Thinner width tire for improved mpg

[Floordford]

For the past two or so hours ive been reading all the ins and outs of low rolling resistance tires. From what I dug up the cost seems to even itself out. The extra money you spend on them will just pay for the bonus of using them. So I don't see any real gain.

BUT

people on here talk about taller tires but I havent seen any threads started about getting tires that are thinner. Example: my Mustang has 245/45/R17 stock. I could go to a 235 or I could push it with a 225. If I ran the PSI higher as I normally would id be making even less contact with the ground with the 235 than I would with the 245. Or for a car with 195/60/R15 use a 185/65/R15. I think this might be a benefit only if the thinner tires costed less or the same. Probably not worth it if they cost more.

[CapriRacer]

Smithers Scientific Services conducted a whole bunch of tire tests for the califonia Energy Commission. I summarize the presentation here:

Barry's Tire Tech

About half way down, I discuss the size study and develop a formula based on the data.

RRC = 0.00246493 - 0.00000208*(Section Width in mm) - 0.00000386*(Aspect Ratio in whole numbers) - 0.00004700*(Rim Diameter in inches)

Short version: Bigger is better.

[Floordford]

Interesting stuff. Im glad you responded instead of someone else trying to make sense of a long article like that. From what I gather a wider tire can be ran at a higher pressure. And its more efficient because it can spread the load better. Is that right?

I tried to keep up with this thread but there was a massive amount of info. And just as I thought one line of thought was right another person would chime in and tear it apart. http://ecomodder.com/forum/showthrea...cd-7475-2.html But that was mostly about aero drag vs tire size.

[Big Dave]

Narrower tires make effective wheel skirts easier to do.

[astroturf]

Why not buy the best Low Rolling Resistance Tires?

www dot nokiantires dot com

Jim

PS I only have 4 posts and cannot attach the proper link. I'm sorry. I will work on getting my post count up. LOLz, Jim

[Floordford]

Originally Posted by astroturf

Why not buy the best Low Rolling Resistance Tires?

www dot nokiantires dot com

Jim

PS I only have 4 posts and cannot attach the proper link. I'm sorry. I will work on getting my post count up. LOLz, Jim

I mentioned those in the first four sentences of the first post.

[astroturf]

Originally Posted by Floordford

I mentioned those in the first four sentences of the first post.

Huh, I didn't see any mention of the Nokian eNtyre in your first post...

Sorry, Jim

[jamesqf]

Originally Posted by CapriRacer

Short version: Bigger is better.

I find it very surprising that increasing width would decrease rolling resistance. I sure see the opposite effect on the only experiment I can conduct: road bike vs mountain bike. I run a fairly smooth road-type tread on the MB, and inflate them to their max pressure, yet it takes perceptibly more effort to maintain a given speed than with the skinny-tired road bike.

[CapriRacer]

Originally Posted by jamesqf

I find it very surprising that increasing width would decrease rolling resistance. I sure see the opposite effect on the only experiment I can conduct: road bike vs mountain bike. I run a fairly smooth road-type tread on the MB, and inflate them to their max pressure, yet it takes perceptibly more effort to maintain a given speed than with the skinny-tired road bike.

The problem is apples and oranges:

Did you use the same inflation pressure?

Are the tires otherwise identical?

That's what makes that study so valuable - those things were the same.

[Floordford]

Originally Posted by astroturf

Huh, I didn't see any mention of the Nokian eNtyre in your first post...

Sorry, Jim

You mentioned low rolling resistance tires, which is what I mentioned. There is no way I could have mentioned specifically every single last tire that is deemed a low rolling resistance tire.