Would you expect putting LT series tires on a '06 Nissan Xterra to do anything more negative than a somewhat harder ride and worse fuel economy? The vehicle came with P series, but I tow ~2000lbs with it a lot and want more solid handling.
Anyone out there with actual experiences going LT over P series? Thanks very much.
When you take into account that the P series tires have a weight carrying capability of about 10,000 pounds a set Vs. about 13500 pounds, for LT version and the fact that your Xtera weighs in about 4500 pounds, and the fact that the trailer has it’s own tires anyway. It really doesn’t much sense to go with the LT tires, as you are barely at 50% of their weight carrying capability. This an Xterra not an F-450.
Very true FoDaddy! 
I know I don’t need all the extra weight carrying capacity. I’m trying to determine if I’ll encounter any unacceptable handling or suspension consequences from the LT. Or conversely, if it’ll improve the handling, especially when towing. I’m trying to achieve the latter. Do you have any thoughts on that? Thanks for your time.
You will get better handling out of the P series tires. The real benefit of the LT tires is added load carrying capacity which in your case is a moot point. The LT tire may have more plys which could make for a more damage resistant tire though.
I’m sure the dealer can advise you depending upon your projected use as to the type of tires. As FoDaddy points out so well, there is little need for LT tires. W/O an open bed, it’s probably impossible to over load LT tires, even by mistake, on your vehicle. It rides tough enough as it is, don’t add to the pain :=(
Let’s start with some specifics:
A 2006 Nissan XTerra originally came with …oh a variety of tire sizes depending on the model, but let’s pick one that will be easy to deal with: P265/75R16 - and Nissan said to inflate those to 35 psi. That means the load carrying capacity of this tire is 2601 # (at 35 psi), but since it is used on a light truck, it has to be derated 10% to 2365#.
In order to carry the same load as a P265/75R16 does at 35 psi, an LT265/75R16 has to use 48 psi.
If you do this, obviously the ride is going to deteriorate greatly - and because the spring rate of the tires will be so different, your springs and shock will not be compatible.