E rated tire with max psi of 65?

MFL wrote:
...... While you SAY burst pressure the reason, then add that burst is many times the max pressure, it would seem that 80 psi rather than 65 psi, would not cause burst. .....

What's really going on here is fatigue strength. Wikipedia: Fatigue (material)

Tires are all about fatigue and in order to design a tire to go through 10's of millions of cycles (rotations), the designers uses the burst pressure as a reference and then uses a factor to increase the strength to get the desired fatigue life - which they get from an S-N Curve for the material in question.

So while tires don't burst at 80 or 100, or 150 psi, that burst pressure is an indicator as to the fatigue life.

MFL wrote:
Good to see where your info comes from. While there are many types of tires, if you would have taken the time to read the link Burb posted, it is a hybrid type (dual purpose) tire, that by design, would work best, considering sidewall and tread at 65 psi. Other tires purpose will vary, and while e-rated, may also be less than 80 psi. ......

Ah .... That's not how it works.

The simplest way to describe this is to say:

1) that the WORST condition is the onroad condition, because heat is the tire killer! So the fact that we are discussing an onroad/offroad tire still means the onroad condition is what the tire engineer has to design against.

2) that the tables were set up (over 80 years ago!) so that a construction for a given Load Range works for all tire sizes - which means that when a tire gets to a certain size, it can't withstand the stress, so the Load Range drops down to the next lower increment - in this case from 80 psi down to 65 psi.