What's the difference between a tire with a Load Range "D" that will allow for a MAX Load weight of 3195lbs@50psi and a Load Range "E" with a MAX Load weight of 3195lbs@65psi? I've read that D has 8ply & E has 10ply. How different is that, besides the obvious? Trying to decide on the BFG AT T/A K/O LT305/65R/17E and the LT315/70R/17D tires. This is an awesome sight.

Jerry

 

The 10 ply or Load Range E tires can take a heavier load. You can inflate a 10 ply tire to 80 PSI. It gives you a little more of a safety margin. About the last thing you want when you're towing is a tire failure.

A lot of guys that don't tow will use Load Range D tires. You'll get a little smoother ride out of those, everything else being equal.

 

Since they are both rated for a MAX Load of 3195 lbs, does that mean there is a difference in their towing capabilities?

 

The D tire will give you a little more squirm at the max load rating, due to the lower pressure and "softer" sidewalls.

 

My BF Goodrich Rugged Trail Load Range "E" 10 ply are rated at 3415lbs. I needed that to support my 3000lbs Truck Camper safely.

 

I don't mean to point out the obvious, but when calculating the load capacity of your tires don't forget to take into account the empty weight of the truck itself that the tires will be supporting.

Example: E rated tires can support 3415 lbs, times 2, that's 6830 lbs. Subtract the rear axle weight of your truck (not sure what that is, let's say it's 3000 lbs for simplicity). 6830-3000 = 3830 lbs you can add to the rear of your truck.

I think this makes sense, let me know if i'm all wet. Again not trying to be a smart butt, just wanted to point this out. .

 

You're right sandman3510, but not all "E" or "D" for that matter hold exactly the same. So, not all "E"s will be 3415. BFG makes a lot at 3195 and Toyo makes at least one that's like 3800 of something.

As Redford pointed out there will be more sidewall flex, "squirm", with the D tires, but they'll hold up the same weight if rated the same. You'll just feel it a little more when cornering, braking, etc.

I just went from an "E" to a "D" and notice the sidewall flex quite a bit. The "E"s were STIFF. The "D"s provide a much better ride; although both are rated at 3195. I bought the "D"s knowing that though and it was part of the reason I went that route.

 

The "ply" identification number has no meaning anymore. It was used to indicate the number of belts or layers of materials. The new letter designation is an equivalent indicating for example an "E" rated tire is equivalent to an older tire with 10 plys or layers. The development of new materials means my OEM BF Goodrich tires probably have only four belts.

Check this link for much more information about tires:
http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=55&currentpage=38

Very good point Sandman. In addition, do not forget a fudge factor in case of the loss of a tire by catastrophic failure. Have friend who had three tires go in succession (blow-out) on a heavy loaded trailer. Of course person never checked them before hauling. Duallies share the load in case of tire failure and engineers considered in the tire specifications.

 

Thanx for the many responses, as you can see, there seems to be many different interpretaions to what is meant by the load range index. I just wasn't getting it by reading the different tire sites.

 

I went to Sam's Club recently asking about tires for my truck, and they told me they would not mount "D" rated tires on anything that originally came with "E" tires.

Considering that I'm looking at 285/75R16's and a lot of those have a higher load rating at D than E-rated 235/85R16's do, I don't really understand why that's such a big deal.

 

Unless it's an oversized Load Range E tire....they are 65 psi.

My 325/60R18 Silent Armor Pro Grades are Load Range E, 3525lbs max @ 65 psi.

 

All things being equal, such as size and weight rating, an E-range tire will run cooler on the highway than a D-range, and it'll provide more sidewall stability.

The increased flexing of the sidewall in the D-range is the reason for the higher operating temperature.

For example, my brother-in-law once put D-range tires on an Isuzu box truck that had a GVWR of 11,500lbs. It wallowed (tail wagging) on the highway with a big load on it. Michelins.

Same style tire, E-range, made a HUGE difference in the stability of the truck. Even though the actual WEIGHT rating was almost the same.

They lasted a lot longer too ...

Which is why, for the most part, everyone here recommends E-range for the Superduty when it's used to the max of it's capabilities. It's just common sense.