I always just used the term passenger, which you refer to as SL. Honestly I am pretty ignorant on the ply build of the tires. You never see that listed in any of the specs so I don't reference it as I do not have anything to point to.I thought it's usually the P-Metric SL with 4 ply equivalent walls, and C load with 6 ply equivalents? Usually the C load are considered a 6 ply equivalent but still carry less load (lower index), yet have the thicker LT tread and tougher/thicker sidewall. They are usually rated to higher pressures although that isn't really needed on a Frontier. Overall the C's, while rare in metric tire sizes, are usually considered a good option when available because they still support enough load, have thicker sidewalls, deep tread, but ride like an SL and wear like an E, only at the cost of a lower 109ish load index rating. IT's sort of like the C load tire combines the good from both E's and SLs and leaves out the bad from both. That is my understanding anyways.
I'm planning on getting the C rated 265/70R17 ATX next time. Didn't know it existed when I bought my SLs of the same tire or else I would have gone the same route.
THe ATX is a perfect example. It comes in all 3, C, SL/Passenger, and E. Tirerack also has a pretty good spec sheet so I did a little summary. If possible I buy an SL tire, they are cheaper and carry more than the C. Been told that generally a SL is an entirely different tire than the LTs. Even the size is different enough.
|General Grabber A/TX 265/70/r17|
|Type||Load (lbs)||Max PSI||Cost ($)||weight (lbs)||thread depth (in)||width (in)||height (in)||$/32"|