I have a 2005 2500HD Crew Cab with the Duramax. I am wanting to find out what tire pressures I should be running when I am towing (6000-6500lbs) and not towing. The wieght is trailer loaded with car and supplies.
Thanks
Ray

I have firestone load range e and run 80 PSI in them when towing my 38' Toyhauler which weighs in the 15K range. When not towing I back down to 70 PSI as it is not as stiff a ride? On the inside of the drivers door has the tire specs unless you have changed to something that is not OEM..Jim

Same truck as yours. I drive daily and also tow 33 ft 9klbs travel trailer 55\70 (oe tires)

Loaded: 60 Front, 80 Rear
Unloaded: 60 Front, 55 Rear
Tires have worn even. Ride is highly improved and wet weather handling has been great for this type of vehicle!

My trip this weekend, I ran 75 rear and 68 front. They ride well and stay cool. Check your tires at stops for temperature.

God I love tire pressure posts! :D Definitely "Quad A" material! ):h

The front axle on our diesel (not gas) trucks carries around 4400 lbs unloaded at all times, rear axle 3000 lbs+-, yet we tend to under-inflate the front tires and jack up the rears both when towing and not towing! :confused: Unloaded the majority of the vehicles weight and approximately 70% of the braking load is on the front tires. This can be dangerous, also you'll eat tires up much faster. :o: Unloaded I run 65psi minimum year round on the front, 50-60psi rear depending upon the time of year. Yea, the rubber/sidewalls are harder during cooler weather so I adjust for that. :D The front tires have a soft suspension so the extra tire pressure is hardly noticeable. The rears are another story altogether! ;)

As for towing, proper tire inflation is critical for several reasons, but most importantly for load range D and E tires. When towing anything of significant weight, say over 5k lbs, tires should be higher up in the psi range. Approaching max GVWR/GCWR all tires to include the trailers should be at max psi. A 80psi max tire inflated to 60psi can/will buckle the sidewall under emergent maneuvering while towing, physics stuff! ):h The sidewall needs the extra rigidity the higher psi gives them to function as designed. RF3? ;)

Good discussion. As always SAFETY FIRST!:ro) JJ :)

These are the OEM tires and according to a friend are the 8 ply. I check the pressure last Saturday or Sunday morning before taking my trailor (empty weight of 3000lbs) back to storage. The pressures were f/r 54/51 and not knowing for sure I put them at f/r 55/55.
Sounds like I need to take the fronts up to 60 and leave the rears alone for Daily Driving.
Thanks for all the info.
Ray

Ray,

To echo the others, and add a little to it....

On/Off road tires are a slightly different animal than the "road tractor" type of tires. Your door jamb "tire pressure" tab indicates "optimum" pressures for 50/50 on/off road applications. Towing becomes more complicated, and there is no rule of thumb that applies to all tires. The key is know your scaled weights on each axle, then use your tire manufacturer's recommended pressures from their chart. You will find that you may have to add 50 Psi to the drive tires when the fiver is on, and have to take out 50 Psi to do off-roading, to deal with the sidewall flex. Too much flexing due to heavy vertical load will cause heat and can delaminate the sidewall plys. On the other hand, not enough flexing while rock-hopping off-road and you can end up splitting a sidewall due to not enough sidewall flex.

As I've said before (and done it myself), the perfect tow vehicle is a poor off roader, and the perfect rock-climber is a poor tow vehicle because of tire selection and the articulation designed into the different suspenssion systems. Your "stock" pick-up was designed with compromises to be able to do both reasonably well.

RF.

I've never seen an HD with D range tire. Could be a switch made at the dealer. I don't think you can reach your GVWR with 8 ply tires. The specs call for 245/75/16E "but" most 265/75/16D have the same rating as the 245s. I went with the 265/75/16E for the extra 800lbs they can handle. I think 60 psi is the max for 8 ply tires. Be very carefull with your load rating.

Just keep in mind your tires max load rating is for max psi, and moves down with psi on a sliding scale..
For our stocker 245's;

3042lbs at 80 psi

2900lbs at 75 psi

2765lbs at 70 psi

big difference for just 10 psi

I run 55/55 unloaded and 60/80 loaded (2650# pin weight). I've been doing this for years on two 2500HD trucks. This is with stock LT245 75R 16E tires.

2004 2500HD LLY D/A CC/SB - Husky 16K Slider
Montana 3685 FL - 14K ready to roll
2002 2500HD LB7 D/A EC/LB Reese 16K

My 285's are a "D" range, and are listed on the sidewall to be 3305#s at 65 PSI. With my 5'000# camp trailer, I air them to 50 PSI all the way around, this is with a weight distributing hitch. Any opinions on this? Just curious.

I can tell you that at 55psi your loadrange for the 285's is 2925lbs. It drops about 200lbs for every 5psi down from 65psi.