Dually tire pressures - different PSI for improved wear?

[JSellers]

I just got new tires, and had a friend suggest that dual rear tread will wear more evenly with less pressure in the outers. He suggested about 10PSI less in the outer tires.



Before tire purchase, I have noticed that my outer rears wear faster. Or could it be my imagination? The only thing I can guess is the outer tires may scrub more in turns. Could there be any help with this differential pressure between inner and outer dual rear tires?



Can anyone lay some verification on this? Do you run the same pressures in your duals? Or different? Less or more in the outer tires?



Of course, this might be subject to revision if hauling or towing... .



Thanks,

John

 

[gwagner]

I run the same pressure in mine havent had any problem with it. just rotate and balence and them at regular intervals and keep them alined. And you shouldnt notice any difference in wear.

 

[Cattletrkr]

I do run mine lower, but all of them the same. I do this 'cause I'm only running loaded one way. Tires are slightly underinflated loaded, but are still overinflated empty. I've managed to even out my wear patterns by doing this. My factory tires I ran at about 70psi in the rears and 72-3 in the fronts. Seemed to work well. With the 19. 5's I've been running around 70 in all six. Still wearing a little more in the center, but not bad. I don't wanna go under 70 for those inevitable heavier than expected loads. I've never blown a tire on the truck in 200K+ of doing this.



I never used to rotate the fronts in with the rears 'cause the rears would wear out so fast I'd have to rotate every 4K or so, yuck. With the 19. 5's I rotate every 10K and that seems about right. All 6 are wearing about the same.



I don't like the thought of running lower pressure in one tire on the dual. I have had outer tires wear faster, but not a significant amount. Adjusting pressure based on load has worked better for me.

 

[JSellers]

Thanks for the responses, guys.



I should have included - I spent money for Alcoa wheels with the new tires. So, rotation now demands that I break the tires off of the wheels to move them around. My rear tires have worn more than the front, and the outer rear tires have worn faster than the inner ones. I was hoping there might be something to this "pressure differential thing" - to even the wear between the rear duals. Thinking that it might add a bit more mileage before having to rotate.



I don't tow regularly, nor do I haul heavy loads - maybe I should leave some weight in the bed.



Anything to even the tire wear... .



Regards,

John

 

[Cattletrkr]

What presure are you currently running in the rears? Empty you should be able to go way down, easily 60psi or so. I've never been a big fan of running on low psi, but an empty dually should be OK. Check with your local tire shop though just in case there's a minimun psi for your tires. Don't wannt be spinning that sucker off the rim pulling out at an intersection.

 

[Turboman]

You need to have equal pressure in both tires. With a loaded truck, if you have one tire as little as 10 psi less, that lower tire will not be as big diameter and will actually be scuffing or dragging down the roadway as much as 13ft every mile. Think what that does for tread wear. Now empty, it may not be as drastic and also these numbers are class 8 truck numbers but the concept is the same.

 

[Wiredawg]

40 psi in rears empty

I don't rotate mine but about every 10K to 15K miles. I run 40 psi in rears and 65 psi in fronts. Lower pressures in the rears prevent wearing in the middles. My truck weighs 9. 6K. you can weigh your truck and take the rear weight divided by the total weight rating of the four tires. Take the derived fraction and multiply by 80 psi. The resulting number is the ideal tire pressure for the weight. My number came out to 36 psi, but I round it to 40. Ideal weigh preassure for front came out to 54 psi, but 65 wears better. I air them up to 80psi when towing the 17K lb 5th wheel.



At 65K miles w/ 35% tread, I swapped tires w/ my 5th wheel (tripple axle, same size tires). Had about 20K miles on the 5th wheel.



Wiredawg

 

[DennyDay]

If you run mostly on two lane roads, I think you will find you get more even wear on rears if you run 5 psig less on the inside tires. Will handle a little better too.



Denny