tire life expectancy......

[tim s]

which tire will wear out faster or will they wear the same if i had to choose between the stock size 225/60/15 w-rated & a 235/45/17 w-rated. obviously the 17" will grip better but will it wear out quicker???
thanks
tim s.

[Tiger]

Treadwear rating will tell you which will wear out faster... tire size don't matter.

[NoSpeedLimits]

Tiger is correct, to expand: This is shown as a three digit number. A rating of 100 means a tire should last 30,000 miles under specific test conditions. A rating of 200 would last 60,000 miles, ect. These are not guarantees, nor even approximations of the mileage you can expect in your driving. They are merely for relative comparison.

[Bill R.]

Here

Tiger is correct, to expand: This is shown as a three digit number. A rating of 100 means a tire should last 30,000 miles under specific test conditions. A rating of 200 would last 60,000 miles, ect. These are not guarantees, nor even approximations of the mileage you can expect in your driving. They are merely for relative comparison.

[Tiger]

Wrong... every 100 is 15,000 miles max.

[Hector]

The wheel DIA doesn't make a difference but the width of the tire does. If you're driving habits are kept the same across the board, for both tires rated w (speed of 270,) the wider tire will last a bit longer because there is more contact patch which translates to more cm2 of rubber contacting the ground. This means that you have less force/cm2 of pressure exerted by the road at any point of contact so you should see less wear. However, you would compromise a bit of fuel economy.

[Mr Project]

Something I've always wondered, though....is the reduced fuel economy due in greater part to the increased surface area on the ground, or the increased aerodynamic drag of the wider tire?

[Hector]

experts might argue otherwise. Some say that rolling friction is independent of tire width whereas others argue that it's not. I believe it is.

It's both, and they are speed-dependent. Studies have shown that the rolling force is a factor at low speeds whereas air drag becomes dominant at high speeds. The increased tire width will play a small role in air drag but this becomes a wash at high speeds where drag from the car body dominates.

Something I've always wondered, though....is the reduced fuel economy due in greater part to the increased surface area on the ground, or the increased aerodynamic drag of the wider tire?

[NoSpeedLimits]

As Bill R. said..."Not quite"...you can not change the size of the contact patch unless you a) alter the amount of air pressure or b) change the weight of the vehicle. Sorry, but I do not have a link to support my claims, but believe me it is true. A wider tire will only alter the shape of the contact patch.

[Mr Project]

Yeah, you'd be doing pretty good to get 35-40k out of a 300 treadwear tire, in my experience.