Taller Tires Don't Get You As Bad Gas Mileage As You Think?

[LINY4Runner]

The surface area of a tire does not influence its friction on the road, It remains the same regardless of its width.

Weight does play a role in the amount of friction present between 2 surfaces.

I never said it increases the friction on the road. I said drag. As in a wider tire will catch more air than a skinny tire. Granted, it's not a HUGE difference in gas mileeage, it does make a difference.

 

[LINY4Runner]

It's commonly thought to be more rolling resistance.. Care to share your theory as why? I know bicylists use skinner tires when doing anything other than moutainbiking let's just say road use because of less rolling resistance..

I'm a cyclist. The skinnier tires slice through the air better than wide knobby tires, which is why my road bike is capable of 50+mph and a mountain bike isn't. We also inflate them to 100psi...wanna guess why? Smaller contact patch=less resistance=faster times.

I understand you're reading from a textbook, but this is a slightly different scenario

 

[CJ3Flyr]

Good thoughts, but you cannot defy physics. Bigger tires usually mean more weight, especially further away from the center. It WILL take more power to turn, which means more gas. Width doesn't matter as much (to an extent). For instance, I went from 265/70/16's to 235/85/16's and noticed a 1-2MPG drop. It is better than when I had 265/75/16's (2-3MPG drop), but it still DROPPED. Simply, it will take more power to turn those tires. (And BTW, the miles driven were all calibrated accordingly.) You can change the gearing to compensate, but you will still see a drop in MPG.

Really I wouldn't have guessed better mpg w/265/70's over 235/85's. What pressure do you run in 235/85's? Just curious as I have contemplated the 235/80/17 size for mine. (I'll probably settle on the 255/75/17.)

Thanks,
:cheers:

 

[p nut]

Really I wouldn't have guessed better mpg w/265/70's over 235/85's. What pressure do you run in 235/85's? Just curious as I have contemplated the 235/80/17 size for mine. (I'll probably settle on the 255/75/17.)

Thanks,
:cheers:

Well, I think the biggest factor is the overall diameter and weight. The 235's are all Load Range E, which means heavy. Add that to the bigger tire height and you've got a hit on MPG. The stock tires (265/70) are generally P-rated passenger tires. I believe I am at 45 or 50 PSI. It is rated to run at 80!

Some think the width affects the aero. It really does not, since the tire is inside of the truck. If it were an open-wheeled truck, then it would probably make a noticeable difference.

 

[Shoke]

I never said it increases the friction on the road. I said drag. As in a wider tire will catch more air than a skinny tire. Granted, it's not a HUGE difference in gas mileeage, it does make a difference.

Read the thread too quickly, Yes air drag is a totally different story