Tire Width vs Circumfrence = Rolling Resistance

[DRaider90]

I have been wondering which effects the rolling resistance of a tire more? The width? Or the circumference (aka Height)? Or do they have an equal effect? I have read up on this and found a few debates on some sports car forums, but nothing concrete.

Reason I am asking is I am looking to move up to a 1.6" Narrower Tire, but 1.8" larger in height. And I will also mention the larger but narrower tires are only 5 pounds heavier. Because my hopes in all this is that the tires being 1.6" Narrower will almost cancel out the effects of them being 1.8" bigger in height. This won't be true though if say height effects rolling resistance more than width.

Any thoughts on this? And to those saying approx 2" isn't that big of a deal in tire size, yes it is when you are running a carb'd 2.6 four banger. Especially when you are all ready running 34"s on it, when it came with 28"s stock. And no funds are not currently available to upgrade the engine. But yes I will be moving up from 4.62s to 4.88s to help with the increase from 34"s to 36"s essentially.

(And for those wondering we are comparing 33.7x12.4-15 TSLs to 35.5x10.8 TSLs)

 

[4LWranglerTJ]

Good question but isn't 1.8 inches in height more like 5.65 inches in the circumference?
My guess is that the height would not affect rolling friction since the footprint of the tire at any given point is mostly determined by the width. The wider the tire, the larger the footprint right? Now larger tires would cause losses in the drivetrain since they are heavier and require more torque to turn them and they have more air resistance. That is my stab at answering the question. I really dont know if it is right though and hell, it's 2:20am so I am off to bed.

 

[shawn]

Tread pattern makes the biggest difference.

The Michelin XZL used to have one of the lowest rolling resistances of any tire around... low enough that it was actually used on cars in efficiency competitions.

And those fawkers are not small or light.

However, in your case you should be more concerned about the diameter of the tire compared to your diff gearing. The two tires you've listed aren't different enough to change much. It'll be a dog, but not much worse than it was before.

 

[Ron]

The tread width/contact area will determine your coefficient of friction, but so will the tread pattern and compound and driving surface.

 

[jeepinmatt]

The biggest thing to help with rolling resistance is to keep them inflated to whatever the max inflation rating is, regardless of the type of tire. However, you are fighting a battle with rotational inertia, and going to a bigger tire, you will lose.