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. tire width vs. drag (Cd) 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.