Tire Load Rating and load index

[rick619]

I'm looking at tires and not sure what load range I should be looking for. I want to get an AT tire mostly for looks. Though I do want to be able to tow with it. I'm not towing much, don't have a trailer yet. So not sure if I'll be flat towing or getting a trailer.

When I lookup one of the tires I'm considering, Cooper Discoverer AT3, it shows the load range as SL. Load index shows 115.

SL - Shows 36psi max. My tires are currently at 40 psi. So not sure if I need to look for something that can handle higher psi? I've seen people mention going up to 60 psi for towing which would be at least a D1. D2 shows 50 psi.

Load index of 115 - When I lookup load index of 115, it shows weight of 2,679. When I look up weight range for a Big Horn, I'm showing 4853 - 5373lbs.

So what am I missing here?

 

[Gren71]

In the Jeep world it was all about side wall strength… So a lot of people went with D or E rated tires for the added sidewall rigidity. I think the load rating depends a lot on how you intend to use your truck.

For example:

The primary purpose of my truck is a highway rider and a trailer tow vehicle. So I went with an XL load range tire. The XL load range can handle higher psi (50 cold) but is similar in overall tire weight to the OEM tires. So minimal effect on daily drive feel and fuel efficiency.

There are others who tow heavier than me, and they require E rated tires for the added sidewall strength to help with the side to side motion on the highway caused by side wall flex.

There are also fellas who do a lot of offloading and the added sidewall Strength helps a lot with preventing rock and debris punctures, and gives the tire a good grip on rocks as the sidewall flexes around it at lower psi’s really well.

The SL tire range is perfectly fine for most daily driving and normal use purposes. On my old gladiator I used to run SL rated tires even while towing and had absolutely no issue. I ran Firestone destination AT2 tires. They are considered a more high styled AT. They looked really good on the jeep with the outside wall white lettering and aggressive, tread pattern. But I was still able to get 20 miles per gallon on the highway unloaded

If I’ve gained anything over the ridiculous volume of tire threads across a bunch of different forums, it’s that at the end of the day nearly any tire will get you 95% of the way there… And most people get wrapped around the axle about the remaining 5% of information. Stuff like load Rating E versus D versus SL, or AT verse HT verse Highway all-terrain verse all season verse etc. there’s no one-size-fits-all so you just have to do your best.

For what it’s worth I ended up going with the Michelin defender LTX MS2 with the XL rating. Gives me the best all season highway and mild off-road (beach driving) tire out there with a crazy high mileage warranty. I inflate my rear tires to 40 to 42 and leave my Front at 38 while towing. At that PSI, along with other suspension modifications I’ve made, the truck is rock steady, even when big rigs passed me on the highway with my camper hooked up.They definitely don’t look very truck like… But after living in the world of jeeps, I’ve landed at function over form.

 

[rick619]

Yes, I'm in that boat too. I want the look of an AT, but know the Michelin Defender is what I should probably be running. I do have Nitto Ridge Grapplers on my Jeep. Still like the AT look for the Ram.

Started looking because someone on Facebook mentioned the Walmart specific Cooper AT that are on Black Friday special for $140. Those seem to be listed for lighter SUV's though.

 

[Bt10]

Just to round out the info: the rear axle is rated for 4100lbs, divided into two tires is minimum 2050 lbs carrying capacity. You had listed truck empty weights, which aren’t relevant. The max PSI on the tire is not what the truck should use. Follow the sticker on the B pillar - it is sufficient for the rated weight of a fully loaded truck. If you change tire ratings, there are tire websites that have charts to determine the correct PSI.

Most (all?) tires in the size ranges of the truck are acceptable, but there are trade offs with each choice. In addition to sway and toughness mentioned already, mpg and acceleration also takes a hit with higher tire weight.

Sidewall height also plays a role in towing sway, with 18” light duty P rated the worst, to 22” E range the stiffest.

 

[mplaramie]

Great info but I'm not so smart and still confused. Here's my dilemma....
1. Have 22" 285/50/22 load E Toyo AT3'S. Love the tire but super stiff and heavy.
2. Going 20" wheels in spring and looking at P285/60/20 Toyo AT3'S vs LT285/60/20's (load E).

Is the P285/60/20 my best bet for a lighter tire? No issue being P rated vs Load E?

I don't tow anything more than an atv or snowmobile if at all. Bed weight is empty unless I'm suckered into helping someone move, yearly landscaping crap, etc.

 

[Bt10]

You would want and be perfectly fine with the “P” tires, but I have seen shops that won’t mount them on trucks with a door sticker calling for C or higher, even with a load rating well above axle rating. About half you can convince to actually look at the numbers to understand, the rest are illiterate gorillas. Good luck!