has anyone toed any heavy loads with p rated tires? my boat is pushing over 6500 lbs plus i'll have a loaded bed. maybe another 300 lbs of vacation stuff.

 

Yup. Lots of times and once over twice as heavy as your boat.

https://www.ford-trucks.com/forums/1...o-the-max.html

https://www.ford-trucks.com/forums/1...new-truck.html

https://www.ford-trucks.com/forums/1...new-truck.html

https://www.ford-trucks.com/forums/1...heavy-tow.html

Coming from a couple of Super Duties before this I was always impressed with how stable this thing was with the factory P-metric tires. I didn't feel any need to upgrade pulling my enclosed car hauler, and so I don't see any reason to upgrade for your setup.

 

I was about to look at Tire Rack for tires, so I checked the load ratings
for 275 65 18s. The P rated tires have a max load rating of 2600-2800 lbs
at max inflation.
There aren't many C load range tire choice. The only one I saw had
a lower rating the the P tires.

There more choices in E load range.
That gives you a max load rating of around 3400 lbs.

By the numbers, you'd be well within the weight limit with the P tires.
Calling these "passenger car" tires is as much a misnomer as calling
your truck a "half ton."

http://www.tirerack.com/tires/tirete....jsp?techid=70

 

Sooo 2600 x 4 is 10,400 pounds. What is your GVWR? You are distributing the weight over 4 tires and your tongue weight can be 1000 pounds MAX, and that is with weight distribution equipment. I'll have to research more but I'm almost sure I read somewhere that the weight ratings of modern P metric tires exceed the axle weight rating.

My advice as always though is whatever makes you feel most comfortable.

 

I just looked at the placard on the drivers door of my truck. It's
a 4x4 KR Screw, without any heavy duty packages.

Basically the truck weights about 5800 lb and the max legal gross weight of the
truck is 7200 lbs.

So, using your numbers, I'd have 200 lbs in gas, 300 lbs wife and I,
1000 lbs on the trailer ball (15% of your 6500 boat) and 300 lbs for your
supplies.

I'm now 400 lbs. over max gross but well within the tire limits.

Your numbers may be different if you have a heavy duty package, but
I'd say the truck will be the more limiting factor, not the tires.

 

Thank you! I worked the numbers already but didn't post them because it was during a conversation with a friend and I didn't bother to save them, but the conclusion I came up with was the same.

I also read somewhere what the axle was rated for, but went hunting for it and couldn't find it, but IIRC, the rear tires together were rated for slightly more weight then the axle.

IAC, for me anyway, it made more sense to not pay the higher price for LT tires while sacrificing unloaded ride quality and just go with what Ford put on the truck to begin with that brought me the 38,xxx miles before I changed them…and still made $20 a piece on at 6/32 tread left.

 

I think the truck is designed to max out the GVWR before the axles or factory tires. Some people use LT tires for the added sidewall strength to help control sway.

 

Tom proved repeatedly that these trucks can ride nice and work hard on the factory P rated tires.

 

I bought P rated tires 265/70/18 55k rated Cooper AT3. They are shot with less than 40k mileage so I was thinking maybe pulling a bass boat a lot made the P rated tires wear faster. Not sure if that was it not.

 

I didn't disagree just repeated what I found out from others. I guess the standard RSC helps make the P rated tires work better. Since Tom repeatedly proved this, I guess it's a closed case then...end of discussion.

 

I hope you didn't take my comment as being short or rude, simply an observation and a feather in Tom's cap.

At the end of the day, I think a person needs to do what they feel comfortable with. If LT tires fits the bill then so be it, they are available for a reason.

The car builders mount P rated on trucks mainly so the first test drive makes you feel like your in a more comfortable, quiet and luxurious vehicle rather than a truck. It just so happens that P rated tires do work well on a half ton truck.

 

And yet they also mount LT. e.g. Current 2011 F-150 FX4 came with LT 285/70x17 as part of the 7200# GVWR Package.
.