Tires: P Metric vs LT, nissan titan, load ranges

Question
I have an '05 Nissan Titan. (P285/70 R17). OEM tires where BFG Rugged Trail TA's and lasted 32k miles. Replaced with Bridgestone Duelers and they lasted 36k miles. Would switching to a LT vs P tire help my tire life?. I do tow a boat in summer. I like the greater tread depth on the LT285 Dueler vs the P285 and thought this might help the tires last longer than 35-36k miles.

Answer
Eric,

I am not a fan of replacing P metrics with LT metrics.  While I have heard lots of folks extol the virtues and their success stories - which I don't discount - I approach this subject from purely an academic position.

LT tires take more pressure - about 15 psi - to carry the same load as a P metric.  Why?  The only thing I can figure out is that LT metrics have high unit loading - a large amount of load carrying capacity compared to the amount of space they occupy - for the higher load ranges (and therefore, higher pressures).  The rubber used in LT tires is correspondingly strong - and what comes along with that is a susceptibility to cracking when flexed.  

So unlike P metric tires, which are designed to flex, LT metrics are not designed to do so.  While this is mostly thought about in the sidewall, because of the difference in the way these things are designed and tested, this carries over into tread and belt durability as well - meaning tires falling apart.

I don't have any good reliable data to back this up - as this type of trade is rare enough to be thoroughly obscured by return data.

But I don't think the problem with tire wear will be solved by going to LT metric tires.