I am looking at a new set of BFG AT tires in the 285/70/17 size and noticed the D load range are discontinued and now they tag them with an E load range.
I also notice the weight capacity is rated the same but the "E" tire can take 80psi.

So whats the deal if they both only hold 3100 and change but the "E" needs 80psi to do it? I don't see the advantage?

Can someone explain this to me?

Thanks

 

The load range or ply rating branded on a tire's sidewall helps identify its strength and ability to contain air pressure. While specific load ranges are assigned to passenger tires, load ranges are identified in ascending alphabetical order for light truck tires (the further along the letter is in the alphabet, the stronger the tire and the greater amount of air pressure it can withstand and load it can carry). Before load ranges were adopted, ply ratings were used to identify the relative strength of light truck tires with higher numerical values assigned to tires featuring stronger, heavier duty constructions.

Today's load range/ply ratings do not count the actual number of body ply layers found inside the tire, but indicate an equivalent strength based on early bias ply tires. Most radial passenger tires have one or two body plies, and light truck tires, even those with heavy duty ratings (10-, 12- or 14-ply rated), actually have only two or three fabric body plies, or one steel ply.

 

Now when you think about pressures, the more pressure a tire holds, the less contact area it will have with the road. The less contact patch, the less flex. The less flex it has, the less heat generated. The less heat generated, the less likely it is to fail.

Heat is what blows out your tire. Fill those bad boys up when you are running loaded! Goodyear issued a TSB that their Marathon trailer tires should be filled 10 psi OVER maximum or you'll risk blowout.

I just had a light load on my new Dura Grapplers (6200 on the rear axle or 3100 pounds per tire) and pumped them up to 80 psi. I took a 200 mile trip in 20 degree temperature. Just to know, I stopped and checked air pressure when I reached my destination. I was at 92 psi. I would not have guessed the pressure would come up that much in the cold!

 

Me neither. Still generates some heat.
Regarding GY Marathons, I can't speak for the heavier trailer tires, but the C rated tires are still complete junk whether you run +10psi or not. I've been doing this for a while and it hasn't helped. Have had multiple tread separations on tires that were aired to max 50psi and 60psi (10 over). Should be a recall on them. It's bad enough that my local Big O actually warantied 5 tires for me that were 5 years old (past GY warranty) and refused to (thankfully) put Marathons back on the trailer. Just a warning for anyone running light duty Marathons. If you haven't had a tread separation, you're overdue! Sory for the threadhjack.

 

I have lost so many Marathons it isn't funny..... And on my fifth wheel, they take out expensive sheet metal and fiberglass! I went to a 'cheaper' brand of no-name tire and haven't had a problem.

 

Where are your problem Marathons made? My American made ones were great for over 10 years. I hear now that some are now made in China, and some still in North America, and I believe the Chinese ones have more quality problems. Does your experience back this up?

Most trailer tires seem to be made in China these days, and I really don't know what brand to buy to get a good one.

 

I don't know where mine were made. Mine are running loaded though!!! 2500 pound rating on a 13,000 pound trailer so I always had 3,000 on the truck. But still with tandem axles, you never have exactly 25% on each tire....

 

So the E rated BFG will not haul a heaver load than the old D but can be inflated to 80psi?

 

IIRC D rated tires are 6-8 ply rated tires 50 psi max and the E rated tires are rated at 10 ply 80 psi max. My self I will only buy E rated tires if it has a 3-4 ply sidewall as the 2 ply's sidewalls I've looked at feel weak compared to a 3-4 ply sidewall tire. Other reasons I only buy E rated tires is if your get into a wreck with D rated tires your insurance company can limit your coverage because your not using the required E rated or better tires for your truck as listed on the door plate. I've also seen many trucks hauled off the hwy with D tires because of a sidewall blowout even with light loads and also no loads.

One thing to remember is that not all E rated tire are equal, example the factory Michelin tires that come on my 2006 have 2 ply sidewalls and 3 ply's on the tread for 5 total ply's. The Coppers Discover STT I bought for my winter tires have 3 ply sidewall and 4 ply's on the tread for 7 total and they also weigh IIRC 4-5 pounds more then the factory tires and that 1 extra ply in the sidewall has less flex when driving then the factory tire.

 

Thanks for the info.

I guess I will hunt down a new set of BFG E load tires.

 

Also look at the speed rating. You will usually drop some top speed ability of the tire the higher you go. Also at a given speed the E will handle weight better. Stiffer side walls as well. Both the D and E are rated for 100 something i think but that is listed on the tire with a letter rating. it should be on the web sites or check out tire rack they explain it all.

 

Its not that they "need" the extra psi to hold the weight, its that you can put the extra psi in them. Which leads to improved tire life, handling, load carrying, and the tire const is heavier to accept the higher pressure.

Most LRE's are still 2 ply sidewall, some are 3. 2 is plenty if they are LRE. I have never seen a 4 ply sidewall tire in a LRE, and I have looked.

 

You will find you will have less "roll" with the E rated tire compared to a D rated tire. Around me Sam's and Discount tire would not mount a D rated tire on my truck (insurance reasons), they said they would only put an E rated tire on a 1 Ton.

 

To summarize:

There are a wide variety of E rated tires, but in general the E rated tire advantage for HD trucks is stability/control and less rolling resistance... needing less power to go up hills, better mpg, sidewalls that can take more abuse.

These advantages basically come from running higher air pressure so there is less sidewall flex. E rated tires need to be stronger, for the same weight rating, to hold 80 psi. Lower air pressure D tires have more air cushion (softer) to absorb pot hole shock, where 80 psi does not. E rated tires are typically targeted to the HD truck market so they may be able to take a bit more highway abuse.

On a heavy truck, E tires ride just fine, but on a passenger car you may find yourself bouncing off the road :-)

 

Lotas internet info on the bad tires.
There's problems with both American and Chinese made Marathons. Not sure what/when, but I've had these separate on me back as early as 03 and the tires were probably late '90s made. One recent set was US and the other Chinese, both separated, and like LostLake, mine damaged expensive gelcoated fiberglass fenders. The US ones lasted more miles (less load though) than the newer ones that were under a bit heavier trailer. None of them were loaded to anywhere near their capacity though.
SPeaking of Chinese tires, I have a set of D rated 14" Nankang tires on my sled trailer. 10yrs old, cracked from the sun, never covered or stored inside treads almost wore out and to date no problems. Only new D rated LT or ST 14" tires I can find are Kumho 857's. That's what I'll likely replace the sled trailer and boat when I need to.