OK, I've finally broken down and am buying new tires for the Ford F150. I have a 24ft travel trailer that weighs in at 4800#, loaded and ready to go. The truck is about 4600# plus the weight of the occupants. I know I want to go to a light truck tire, but what specifications? I keep hearing things like "ply", etc. What do I need to look for in a good light truck tire without telling the man to give me the best he's got and open my wallet!!
Thanks for any help.

Jim

 

I'll bet the tires you have now probably aren't even an LT rated tire. (if they are the stock ones)

You should be fine with a Load Range C tire at any rate. The actual weight of the trailer is not really a factor for the load on the trucks tires (it matters for the load rating on the trailer tires, however). Just the added tongue weight of the trailer is what gets "transfered" to the truck, and that should be at the most, 1000 pounds.

I think the "C" tire is rated for 2450 lbs each at 50 psi, or 4900 lbs for the rear axle. You've probably only got 2000 lbs on the rear axle when empty anyway, and even loaded up, you shouldn't be putting in more then 1000 lbs in the bed anyway (really depends on what payload package your rig has).

That would be one maxed out load for an F150 anyway, but, technically, still within the tires spec.

You could go up to a Load Range "D" tire if you actually load up your rig to the max. It's max psi is 60 lbs and I think it's weight rating is around 2600 lbs each. It may ride a bit harsher when empty with a higher load range tire, but you'll just have to decide what you need most.

 

Other than your choice of all-terrain,snow/mud etc...what you want to look for in a light-truck tire is the load rating. With your travel trailer, make sure you get a D or E rating on your tires. It will be clearly marked on the sidewall.
When you trailer, make sure to inflate the tires according to the load you are putting on the truck, this will also be printed on the tire. My tires are E-rated, and can be inflated to 75psi for extreme payloads (up to an including 3000lbs on each axle). I drop that to 45-50psi for everyday driving.

 

I was told by my local RV dealer that a truck tire is also under extreme loads under braking and turning with a trailer, and therefore you should get more load rating than just the tongue weight of the trailer. The load rating is a measure of the tire's sidewall strength and resistance to delamination under horizontal forces.

 

When one does go for an 8 ply load range D tire like I was thinking about (I too will be towing a travel trailer of about 5Klbs), how do you know the pressure to put in when not under load? I doubt you can inflate to the psi listed on the door jamb. I also wouldn't ride around on 75 psi (my hemmorhoids would be unhappy). And, an underinflated tire can cause heat problems ala Firestone. Do the LT series have minimum and maximum pressures listed on the tires?

 

...on the sidewall, starting with 50psi at x weight value, 60, 75 etc. The minimum was listed as 45psi, the maximum 75psi.

 

jmorrisonbc: Good point on the turning and braking parts.

What I find interesting is that the stock tires, even with the towing package are only "P" rated tires! This is on the F150, at least the way mine is setup.......

I know the F250 LD and the F150 7700 package have the LT type tires stock, but in my case, and that is what I assumed for "penguin149", is that you get a passenger tire from the factory.

My rig has a GVWR of 6,250 lbs and a GCWR of 12,700 lbs (according to the owners manual) and it has the factory towing package. This is for a F150,4x4, auto, super cab, 5.4 w/3.55 gears. Your spec's may vary........

Doing the math, I should only be able to get 6,450 lbs for the trailer, assuming a full 6250 lbs truck weight. Even thou the manual says that the max trailer weight can be 7,700 lbs!!

All this with passenger rated tires!! I think NOT!! I've got LT265/75/16 load range C tires on it now. I think I'm even supposed to subtract 500 lbs because of the taller tires! (the same as a 265/70/17). And I think the 17" ones are passenger rated from the factory too.

Anyway, it is best to err on the side of caution, and getting a tire that is rated for way more then you really need is the way to go.

I only got the C rated tires, because it meets my towing/hauling needs. I plan on getting a travel trailer in the future, but only going to get one that has a max weight of around 5500 lbs. If I need a bigger trailer, I'll get a bigger truck........

PS. I keep my tires inflated at 42 lbs on all four for everyday driving. I'll pump the rears up to 50 when I haul a full load or tow. I came to the 42 psi on trial and error. Seemed to just ride the best at that pressure.

 

Ya'll are right!! I have passenger tires (with 36,500 no less!!) right now. I swore I wouldn't go through another towing season with these tires!!! They are Firestones P235/70/R16 and I want to go to the LT 245/75/R16 - this should match up pretty well with my gear change from 3:08 to 3:73 last year. My speedo is still about 5%-6% off after I changed the gear in it too.

Jim