HD Tire Pressure Observations

[HEMIMANN]

Anybody else find their HD truck rides better at full tire pressure without a load?

At least for the 2500 (3/4 ton), which has 5 link rear coil suspension instead of leaf springs?

This is the only truck I've owned with the rear suspension like this, and the only truck where full load tire pressure all the time rides better. With all the other 3/4 ton trucks I've owned, all which had conventional leaf springs, the truck rode like a dump truck empty if the tires were aired up all the way to full load carrying capacity. I used to have to air the tires up and down all the time.

Outside temp dropped from mid 80's to mid 40's for high temp in only a couple days, and the truck started bouncing and squirming. Tires were 8 psi below full load rating (full load rating 65 psi front, 80 psi rear). I aired them up and the truck rides and turns perfectly again.

This is convenient, but weird to me. I originally griped about Ram TPMS low pressure warnings, but now I don't need to find delete software.

Thoughts? Comments?

 

[olyelr]

Running the tires at max psi when empty is crazy…way too much air. You will start wearing out the center of the tire tread and the outsides will be like brand new. And the fact that it rides better in your opinion is even crazier…thats hard to believe!

 

[Green_Manalishi]

Mine rides rough with 65/80. When not towing/hauling I keep it at 55/55 and ignore the TPMS.

 

[06 Dodge]

Not sure what tire size you have but my 06 4x4 2500 CTD with 265/70/17, the winter tires I would run 60 psi FT, 55 psi R, in the summer tires ( the stock Michelin tires) unless towing I ran 65 psi in all 4 tires for the 13 years it was in northern IA, my tire wear was always within 1/32 front to rear at every rotation, in my 22 2500 4x4 CTD with 275/70/18 it calls for 60 psi in all 4, so to me your rear at 80 psi empty seems a bit over inflated...

 

[mtofell]

I Run 60 front 80 rear all the time and have no complaints. Sure, it's stiff but as @HEMIMANN points out the coils are quite a game-changer over leaf suspension. Driving day to day it's hard to remember but when I got my truck I came out of a Chevy HD and remember how pleased I was with the coils. I just loaned my truck to a buddy that has an HD Chevy and he commented on how different and great it felt. It was nice reminder of how/why I love the coils.

 

[tjfdesmo]

Definitely not my experience when I had my '15 2500.

 

[HEMIMANN]

Running the tires at max psi when empty is crazy…way too much air. You will start wearing out the center of the tire tread and the outsides will be like brand new. And the fact that it rides better in your opinion is even crazier…thats hard to believe!

TPMS low air warning software comes on @ 55 psi front and 70 psi rear. I called Mopar service and they said that is correct, not way too much.

 

[HEMIMANN]

Not sure what tire size you have but my 06 4x4 2500 CTD with 265/70/17, the winter tires I would run 60 psi FT, 55 psi R, in the summer tires ( the stock Michelin tires) unless towing I ran 65 psi in all 4 tires for the 13 years it was in northern IA, my tire wear was always within 1/32 front to rear at every rotation, in my 22 2500 4x4 CTD with 275/70/18 it calls for 60 psi in all 4, so to me your rear at 80 psi empty seems a bit over inflated...

LT285/60-R20

 

[tjfdesmo]

TPMS low air warning software comes on @ 55 psi front and 70 psi rear. I called Mopar service and they said that is correct, not way too much.

My 2015 only put about 3,200 lbs(?) IIRC on the rear axle when empty, so if you consult the tire manufacturer load table, you'll find 70 psi is way beyond what's needed. Those low-pro tires aren't helping, either.

 

[Dean2]

I have the OEM 18" rims with Duratrac 275/70/18 tires on my 2021 2500, long bed. I run 45 rear, 50 front and find it rides much better with a lot less air. From 65 rear to 55 rear, no real difference. Ride didn't improve much till I aired the rear down to 45. I used Alphaobd to fix the TPMS.

LT275/70R18 Goodyear Duratrac Tire Pressure Chart​

Corresponding tire load capacity at specified tire inflation pressures for LT275/70R18 tires.

 

[olyelr]

TPMS low air warning software comes on @ 55 psi front and 70 psi rear. I called Mopar service and they said that is correct, not way too much.

Well they are wrong. Running max pressure, or even 70 psi in the rear of an unloaded truck is just crazy. It should be considerably less than the front air pressure…there is a lot less weight back there then in the front.

 

[mtofell]

Well they are wrong. Running max pressure, or even 70 psi in the rear of an unloaded truck is just crazy. It should be considerably less than the front air pressure…there is a lot less weight back there then in the front.

Yeah, the government, manufacturer's, etc. assume a loaded truck... and don't give us enough credit to realize we have loaded our truck and should put more air in our tires. Thank your lawyer!

 

[olyelr]

This will be the outcome for tire wear when running them at max psi when unloaded…

 

[mtofell]

This will be the outcome for tire wear when running them at max psi when unloaded…

View attachment 529766

I've got 120K miles on my truck and just finished my third set of tires running 60psi front 80psi rear the entire time, unloaded 95% of the time and my tires wore perfectly evenly... nothing even close to those pics.

 

[HEMIMANN]

Well they are wrong. Running max pressure, or even 70 psi in the rear of an unloaded truck is just crazy. It should be considerably less than the front air pressure…there is a lot less weight back there then in the front.

Feel free to call their engineers and tell them they are wrong based on your extensive engineering analysis of tire and suspension design.

 

[jejb]

I've got 120K miles on my truck and just finished my third set of tires running 60psi front 80psi rear the entire time, unloaded 95% of the time and my tires wore perfectly evenly... nothing even close to those pics.

I've had several 3/4 tons over the years, and my experience is the same. Good 10 ply tires wore evenly even though they were "over inflated" when not towing. I have started to air them down on my 22 2500 since the door sticker says 60/60.

 

[HEMIMANN]

I've had several 3/4 tons over the years, and my experience is the same. Good 10 ply tires wore evenly even though they were "over inflated" when not towing. I have started to air them down on my 22 2500 since the door sticker says 60/60.

That's weird. Wonder why they changed.

 

[62Blazer]

When I first read the topic I thought it was crazy.......but read the details of the original post and think it's even crazier! It's talking about the tire PSI difference simply caused by a drop in ambient air temperature from 80 to 40 degrees which caused the PSI reading to change by 8 PSI. And they stated it makes a big difference and causes the truck to bounce and squirm a lot? Just very surprised that going from 80 PSI to 72 PSI caused a noticeable difference at all. From my personal experience I have never experienced this. I've noticed handling getting squirmy with significantly lower pressure, like going from 80 to 40 psi.

 

[Dusty]

Anybody else find their HD truck rides better at full tire pressure without a load?

At least for the 2500 (3/4 ton), which has 5 link rear coil suspension instead of leaf springs?

This is the only truck I've owned with the rear suspension like this, and the only truck where full load tire pressure all the time rides better. With all the other 3/4 ton trucks I've owned, all which had conventional leaf springs, the truck rode like a dump truck empty if the tires were aired up all the way to full load carrying capacity. I used to have to air the tires up and down all the time.

Outside temp dropped from mid 80's to mid 40's for high temp in only a couple days, and the truck started bouncing and squirming. Tires were 8 psi below full load rating (full load rating 65 psi front, 80 psi rear). I aired them up and the truck rides and turns perfectly again.

This is convenient, but weird to me. I originally griped about Ram TPMS low pressure warnings, but now I don't need to find delete software.

Thoughts? Comments?

Could this be the result of the particular tire brand that's currently on it?

My son seems to think his 2014 2500 with Coopers ride much better with reduced tire pressure.

Regards,
Dusty
2019 Ram 1500 Billet Silver Laramie Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33-gallon fuel tank, 18” wheels. Build Date: 3 June 2018. Now at 99687 miles.

 

[Gr8bawana]

I can only speak from my experience with my 2017 2500 Cummins. When I first got the truck the tires were inflated to 70 front and 80 rear, holy crap. It felt like there was no suspension at all.
I now run the stock size 275/70/18 tires at 60 front and 50 rear when unloaded. The difference is like day and night.
When towing our 14k 5er I do inflate rear to 80psi and front to 70psi.
My BIL keeps his tires inflated to 80psi all the time and they look like those posted earlier, worn in the center. I tried to explain why that is but he wouldn't hear it.