we're looking at a 1-2 mpg difference because you won't need to rev the car up as high to achieve the same travel speed, assuming all other variables are constant.

Now, over the life of the tires, that could add up, but would the decrease in contact patch be worth it?

 

[somerandomguy1]

https://www.1010tires.com/ says the stock tire for the 1990 toyota corolla sedan was 155/80/r14, meaning the odometer was calibrated for this size.

so running a 175 70 14 tire would mean that i would of actually traveled around 3.76% more distance than what the odometer says since larger diameter tires cover more distance than smaller diameter tires per revolution.

https://www.tyresizecalculator.com/tyre-wheel-calculators/tire-size-calculator-tire-dimensions says that 165/80r14 revs 16 times less than 175/70/r14.

Would most of the fuel efficiency from the 165/80r14 tires be from the fact that it has a larger circunference and the engine revs less or from the 10mm less in contact patch?

what does a decrease in contact patch do?

 

[Quattro Pete]

https://www.1010tires.com/ says the stock tire for the 1990 toyota corolla sedan was 155/80/r14, meaning the odometer was calibrated for this size.

so running a 175 70 14 tire would mean that i would of actually traveled around 3.76% more distance than what the odometer says since larger diameter tires cover more distance than smaller diameter tires per revolution.

I think you meant 155/80/13, not 14.

Anyway, the 175/70/14 whee/tire combo is probably also heavier, which means more fuel wasted when accelerating, so it may be a wash, at least in city driving.

 

[bullwinkle]

https://www.1010tires.com/ says the stock tire for the 1990 toyota corolla sedan was 155/80/r14, meaning the odometer was calibrated for this size.

so running a 175 70 14 tire would mean that i would of actually traveled around 3.76% more distance than what the odometer says since larger diameter tires cover more distance than smaller diameter tires per revolution.

https://www.tyresizecalculator.com/tyre-wheel-calculators/tire-size-calculator-tire-dimensions says that 165/80r14 revs 16 times less than 175/70/r14.

Would most of the fuel efficiency from the 165/80r14 tires be from the fact that it has a larger circunference and the engine revs less or from the 10mm less in contact patch?

what does a decrease in contact patch do?

Smaller patch means better traction in snow, slightly worse in dry, possibly slightly better in rain. I wouldn't change sizes for the heck of it, but if your old ones are worn out, & the new ones are dirt cheap (Highfly better be, sounds ChInese), it might be OK. I'm personally running 14 inch 70 profile snow tires on Civic wheels on the xB, speedo is more accurate with the 185/70R14s than the factory 185/60R15s, and they clear everything fine.

 

[Danh]

for which size tires is the odometer on 1990 toyota corolla sedan 1.8 diesel calibrated for? 13?
i am running 14, does that affect the odometer like you said in some way?

why would there be no fuel savings?, if 165 is skinnier tire and has less contact patch with road so less rolling resistance better fuel economy?

why would i lose mileage?

The contact patch will.be the same size, albeit with a slightly different shape. And the difference in wind resistance with this slightly narrower tire is absolutely insignificant in relation to the total.

 

[somerandomguy1]

Sorry. I meant that that 10tires website says stock tire size 155/80/r13.

Champiro is also chinese. The champiros go for around 39 dollar a tire and the highfly 51 dollar a tire.

Which is the most fuel efficient tire in size 14 rim?

Fuel efficiency competitions feature vehicles with narrow and tall tires.

 

[Pew]

I would say negligible. I doubt the fuel savings you may save cruising on the highway won't really be beneficial or noticeable.

 

[CapriRacer]

The difference between tires in different sizes - all other things being equal - is small compared to the differences between make and models (up to 60%)

So you should concentrate on the make and model first, before you tackle the size thing.

But to answer your question, a 165/80R14 is 1.5% better for RR than a 175/70R14, but I doubt you can fit a 165/80R14 under the fenders of a Corolla.

But the above doesn't take into account the affect the rolling diameter will have on engine performance. I don't think you can quantify that to any degree of precision, especially given that we don't know how you use the vehicle. Lots of stop and go driving consumes a lot of fuel compared to the distance traveled, so any improvement a different tire will give you is going to be small compared to the weight being accelerated.

Also, you've posted a similar question at Ecomodder.com - but with different sizes.

 

[somerandomguy1]

Which nooneone has answered on ecomodder.com

As far i inderstand the taller the tire the more fuelefficient for highway driving and the smaller the tire the more edficient city driving.

How is a 165/80/r14 1.5 % better for rr?

How would i concentrate on the make and model difference?

165/80r14 fits on a corolla. I have one on the left rear tire. If these are the most fuel efficient i would like to place the on all 4 tires.

Here are pics of the the 165/80r14

Tread plies are 1 polyester and 3 steel
And sidewall ply is 1 polyester

 

[kschachn]

Fuel efficiency among tires is a complicated technology. Somehow I don't think cheap Chinese tire companies have invested the R&D to accomplish what's required to be the "most" fuel efficient as you keep asking.

If you insist on buying cheap Chinese tires perhaps your cost savings will more than offset the fuel usage differential compared to a more expensive tire that advertises less consumption.

https://www.nhtsa.gov/sites/nhtsa.dot.gov/files/fmvss/Label_Examples.pdf