skinnier tire vs LRR tire?

[tacopower]

I'm trying to decide which size snow tires to get. Current tires are 245/75/R16.

Current:
245/75/R16
30.5" diameter
32 lbs
7.6" tread width

Snow tire: Yoko Geolander I/T GO72:
245/75/R16
30.6" diameter (+0.1" from current)
34 lbs (+ 2 lbs from current)
8.2" tread width ( + 0.6" from current)
LRR

225/75/R16
29.3" diameter ( -4% from current)
30 lbs (-2 lbs from current)
7.6" tread width (= to current)

The 245s should be more efficient because they are taller and LRR, but the 225s should be more efficient because they are lighter and skinnier. Which factors are more important?

[CapriRacer]

As a general rule, size plays a small role in fuel economy. It's more about the tire than the size (as in the difference between specific makes and models of tires has larger differences than the difference in size alone.)

But directionally, a larger tire is better than a smaller tire.

I think that makes the choice obvious.

[tacopower]

Thanks for the response CapriRacer. So, You're saying that the gearing advantage of the larger diameter 245s will offset their greater weight and width?

[mcrews]

The two 245 tires are the same size. Not enough difference to even notice. You need to be at 5% difference to have any effect on mpg.

[roosterk0031]

For winter tires forget MPG, I think with a faily light weight Taco the narrower tire will give better on-road traction. I'm pretty sure you won't see a MPG difference that you can point to the tires, but higher ground pressure is better IMO. Apperantly tirerack seems to offer a one size narrower when looking for winters. I remember how well an old escort cut thru the snow with 155x13's.

[CapriRacer]

Originally Posted by tacopower

Thanks for the response CapriRacer. So, You're saying that the gearing advantage of the larger diameter 245s will offset their greater weight and width?

Weight is not the best way to determine the difference in rolling resistance. There are too many other variables that have a much greater effect.

And even if you consider weight as part of the inertia to get the vehicle moving, it is a tiny percentage of the whole vehicle - so largely undetectable.

[NickelB NL]

In my own experiance width is a factor for rolling resistance. A couple of years back i also had a ford ka. It got 16.5 km/l on 165's. And 14 on 195's. With the same trips

[2000mc]

Originally Posted by NickelB NL

In my own experiance width is a factor for rolling resistance. A couple of years back i also had a ford ka. It got 16.5 km/l on 165's. And 14 on 195's. With the same trips

that sounds like an awfully large change(15%), same diameter? If not, is it with the new ratio figured? Same tire model?

[NickelB NL]

Originally Posted by 2000mc

that sounds like an awfully large change(15%), same diameter? If not, is it with the new ratio figured? Same tire model?

The 15" 195 were a bit taller. And a different make/type. But i think the diffence is to big for just a different type.

[bikin' Ed]

Personal experience is that tire type can make a lot of difference. The tall skinny tires didn't help mpg at all.

Testing on bike tires has shown that a larger contact patch ( wider tire) yields a lower rolling resistance at the same pressure. I also experience a smoother ride with a wider tire/wheel combo -on both the truck and the bike. It also seems to take less powere on the bike using the wide combo on the bike.