Larger Tires, E load range and tire pressure

[Agitated]

You guys that have went to a larger tire probably had to use an E load range tire. At least I did when I went to 275/65-20. There were little to no tires that size a C or D load range. Anyway, the E load range tire calls for 80psi at its max load rating. I'm trying different pressures to see what works the best between ride, wear, and proper pressure to carry the load (mainly on the rear axle). I'm coming up with 38-40psi. Anyone else have a preferred pressure?

 

[Edwards]

Part of it is preference, part is dictated by load required (much wider range on heavier HD trucks) and part on tire wear.
My wife drives a diesel Excursion that eats tires. It's over 8,000 lbs empty. I ran the last set at 55psi and the outer tread wore more quickly indicating I need more pressure just to keep the tread flat on the pavement.
75-80 psi is a harsh mistress in that rig.

 

[FLG8R]

You guys that have went to a larger tire probably had to use an E load range tire. At least I did when I went to 275/65-20. There were little to no tires that size a C or D load range. Anyway, the E load range tire calls for 80psi at its max load rating. I'm trying different pressures to see what works the best between ride, wear, and proper pressure to carry the load (mainly on the rear axle). I'm coming up with 38-40psi. Anyone else have a preferred pressure?

I don't know if this will help any but after that Ford Explorer debacle years ago where Firestone / Ford exchanged blame for all the accidents it seems one thing that was a contributing factor was UNDER inflated tires that developed too much heat. Myself I've always been in the habit of OVER inflating my tires by 4 lbs above the door decal recommendation. But never at Max allowable for fear of getting beaten to death by my own trucks ride. I do see that you're talking about after market tires but wouldn't the door decal still be used for inflation numbers?

 

[Agitated]

Well, actually 38-40 psi is overinflated from what the OE tires and door sticker calls for. But it's a whole different kind of tire and I'm not sure if 35psi in a D load range equates to the same load capability as 35psi in an E load range or not. Obviously that load range is overkill for a 1/2 ton truck and I'll never need max of 80psi, not would I want to.

 

[FLG8R]

Well, actually 38-40 psi is overinflated from what the OE tires and door sticker calls for. But it's a whole different kind of tire and I'm not sure if 35psi in a D load range equates to the same load capability as 35psi in an E load range or not. Obviously that load range is overkill for a 1/2 ton truck and I'll never need max of 80psi, not would I want to.

https://www.tirerack.com/tires/tiretech/techpage.jsp?techid=55
Try this read to help clear up things.

 

[SpeedyV]

You guys that have went to a larger tire probably had to use an E load range tire. At least I did when I went to 275/65-20. There were little to no tires that size a C or D load range. Anyway, the E load range tire calls for 80psi at its max load rating. I'm trying different pressures to see what works the best between ride, wear, and proper pressure to carry the load (mainly on the rear axle). I'm coming up with 38-40psi. Anyone else have a preferred pressure?

It's a balance. When running oversized tires on stock rims, like I do now, there's a risk of 'crowning' if the tires are wider than stock. This can lead to premature wear along the centerline of the tread, and it is exaggerated if you run max pressure without a load. Meanwhile, if you run those same tires underinflated, you put additional stress on the sidewall of the tire, which compromises tire life and stability. My factory-recommended tire pressures are 80 psi front / 55 psi rear (3/4-ton truck) when unloaded, and 80/80 when towing. I find that to be harsh. I'm also running (slightly) oversized tires and rarely tow, so I typically run 55/55. It's enough pressure to keep the tires wearing and performing correctly, but not so much that it beats me up.

 

[Agitated]

My tires are the same width, just taller. Those pressures are odd for a 3/4 ton truck. My F250 was 65 front/65 rear unloaded, and 65/80 loaded.

 

[96Dodge4x4]

My tires are the same width, just taller. Those pressures are odd for a 3/4 ton truck. My F250 was 65 front/65 rear unloaded, and 65/80 loaded.

I know for newer 2500 rams its 60 front 80 rear. Never heard of running 80 in the front

 

[SpeedyV]

I know for newer 2500 rams its 60 front 80 rear. Never heard of running 80 in the front

Yeah, I had that backwards...55 front / 80 rear unloaded. 80/80 loaded. From the factory, this old rig also has electronic shocks in the front that stiffen when towing to prevent front end hop.

 

[96Dodge4x4]

Yeah, I had that backwards...55 front / 80 rear unloaded. 80/80 loaded. From the factory, this old rig also has electronic shocks in the front that stiffen when towing to prevent front end hop.

That's pretty cool never knew about those before

 

[mjharden]

You guys that have went to a larger tire probably had to use an E load range tire. At least I did when I went to 275/65-20. There were little to no tires that size a C or D load range. Anyway, the E load range tire calls for 80psi at its max load rating. I'm trying different pressures to see what works the best between ride, wear, and proper pressure to carry the load (mainly on the rear axle). I'm coming up with 38-40psi. Anyone else have a preferred pressure?

Not sure if you got your question answered or not, but perhaps this will help. When I had larger tires on another truck, I called up the tire manufacturer (Toyo customer service). I told them what type of truck I had, etc. and they spit out a proper inflation number.