robertsunrus

Hi, my truck came with 18" LT tires. Door sticker says to inflate them all to 40 lbs. cold. Max cold pressure is 50 lbs. I never got any sway, but felt a slight push on turns. I set my rear tires to the max of 50 lbs. when towing and I leave my front tires at 40 lbs.

Deerchaser

Those aren't LT tires, they are XL. Most LT tires have a max of 80psi.
Mine came with 18" XL (extra load), I replaced them with Terra Grappler II E rated.

robertsunrus

Hi, come over to my house and look at my tires and tell me to my face that I don't have LT tires on my truck. They are load range "C" and have a max inflation of 50 lbs.

massspike

They are LT tires but the 113 load index (2535lb) puts them below my P rated 116 (2756lbs).

They may have a C load range (8 ply) but typically your LT tires (for towing) are E's (10 ply). I am not sure how much this matters if you don't have the load bearing.

77Ranger460

You gotta derate P tires by 9% when putting them on a pickup or pickup based SUV.

Siskiyou

The E rated or 10 ply rated tires have historically been used on 3/4 ton and up trucks, if you look at the load carrying capacity you will find that they can carry far more weight than a 1/2 ton could possibly carry. I have used them on a 1/2 ton truck and found them far too stiff. The C rated or 6 ply LT tires have stiffer sidewalls, beads etc than the p rated tires and I find a huge difference especially while towing on windy roads, couldn't tell any difference when I wore out my 10 ply's and went to 6 ply. The 8 ply you are referring to are actually D rated. I did a lot of research on the tires before I got rid of my stock standard load tires and the best way I found to explain the difference is the stock tires rating is a max load, not to be run long distance, where the LT tires can run that weight continuously. Also on trucks like Ranger pointed out they have to be derated because of the higher center of gravity and too much stress on the sidewalls.

robertsunrus

Hi, well at 2535 lbs. each, if my math is correct, that would give me 10,140 lbs. for a truck rated at 7650 GVWR. I think that should be good enough.

vanion2

I am running E rated tires on my F150. Maybe it's my suspension but they seem to ride just fine. Opinions vary so YMMV.

Still, as others have suggested I would recommend filling your tires to max PSI when cold. Also recommend leveling the hitch on the trailer and making sure the trailer tires are at max PSI when cold. Check their age as well and their tread for uneven tire wear. That alone can create sway. What are the speed ratings on your trailer tires?

If that doesn't resolve the issue I would invest in a sway kit or look at how you load the trailer. 60/40 weight distribution front/back of the axle(s). Also, transporting fluids are prone to promote sway so try to completely fill any containers.

If all else fails then just go slower. Not the answer you probably want to hear but it will get you home in one piece which is better than the alternative.

jcb206

You don't need LT tires. Inflate the ones you have.

The weight not being distributed correctly on 5500 lb trailer is your best bet. Remember, over 5000 lbs, you need a WDH. Probably need a sway bar too.

gmb13

Rather than look at a problem with the truck, start at the trailer. How is it loaded? 60/40 weight split? Too little tongue weight will throw any truck all over the road. Try moving some weight forward and see if it helps.