Load Rating for tires???

Ok I am ready to order tires, What is the feedback on load rating? I know the 715's are a little on the heavy side but how important is the load rating? I am planning to use this as my tow rig, will see very little offroad use.
I am installing CUCV axles and a 500 caddy so the weight should be close to stock maybe a few pounds more. I am buying 40's looking at the Toyo's or Goodyear MTR's load rating is 120 on the goodyears and 130 on the Toyo's.
Anyone run less rating? Any issues?
Any feedback would be great, do not want to spend the money and find out I did the wrong thing.
Thanks Andrew

The Michelin XZL tires on my M715 are US load range E which is 135 in your system. Or at least that is what it says on the side of my tire.

I would suggest a load range of D at the very least. That to me means go with the 130 rated tires.

To expand on what Barrman said the load rating letter indicates how many plies a tire has.

Usually more plies means a stiffer tire which is safer for heavy loads and towing.

I was pushed for time when I replied earlier. Let me write this about towing with the M715.

I probably have 5-7 thousand miles pulling trailers or other vehicles with my M715. The trailers ranged from 500 pound single axle things to 2000 pound trailers with another M715 loaded up, a M37, full size Bronco, lots of baby Jeeps, M1009, Suburbans and multiple regular cars and trucks. Flat towing M1009's, M35's and a few other projects.

I have stock brakes on my truck with a dual master cylinder. They work ok, but trailer brakes are a must with any trailer. The M715 is heavy all by itself. I know you are putting 4 wheel disc brakes on yours, but you need to wire up a trailer brake controller.

For as big as it looks, a M715 is really a small truck. Mine is sitting in my class next to a 1988 K3500 single cab long bed truck. The M715 is shorter. It is also thinner. Not really the best then to have when pulling a trailer. Just getting the mirrors to see around the trailer is a pain sometimes.

I have a locker in my rear axle. A CUCV rear axle will also have a locker. Pulling a trailer in the rain is torture. I mean it will scare the day lights out of you. When the M715 was my only pulling truck, I went as far as making axle blanks so I could pull the rear axle shafts out, install the blanks and drive in the rain on front wheel drive only. I also collected a NP205 so I could twin stick it to make the front wheel drive only option a lot easier.

My XZL tires have a max pressure of 80 psi. Towing with all 4 tires at 80 is very stable unless it is raining or the road is twisty with lots of fast yellow lights. The short wheel base is a killer braking on a curve going down hill. It is also a very, very stiff and rough ride.

Lowering the psi to 25 front and 45 rear makes the truck almost comfortable empty. It also makes it feel like a marshmallow with a trailer.

My conclusion was that even though it will pull trailers ok. I was better off using my M35 or 3/4 ton diesel Suburban. Do as you wish, but please be aware of some issues I had.

Thanks for the feedback, I am going with the Toyo's at 130 load rating. The only thing that will be towed is my A1 on a small car trailer, so I am hoping that is does not cause to much grief. If it does the locker will be replaced. I only plan on using it 1 or 2 times a year for going to the Jamboree's so hopefully it will be fine.
Thanks again
Andrew