Tow Vehicle Tire Experts

[Valkdryver]

Tonight I installed a new set of General Grabber HTS XL's on our 2009 Dodge Ram 1500 with 20" wheels. My question is what should I be running for tire pressure in the front and rears? We pull a 2010 Shamrock 23SS. Should I reduce the pressure to factory specs when we are not pulling the camper?
Thanks for your help.

[Chuck_S]

The door jam pressure is only valid with the tires specified on it. Many times the replacement tires are different.

-- Chuck

[PAThwacker]

Not using the tires psi figures. I go by the 80PSI stamped on my door badge, right below the 2651lb payload stamp. PS. We snagged the mother load sub tonight: 2004 8.1 K2500 Center buckets, Sun and Sound, DVD with only 66k.

[Chuck_S]

I run factory data plate tire pressure on my Expedition. That's 35psi. I may run 40 psi towing if I think about it but unless I'm getting "radial squirm" it shouldn't matter. Max pressure listed on the tire is 44 psi.

Check your tire's temperature when towing. If they're heating up some extra pressure will cut some of the flex which is what causes the heat.

Maximum pressure noted on the sidewall is Cold Tire Pressure. They'll have much more pressure after they warm up on the road. Don't take air out, they can handle it.

-- Chuck

[Dtaylor]

QUESTION? Are you guys using the max pressure printed on the tire side wall? I assume you are not exceeding them, correct?

[PAThwacker]

Load range E shoes on my horse. 80psi!

[Chuck_S]

I have 10 ply on my 1/2 ton truck

I bet ya don't. 🙂

10 ply "rating" (Load Range E) sure. Meaningless number but plies were how tires were rated 80 years ago. And modern tires just use the rating and not the number of plies.

-- Chuck

[epeters]

I have 10 ply on my 1/2 ton truck. When empty and not towing, I run about 45lbs, towing I air rears to about 65 and fronts at 60. Seems to do quite well. Every rotation I have had good reports on wear.

[Helmsey]

Chuck&Gail wrote:
Scales are your friend.

Go weigh truck, full of gas and whatever, but as you use it NOT towing. Weigh front and rear axles seperately.

Hook up FULLY LOADED RV and fully packed TV and AGAIN weigh TV axles (seperately). Might as well weigh RV axles also.

Now get tire manufacturers charts which show optimum air pressure required for the load, and use those pressures.

+1

[Chuck_S]

The tire pressure on the door jam is for the factory fitted tires and is the pressure you need to meet the axle's weight rating. The factory tires may have a higher maximum pressure on the sidewall that will help keep the tire from flexing and heating but won't do a thing for your RAWR.

My Expedition factory rear tire pressure spec is 35psi but the original tires were rated up to 44 psi. Higher pressure seems to help squirm.

In other words the higher pressure may help the tires but not the axle or suspension.

-- Chuck

[Chuck_Gail]

Scales are your friend.

Go weigh truck, full of gas and whatever, but as you use it NOT towing. Weigh front and rear axles seperately.

Hook up FULLY LOADED RV and fully packed TV and AGAIN weigh TV axles (seperately). Might as well weigh RV axles also.

Now get tire manufacturers charts which show optimum air pressure required for the load, and use those pressures.

P.S. I add 5 psi for luck.

[dbbls]

Go by what the sticker on the door post states.

[PAThwacker]

I run 50 front 80 rear on our 2500 sub. Makes night and day with the rears aired up. I bounced down the road at 60psi and solid as rock at 80psi.