Size of the tire - are smaller (narrower) tires really better?

[CargoBoatTails]

well I guess we'll never know for sure with the odometer error on different height tires.

[CapriRacer]

Originally Posted by CargoBoatTails

well I guess we'll never know for sure with the odometer error on different height tires.

Not exactly.

Many tire manufacturers will publish a Revolutions per mile value for their tires. Comparing those values between tire can give you a reasonably close value for the change in "geariing".

And just an FYI: There is no requirement that a tire be built to the dimensions given by the size designation. But most manufacturers do attempt to build tires to those dimensions. Just be aware that there are exceptions - usually because a vehicle manufacturer doesn't have enough room under the fenders for the "correctly sized" tire.

Also, the rolling diameter is about 97% of the freestanding diameter (the value usually published. If you do the math on any given tire, the published overall tire diameter is about 97% of the the value needed to get the Revs/mile.

[mcrews]

Originally Posted by CargoBoatTails

well I guess we'll never know for sure with the odometer error on different height tires.

1. that why we (ecomodder community) adhere to
REAL TESTING

weeds out the "i got XX mpg on this tank"

Real teasts account for the variables....
for example:
Using a gps to track miles instead of the odometer
doing the math to figure the correct differential in sizes
etc
etc
etc

You don't want to acknowledge that the world is not flat.

we have provided multiple sources of proof, yet you only come back with words, no proof.
PLEASE show me the gear ratios on the FX and the G, PLEAE proof you are right and not blind to truth and facts.

Much like your personal experience, where you don't compensate for the odometer being off or give the different weights of the tires and wheels.
You FAIL to give any factual information.

[niky]

Originally Posted by CargoBoatTails

well I guess we'll never know for sure with the odometer error on different height tires.

Odometer error doesn't come into play with the graph CapriRacer posted, since that's done on a bench.

It doesn't come into play with MetroMPG's tests, because those are measured by actual distance travelled measured on the ground, not from the on-board trip meter (if you have a trip meter that can measure in feet... good for you!)

And EPA tests are performed on a rolling road dyno... which means all speed and distance measures are audited by the machine, not the on-board odometer or speedometer.

_

It's simply this: Manufacturers themselves spec taller tires for the "high economy" variants of their cars. As shown by the Fiesta SFE. As shown by the Cruze Eco. They would not do this if those tires hurt economy. That is all.

[CargoBoatTails]

Well its funny all these lifted trucks running smaller tires because they get better gas mileage than the taller tires, but what do they know.

I did some due diligence and went looking for the narrowest tallest tires and this is what I came up with, narrowest first:

Nankang CX668 135/80R15 73T

Dunlop Enasave 01 A/S Passenger All-Season 145/65R15 LRR 72H

BFGoodrich Tires Radial T/A Spec P155/80R15 RWL 83S

Nankang Tires FT-7 FORTA A/T SL 175/80R16 BSW 91S

Bridgestone Tires ECOPIA EP02 P195/80R16 97S LRR

Continental 4x4 Contact 205/80R16C

Michelin LTX M/S2 LT215/85R16E LRR: Green X

That is about as narrow and tall as you're going to get from 22.4" to 30.4" with some good LRR models to cover most vehicles. I am interested to see a proper comparison with all the aforementioned calculations (ie GPS, Revs Per Mile%, ect.). Maybe even trying some motorcycle tires might do the trick lol.

[mcrews]

Originally Posted by CargoBoatTails

Well its funny all these lifted trucks running smaller tires because they get better gas mileage than the taller tires, but what do they know.

.

Again, PLEASE show the ABA tests and not a bunch of smart ass words



As I have stated on several occasions, when dealing with trucks, you have to start at the FACTORY size first. Not t the size currently on the truck.

It is hard to 'oversize' a car because suspension parts get in the way.
Trucks don't have that problem. So many posters just jump in and make a claim that is false.

But since you are unable to think beyond your mind set....

1. Did those OVERSIZED tires come from the factory???
2. did the owner put them on for better mpg????

As has been started in several tire posts, it is possible to put tooo much tire/wheel on and then you ruin the mpg.

But I bet you a dollar that when they put on the smaller tire it is NOT smaller than the factory tire.......which proves you to be 100% wrong in your assumption

also, most conversations on larger diameter deal with JUST THE TIRE and not going w/ a larger wheel.

SO ALLLLLL those jacked up trucks have larger WHEELS and tires. Not just larger tires.

Again this goes back to you ignoring the different rims you used in your tests.

[CargoBoatTails]

All I know is these guys and gals paid big money to jack up their tracks and just wanna run the stock tires bc they cant afford the gas lol so lets see some of these ABA tests you speak of bc I would much rather be a smart ass than a dumb ass bahahaha

[niky]

We've already posted the tests, the empirical data, the EPA ratings (granted, EPA is not always equivalent, but EPA tests for a SINGLE CAR LINE are done by the same manufacturer on a single rolling road with the same numbers) and everything else. You're the only one who doesn't get it.

Originally Posted by CargoBoatTails

I would much rather be a smart ass than a dumb ass bahahaha

Would help if you attempted not to be one, at all.

[Xist]

When I was in high school a friend told me that he modified cars into lowriders, installed hydraulics, etc. I asked why they put on small tires and he said they were lighter.

You are moving an entire car up, not just small wheels down!

[CapriRacer]

Here's the way this works:

When it comes to tires, there is a HUGE!!! range of rolling resistance WITHIN a given size - on the order of 60%. Time spent carefully selecting tires (meaning make and model) that fit your needs pays benefits.

By comparison, tire size by itself has a very small difference in RR - on the order of single digit percentage. So one would do well to research the tire (meanng make and model) rather than size.