Originally Posted By: Digital2k2
Surprised I didn't get more responses about tread wear.
Put a P265/75R16 on a 7" wide wheel and get excessive center tread wear even down at 30psi with an empty bed. Will an LT265/75R16 At it's required higher pressure, say 45psi, wear more evenly due to it's stiffer innards? Or is most of the extra reinforcement on the sidewall and not below the tread?
Sorry I didn't respond to your original question, but here goes.
While inflation does have an effect on evenness of treadwear, the affect is small. What is likely driving the center wear is that the tires are on the drive axle. Drive axle tires tend to wear in the center, while steer axle tires tend to wear in the shoulders. Regular rotation evens things out.
Adding inflation pressure tends to slow the wear rate (tire wears more slowly) at the expensive of traction, because the tire is now overall stiffer.
So you would think that LT tires would wear more slowly because they are inflated higher - and that's only partially correct. They also wear more slowly because of the tread ribber compound. On the other hand, they have less traction and consume more fuel.
And here's where it gets difficult: When you compare P type tires with LT type tires, it's hard to get apples to apples comparisons. There are HUGE difference within a given type (P or LT). To get a good comparison, you have to be very careful - and usually, people are making the switch to deal with a particular issue they are having, so they never see a "like to like" comparison.
And one last thing.
Inflation pressure has much more of an affect on treadwear than the construction does. If you've ever rolled a flat tire around, you'll know it is quite soft and floppy (That's a technical term, folks!!) But add some pressure, and it gets quite stiff. Even with just a little pressure, the stiffness goes up a lot - to the point where at normal usage pressure, the construction hardly has any affect.
The other part is that the differences between the construction of LT tires and P type tires isn't as much as you might think. While it takes twice the strength to contain 60 psi than it does 30 psi, getting twice the amount of cord is easy. Polyester fabric comes in a variety of sizes, and to get twice the strength only takes a 40% larger cord (Area of circle sort of thing). That doesn't change the stiffness as rapidly as the increase in strength.