Tire Pressures on Tow Veh

[libtech01]

Hi there,

I have a 2005 Dodge Ram 1500 SLT. I had Bridgestone Dueler REVO AT 2 tires on it last year which were a P265/70/R17 tire. They are apparantly rated at 2535 lbs @ 44 PSI. Last winter I put on light truck tires, with a C rating and more plys instead of a passenger tire. I put on LT265/70/R17 BF Goodrich AT KO2's.

Ultimately I am wondering what tire pressure to run them at now. I contacted BFG and they said they wouldn't comment as these tires are not made for my truck.... Looking online, it seems like the lighter passenger tire is rated for a heavier load at a lower PSI as well?

Bridgestone Dueler P265/70/R17 - 2535 lbs @ 35 PSI. (MAX PSI is 44)
BF Goodrich AT KO2 LT265/70/R17 - 2470 lbs @ 50 PSI.

Door sticker pressure is 35 PSI. I am running about 42 PSI right now as I felt the 35 was a bit low. My worry is that If I run to low, it wont be high enough for when I have by trailer on? And If I run to high, the center of the tires are going to wear bad.

Thoughts?

[Ohio_Engineer]

ktosv wrote:
Bridgestone - Firestone Inflation

Here is a link for Bridgestone/Firestone. Looks like your 2255# is correct.

If you only use the truck to tow 10-20% of the time I think it is wise to adjust your pressure as needed. I know people who ran the center of their tires bald from running 80psi on the rear of empty 3/4 ton trucks.

I always adjusted on my one ton van cause it rode so much better empty with less pressure, but rode so much better loaded at max pressure.

80 psi is the top inflation for LR-E tires.

It really isn't that difficult to learn what the correct inflation is.
1. Get the TV on a scale when empty (as you might normally drive with no TT or load in the bed.
2. Get the TV on a scale when fully loaded (as you would be when towing and leaving for a trip.

With the above numbers you can then consult the Load Infl tables and learn the MINIMUM inflation needed for the two different conditions. probably both the F and R need to be raised when towing or lowered when empty.
If you don't lower when not towing you will be wearing the center of the tread faster.
If you don't run the min infl when towing you are damaging the structure of the tires and might see a failure before they wear out.

NOTE your COLD set pressure should be Minimum + 10% to allow for day to day temperature variation as that will affect tire pressure (2% for change in 10F) and while it is OK to run a little high it is definitely NOT OK to run under the minimum needed to support the load.
I trust you understand what the "cold" inflation pressure is.

[libtech01]

Not sure what the good grief is for..... Thanks for the help everyone.

[coolbreeze01]

Good Grief :S

[SoCalDesertRid1]

Run the rears at the full 50 psi pressure any time the truck is loaded/towing.

[ktosv]

Bridgestone - Firestone Inflation

Here is a link for Bridgestone/Firestone. Looks like your 2255# is correct.

If you only use the truck to tow 10-20% of the time I think it is wise to adjust your pressure as needed. I know people who ran the center of their tires bald from running 80psi on the rear of empty 3/4 ton trucks.

I always adjusted on my one ton van cause it rode so much better empty with less pressure, but rode so much better loaded at max pressure.

[mkirsch]

It's true that a Load Range C tire doesn't gain you much load capacity over a P rated tire, but that is not why you got them.

The reason you got them was for the stiffer sidewalls, which will provide you better handling and control.

[libtech01]

I did some digging. What I found was that P metric tires, when placed on a SUV or truck need to be de-rated to 91% of load. So that means my original P metrics are really about 2306 lbs at 35 PSI instead of 2535 if I am understanding that correctly.

Now I found this load chart, and based on my tire size and C range, 45 PSI should put me at about 2255 lbs, which is pretty close. This is a TOYO load inflation table, but I believe all LT tires have the same ratings from what I read. So if I run about 45 PSI, it should be rated about the same... I hope.

So for now, I'll try run 45-47 PSI when towing and see what happens. Thats still under the 50 PSI max.

[ktosv]

Can you do a google search for a load inflation chart? Seems to me like I had found one for Bridgstone when I had a tow vehicle with Bridgestone tires. Or maybe I had found a Firestone one and called it close enough...

[the_bear_II]

I have always had light truck tires on my tow vehicle.

I use the sidewall as the guide and fill to the maximum. I don't have the time to lower the pressure when empty and fill it up when loaded so I just keep them at maximum pressure.

I do the same with the tires on the trailer and cars.

I don't see excessive wear on any of the tires.