To quote from the LT tires thread: "The horizontal lines on the P-metric tires (referencing the chart) represent the ability to add pressure for special conditions (like high speed) but the extra psi assigns no additional load capacity."

In other words, the load capacity of the SL tire at 51psi is the same as it is at 36psi.

I don't run Duratracs, but to chime in about load ratings...

I went offroading with a friend of mine who has a Forester with C load rated General Grabber AT2s. I was running E rated Grabber AT2s.

While treating our vehicles similarly over some rather jagged rocks, he popped a tire. I didn't. I run the LTs for puncture protection, rather than for towing or something like that. It's good peace of mine knowing that, I'm probably not ever going to puncture a tire offroad because I'm running tires rated for more abuse than my truck is capable of giving. And if by some chance I do puncture one, my spare is an E rated General Grabber, as well.

Thanks JB! Appreciate you taking time to explain it to me. I thought thee was a chance that it was just marketing, and the two tires were the same. Wrong.

This is old, but for the record, it is wrong. Many SL tires in 4R sizes have maximum pressure of 51 psi and the remaining ones are 44 and not 36. Load ratings between P and C are often identical after adjusting for LT application (which is a discussion in itself, since the 4R is not a pickup).

I have not seen one ounce of evidence that a C tire is necessarily stronger for offroading than a B tire. Of course, if the tire does have a 3-ply sidewall (like many LTCs in 255 75 17) then the C will be stronger.

It is the common perception that E-load tires have stronger sidewalls for offroading because they have stronger construction so as to hold 80 psi and thus higher loads.

But in practice, unless the E load has a 3-ply sidewall, the advantage is likely way smaller offroad than it is when hauling, which is the design parameter.

I could definitely use a tough tire offroad yet I am running SL which is better at everything other than sidewall strength. The trick is to run the SL at or near street pressures. By contrast, the E must be aired down both for traction (terrain compliance) and comfort. On road the only possible advantage of D or E is added cornering stability at proper pressures. The rest is a laundry list of shortcomings.

On Grabbers, at least, the sidewalls are rated at 10-ply. I believe it's a '3-ply rated at 10-ply' (not sure how that's actually measured) but like I said, it's capable of handling more abuse than I can throw at them with something the weight of the 4Runner. The hit in gas mileage was 1 mpg. Oh well. I didn't buy this thing for gas mileage.

I would much rather run an aired down (or even aired up, I've offroaded mine at 40psi and they're bumpy but still grip fine for light offroad) E-load and not worry about sidewall punctures than run an SL and not have to worry about airing down.

Also, that sidewall stability on-road is amazing. I've been in trucks with C-load Grabbers and they handle like complete garbage compared to mine with the E's. It's night and day. Otherwise though, I didn't buy them to be good on-road. I bought them to be good offroad. If your truck sees 90% pavement, yeah, there's 0 reason to get E-load tires. Otherwise, I see no reason not to.

Such a good question. I just purchased LT265/70R17 C load Duratracs and was puzzled by the same question. I also started to worry they were not rated enough for my 4R.


Fantastic info! The 112/109Q rating made no sense. So if i need the full weight capacity on my C's i can just add a little more (closer to 50) PSI and i am good to go. I'm running 35psi for now.

The C rated Duratracs ar 10 ply too.

Sorry to bump old thread but good info!

@JB.

Max PSI is 50 and max weight capacity is attained at that PSI. Wouldn't it be pushing the tire at 50 PSI?

Going to bring my PSI to 40 today.

I have a 5 Gen BTW.

Alright let’s beat this dead horse!

Anyone running or know if TRD pro wheels with 255/80/17 Cooper ST Maxx will cause any rubbing? Currently running 5100's all around with the fronts set at 0.85".