The OP and anyone considering changing the class of tire should know
that it is re-engineering of that vehicles suspension system
The tire is only one component of the suspension system.
The tire's duties are:
- to hold up or carry weight, just like the
springs - accelerate by transmitting the axle torque to pavement
- brake
- steer
- more than steering, but holding it on a curve, a slalom, etc
Most folks only see and talk/address the 'carry weight' aspect as an
absolute (meaning that is all a tire does). Also the only thing between
the vehicle and pavement
With the abuse and misconceptions with tires, it is astounding to me
that they hold up. A testament to design margins dialed in by the
tire engineers...but...there is a limit or point where they will fail
Some instantly...others over a short time period
So much is taken out of context and as an absolute.
Confusion abounds with the different class of tires. From the above
and that they 'look' the same between classes (not all, but some)
Take a class 'P' and a class 'LT' from the same OEM, same model,
same tread design, same size, etc. One will weigh more and also
cost more. Why? Maybe the 'Z' rated 'P' class will cost more, but
that is a specialty tire vs a truck tire (LT)...or that most 'LT'
class tires are speed rated for 100MPH (most, not all) because pickups/SUVs
are not designed to run over 100MPH, generally
Then that confusion rolls over to their PSI vs weight carry rating.
That confusion is not just from those asking, but from so many advisers
PSI is NOT just for carry capacity (it is only ONE attribute) but
mainly for the tire to be able to keep it's shape between wheel rim
and pavement.
On that shape, note the the main or the greatest enemy of a tire is heat
Generally heat self generated by flexing with some ambient contribution. Oh, yes...the rim width also very important and tough
one to get folks to see/understand how that contributes to how
a tire flexes
Speed is the main 'flexing' issue for 'that' load
Then the specifications (published, door label, glove box manual,
tire sidewall, etc) taken as absolutes and out of context from one
class tire to the other class tire
Or the various ratings tossed in an absolute manner. Like a 'C' or 'E'
is thought to be it...but it is only a suffix or prefix modifier for
a tire size. A 'E' for one tire size has a different weight rating than
an 'E' for another tire size. There is a move to the 'P' class weight
rating with numeric identifiers and those are absolute. Meaning a 120
load rating for any size tire or class tire will have the same weight
rating.
There is a bunch more, but not now...no time as shopping and getting
ready for the 4th BBQ party...will come back to this later