At what pressure do you run your "Truck" tires ???

J-W&E

Well-known member
We have a Dodge 3500 dually. What tire pressure do you run when towing?? What pressure do you feel gives you the best gas milage when towing? Steering tire pressure ??? and rear dual tires??
 

kerry

Member
Tire Pressure

I run the maximum tire pressure stated on the tires cold, everything runs and tows better

Kerry
3400RL Bighorn
 
K

Ken Washington

Guest
I don't like a ruff riding truck! I run about 55 lb. all around and have no problems. When tires get hot, the preasure goes up so I would not put them to the max. If you run too much preasure or too little, you will be buying tires before you need to. I keep a good eye on wear and rotate often. Get a good starting point and go from there.
 

ct0218

Well-known member
True, it will ride a little rough, BUT, the maximum load a tire will carry is at maximum inflation. Less air means less capacity, and with the weight of these units you will shorten the life and possibly damage the tire by running them at max load with low air. Your best mileage will be at max air, and when underinflated the tire is less stable because the sidewall flexes more. When towing, max pressure, deflate to what KW uses when solo, then reinflate when hitching back up. Carry a small but sufficient pump with you and your tires will last longer, and you will be safer.
 

phranc

Well-known member
If max cold pressure is 80 lbs ,then thats what I run, Dodge single rear wheel..
Trl has 'G' rated tires and I use 110 lbs.. So far it works for me..
 
K

Ken Washington

Guest
This question is not as easy as it sounds. If you are not maxing out your pay load weight ( what you would carry in the bed ) then why would you have to run max preasure? My tires says 2470 lb. for dual tires times two at 80 lb. which would be 4940 lb. The pin wt. on my trailer is about 2500 lb. which is not max. I think that when my tires warm up, they are at about 62 lb. and it runs rock solid. I know that when I had a 2500 SWR , I was up and down with preasure all the time. I may be wrong, just asking!
 

ct0218

Well-known member
You're right, it's not simple. Have you weighed your fifth wheel and truck? I am surprised that you only added 200 lbs to the tongue weight with your normal load. The GC has about 2300 lbs tongue weight from the factory with standard equipment. The options will add weight to that number, and if your gross trailer weight is 15k, you would be around 3000 tongue weight (20%). If your tires are at maximum air they will support x lbs ea times 4, then subtract the weighed rear axle weight of the truck. Part of that tongue weight is carried by the front axle also, and with the Duramax engine you are at or over the front axle capacity. It's really marginal on the Chevy/GMC front axle we have. The only way to know is to weigh the whole rig, and most people I know have underestimated their weight. I ran across a chart one time that listed the carrying capacities at different inflation pressures and it seemed to drop substantially if the pressure was reduced. I just can't remember where I found it. There are axle ratings (GAWR), gross vehicle weight ratings (GVWR), and gross combination weight ratings (GCWR). Most of us are at or over at least 1 of those. The truck will handle it, and there are many pulling much heavier loads than these, but the weak link is the tires. Weigh the whole rig, as you would be driving down the road on a trip (fluids, toolbox, etc, and you and the family in it), then check your axle weights on all 4 axles. It surprised me! As I posted this I saw the post by Jeff 11-11-2004 just below this thread. At 55 lbs inflation the capacity of the tires you have on a dual application is about 1865 lbs, which is a drop of about 605 lbs per tire, or 2420 lbs less capacity on the rear axle alone. I run 55 in the rear empty, but adding 3000+ pounds to the bed would have to overload the tires.
 
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K

Ken Washington

Guest
Hi CT0218,
Thinks for your input on this matter. I am thinking obout an increase in preasure, just don't know how much. When I hook up now at 55 lb., I see little change in the tires but I know that appearance is not everything. I hope that J-W&E got the info. that he needed out of all this!
 

kerry

Member
tire pressure correction

I posted earlier I run max air on my tires by what is on the tires.. I run max air pressure by what is posted on the driver's door post. Rear wheel pressure at max load is different on SWD vs DWD. Dually's typically don't run max tire pressure

Kerry
 

arisce

Well-known member
I agree with kerry. I go by what is posted on the door. I have a dually. On the door the tire pressure is given for SWR and DRW. I asked my dealer what to do. They said to always go with what is posted on the door. These recommendations are made according to the specification of the truck and not the tire. Tire reads 80 max door reads 65 max. I put 65 max when pulling.
 

J-W&E

Well-known member
Thanks everybody for your help.....

We run our DRW when pulling at 65 rear and the front at 60. The truck door post states 65 as max. This is what the Dodge dealer suggested. I think we will try the weighing as stated above to see what that would suggest.
 

fireflipper

EX-Travel Bug
Fireflipper

Just a quick line here. The pressure should be set by what the tire manufactuter recommends according to the wieght thath is being carried. That being said you need to weigh each axle when loaded, including passengers, than go to the tire manufacturers web site and see what pressures are recommended for your tire size and rating. If you can not find a website, contact a tire dealer and they should be able to tell you the different pressures for the amount of weight on the tire.
 
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