Silverado 1500 tire pressure when towing

[malibu43]

I just got Nitto Ridge Grappler LT275/60r20 (E rated) tires on my 2021 Silverado 1500. This is the stock tire size for my truck, although stock were P-rated instead of LT. The sticker on my truck says 34-36psi cold. The tire shop inflated the new tires to about 38 psi, max psi for the tires is 80 psi.

What should I inflate these to for towing? Our trailer is 6440lbs max weight, and let's assume my truck is at max payload when loaded for a camping trip (7100lbs) and assume it's evenly distributed (I know, big assumption). That's 1775lbs per tire.

I'll be towing about 1K miles for our 4th of July camping trip, so want to get it right.

Thanks in advance!

[jadatis]

That asuming is dangerous, only save way to determine axleloads is by weighing fully loaded and trailer behind.

Once you determined the axleloads, or better axle-end loads 99% accurate, wich is your responcibility, you can use my made pressure /loadcapacity list with build in maximum reserve, but still acceptable comfort and grip.

Need next from your tires to make such a customused list.

1. Maximum load or loadindex
2. Loadrange, your E-load AT 80 psi, but lately saw exeption to that rule of 65 psi for E-load. So try to find AT 65 or 80psi on sidewall.
3. Speedcode, less important, will be Q or more.

For your trailertires I also can make a list.

E-LOAD needs about 15 psi higher then for standard load P-tire calculated of same sizes, for same load.

But nowadays often AT-pressure of P-tire is given of 35 psi as recomended pressure, and if calculated it could be as low as 28 psi, so then E-load about 43 psi.
Then the 38 psi is probably yust needed for normal use, at wich axleloads are lower then GAWR's.

[jadatis]

Found with Google E- load in loadindex 119/ 2998 lbs saw P-tire wich always AT 35 or 36 psi, loadindex 114/2601 lbs maxload.
So this small difference makes me suspect E-load to be that exeption to the rule, so AT 65 psi.

This then needs about 10 psi higher pressure for the same load.

So you have to look on sidewal, mayby not even E-load.

[wiredgeorge]

Your truck came with passenger car tires (P rating). Since you changed to LT (light truck) tires, the tire placard isn't relevant. I suggest the max PSI on the sidewall of 80 PSI is what you should air your tires to when towing to take advantage of their full load handling capability.

[Max23]

Agree with George. If your putting them under a heavy load,they are designed for that at max pressure. To low and your hurting the sidewall structure of the tire.

[notanlines]

I agree with George and Max. Start at 80 because of what it says on the tire itself. I certainly wouldn’t go below 65 for any reason.

[rhagfo]

Originally Posted by wiredgeorge

Your truck came with passenger car tires (P rating). Since you changed to LT (light truck) tires, the tire placard isn't relevant. I suggest the max PSI on the sidewall of 80 PSI is what you should air your tires to when towing to take advantage of their full load handling capability.

Originally Posted by Max23

Agree with George. If your putting them under a heavy load,they are designed for that at max pressure. To low and your hurting the sidewall structure of the tire.

If you want to ride on rocks sure inflate to 80 psi, if you want a solid ride and not rocks inflate to no more than 65 psi. The four tires on out DRW are E rated and max 80 psi, and load chart is 65 psi for the four tires to carry 9,750#, we are not at max axle, so run at 55 psi. If you inflate to 80 psi they will be rocks.

[jxnbbl]

Agree with all of this, assuming the rims max psi is within the range.

[jadatis]

Googling again the size 275/60R20 in XL, I also found 119 loadindex, but also 116 loadindex.
So tiresellers cant also be trusted to give the right information, what is on the tire must be right.

So it yust as wel could be that you find XL/reinforced/ Extraload on sidewall.
Then maxload of 2998 lbs is carried upto 99mph AT 42 psi.
Then no LT in front, and also not P, because european system.

I will wayt for your information, before I make the list.

Putting on 80 psi comes from the Traveltrailer world, in wich mostly yust enaugh maxload to cover the GAWR's, and often maxload for 65mph given, so need often even more then 80 psi cold, to give the absolutely needed reserves for unequal weight R/L and speed.

[CWtheMan]

A new recommended inflation pressure needs to be established for the LT tires. The minimum is required to be a PSI inflation that will cause the tires - at the very minimum - to provide a load capacity equal to or greater than what the "P" tires provided. Once the new recommendation is established, a supplementary (homemade) decal may be placed next to the vehicle certification label.

[wiredgeorge]

Originally Posted by CWtheMan

A new recommended inflation pressure needs to be established for the LT tires. The minimum is required to be a PSI inflation that will cause the tires - at the very minimum - to provide a load capacity equal to or greater than what the "P" tires provided. Once the new recommendation is established, a supplementary (homemade) decal may be placed next to the vehicle certification label.

How would one achieve a self-rating for tire pressure without specialized equipment that is capable of measuring the load capacity that the P rated tires had. The P rated tires were passenger car tires and now the OP runs LT tires (LRE). Why go through all these exercises? I am pretty sure that at 80 PSI he will have sufficient load capacity and then air them down when not towing. These tire threads add a huge amount of unnecessary confusion for folks asking a simple question.

[malibu43]

Originally Posted by jadatis

That asuming is dangerous, only save way to determine axleloads is by weighing fully loaded and trailer behind.

...

Thank you jadatis for the very detailed response. I'd like to get my truck/trailer fully loaded on a CAT scale, but I haven't had the chance. I don't have one close to me, and I've never had time on a road trip to stop and use one. We might have a little more time on this upcoming trip, so I'll see if I can stop and use one.

Originally Posted by wiredgeorge

Your truck came with passenger car tires (P rating). Since you changed to LT (light truck) tires, the tire placard isn't relevant. I suggest the max PSI on the sidewall of 80 PSI is what you should air your tires to when towing to take advantage of their full load handling capability.

Thanks for this wiredgeorge. This is similar to the answer I got at Discount Tire when I got the tires yesterday. The guys said he couldn't say what the correct pressure for my setup would be, but he said normally when customers come in to have a 1/2 ton aired up for towing, they go with 80psi rear and 65psi in the front.

[jadatis]

Originally Posted by wiredgeorge

How would one achieve a self-rating for tire pressure without specialized equipment that is capable of measuring the load capacity that the P rated tires had. The P rated tires were passenger car tires and now the OP runs LT tires (LRE). Why go through all these exercises? I am pretty sure that at 80 PSI he will have sufficient load capacity and then air them down when not towing. These tire threads add a huge amount of unnecessary confusion for folks asking a simple question.

Better making a simple question complicated, then having tire failure by to low pressure, or in this case mayby to high pressure
Mayby TS tires apear to be XL, AT 42 psi, and then 80 psi is way to high.

The tires you can check now, dont need a scale for that, only the tires.

[sourdough]

OP lots of info. My simple mind tries to keep things simple. You've got a lot of tire sitting under that 1500 which is good for towing a heavy RV IMO, not so good driving over speed bumps taking the kids to school. Also keep in mind the softest thing between you and those tires is your suspension. Those tires aired up to 80psi won't hit you in the back like a sledgehammer as they would on a stiff sprung 1 ton....it will be different.

Some thoughts that occur; you did not give your gawrs. What is the rear? I also didn't see a payload number? Those tires you have are rated at 3750lbs. at 80psi. - way stout for a 1/2 ton. At 65 psi they are 3195lbs. Just some perspective. The trailer gvwr of 6449 at 13% for tongue weight is 837lbs (no scale weights). - a little more perspective.

IMO in a nutshell is run the tires at 80psi initially to see what you have with the trailer. The weak links will be above the tires weightwise. It won't hurt anything and will take care of that trailer. Without the trailer it's going to be considerably harder riding than the P tires but that will be the case at 80psi or 50psi....the sidewalls are like concrete compared to the squishy sidewalls of a P tire. You can air down but you will never have the ride of a P tire....which is good. A truck shouldn't have P tires IMO.

Another way to look at those LT tires; if you max your gvw on the truck as you mentioned, and you had 1775lbs. per tire (you won't, the load won't be distributed that way) the tires at 80psi will support 3750lbs. Subracting that 1775 still leaves you 1975lbs, per tire, surplus in the rear. If you figure the weight was distributed differently and you had 2175 lbs. per tire (truck alone) you would still have 1575lbs., per tire, surplus. Then you would subtract the 837 tongue weight (418.5 lbs per tire) from that 1575 leaving about 1157lbs. excess per tire.

Lots of "perspective" there. You don't have much time to trial and error between now and July 4. Start at 80 and adjust. I gave you the weight bearing of 65 or 80psi. Both inflation levels will be fine. If you take a compressor with you (and you certainly should) you can air down on the far end and experiment with different unloaded pressures to find a spot that's more comfortable (you may be able to do that before leaving). Just some food for thought.

Edit: Correction! The rating for that size tire at 80psi is 3415lbs. not 3750. My eyes must have dropped down to the 275/65R20 size. The calculations I posted above would need to be adjusted.

[fjr vfr]

Find your tires here:
https://dcadprod.azureedge.net/b2b-e...rt-may2021.pdf

You can run at 80psi but for your load I think it's a little to high. I would run something like 60psi front and 70psi rear. That will give you more than enough capacity for what you're towing and load.
Also one more very important point, rubber valve stems are rated to 65psi max. If you run over that pressure you will need solid core valve stems.
Also check your rims for their rating. It should be stamped on the inside back of the rim.

[rhagfo]

Originally Posted by sourdough

OP lots of info. My simple mind tries to keep things simple. You've got a lot of tire sitting under that 1500 which is good for towing a heavy RV IMO, not so good driving over speed bumps taking the kids to school. Also keep in mind the softest thing between you and those tires is your suspension. Those tires aired up to 80psi won't hit you in the back like a sledgehammer as they would on a stiff sprung 1 ton....it will be different.

Some thoughts that occur; you did not give your gawrs. What is the rear? I also didn't see a payload number? Those tires you have are rated at 3750lbs. at 80psi. - way stout for a 1/2 ton. At 65 psi they are 3195lbs. Just some perspective. The trailer gvwr of 6449 at 13% for tongue weight is 837lbs (no scale weights). - a little more perspective.

IMO in a nutshell is run the tires at 80psi initially to see what you have with the trailer. The weak links will be above the tires weightwise. It won't hurt anything and will take care of that trailer. Without the trailer it's going to be considerably harder riding than the P tires but that will be the case at 80psi or 50psi....the sidewalls are like concrete compared to the squishy sidewalls of a P tire. You can air down but you will never have the ride of a P tire....which is good. A truck shouldn't have P tires IMO.

Another way to look at those LT tires; if you max your gvw on the truck as you mentioned, and you had 1775lbs. per tire (you won't, the load won't be distributed that way) the tires at 80psi will support 3750lbs. Subracting that 1775 still leaves you 1975lbs, per tire, surplus in the rear. If you figure the weight was distributed differently and you had 2175 lbs. per tire (truck alone) you would still have 1575lbs., per tire, surplus. Then you would subtract the 837 tongue weight (418.5 lbs per tire) from that 1575 leaving about 1157lbs. excess per tire.

Lots of "perspective" there. You don't have much time to trial and error between now and July 4. Start at 80 and adjust. I gave you the weight bearing of 65 or 80psi. Both inflation levels will be fine. If you take a compressor with you (and you certainly should) you can air down on the far end and experiment with different unloaded pressures to find a spot that's more comfortable (you may be able to do that before leaving). Just some food for thought.

Absolutely no reason to run E rated tires at 80 psi on a 1500!!
At 80 psi, load rated of 3,750# ea. so total of 7,500# of load carrying capacity on likely a 3,900# rear axle. As stated driving on “overinflated” tires, reducing the tread contact area reducing traction!
The max should be 65 psi IF your rims are rated for that pressure.
Just because the tire has a max pressure of 80 psi doesn’t mean you need to run them at that, if you do traction and handling will be affected especially in wet conditions!
Stop and think about this the tires on my 2016 RAM 3500 tires are each rated at 3,085# single, 2,835# in DRW configuration and my payload sticker states 65 psi for the four tires to support 9,750#. Do you really think you need to inflate them to 80 psi for your 1500???

[wiredgeorge]

Originally Posted by fjr vfr

Find your tires here:
https://dcadprod.azureedge.net/b2b-e...rt-may2021.pdf

You can run at 80psi but for your load I think it's a little to high. I would run something like 60psi front and 70psi rear. That will give you more than enough capacity for what you're towing and load.
Also one more very important point, rubber valve stems are rated to 65psi max. If you run over that pressure you will need solid core valve stems.
Also check your rims for their rating. It should be stamped on the inside back of the rim.

Truck rims have a max PSI stamped on the back? Didn't know that.

[CWtheMan]

I have provided the industry steps of procedure to establish a minimum recommended cold tire PSI for the LT tires.

The "P" tires inflation chart will give the amount of load capacity they were providing at the vehicle manufacturers recommended inflation pressure shown on the vehicle certification label. A load inflation chart for the LT tires must be used to establish the correct inflation pressure for the LT tires.

Industry standards can be found in USTMA manuals.

Vehicle manufacturers have the sole responsibility for establishing recommended inflation pressures for original equipment tires. As users we use industry standards to mimic the load capacity the OE tires provide/provided.

[sourdough]

Originally Posted by rhagfo

Absolutely no reason to run E rated tires at 80 psi on a 1500!!
At 80 psi, load rated of 3,750# ea. so total of 7,500# of load carrying capacity on likely a 3,900# rear axle. As stated driving on “overinflated” tires, reducing the tread contact area reducing traction!
The max should be 65 psi IF your rims are rated for that pressure.
Just because the tire has a max pressure of 80 psi doesn’t mean you need to run them at that, if you do traction and handling will be affected especially in wet conditions!
Stop and think about this the tires on my 2016 RAM 3500 tires are each rated at 3,085# single, 2,835# in DRW configuration and my payload sticker states 65 psi for the four tires to support 9,750#. Do you really think you need to inflate them to 80 psi for your 1500???

I put those numbers there for a reason. I stated they were overkill. The OP said he didn't know and wanted to be safe. And, in all my driving, I've not found a tire running a skinny patch in the middle that would suddenly eliminate control....on a HD truck. They're not a P rated flimsy tire.

You've stated your situation with your tires on your 1 ton DRW...has nothing to do with the OP's 1500. My post, and others, are trying to give the OP some "perspective" as I said on his 6449lb. trailer and not your dually.

[rhagfo]

Originally Posted by sourdough

I put those numbers there for a reason. I stated they were overkill. The OP said he didn't know and wanted to be safe. And, in all my driving, I've not found a tire running a skinny patch in the middle that would suddenly eliminate control....on a HD truck. They're not a P rated flimsy tire.

You've stated your situation with your tires on your 1 ton DRW...has nothing to do with the OP's 1500. My post, and others, are trying to give the OP some "perspective" as I said on his 6449lb. trailer and not your dually.

Well the look at the OP’s truck, 7,100# GVWR each E rated tire has 3,750# capacity, or 15,000#, look at the rear axle likely 3,900# tow tires at 3,750# is 7,500 or 400# more than the trucks GVWR.
Sorry LT tires are not so stiff across the tread that over inflating by basically double, will result in less contact patch.
Yes, I used the term over inflated, as 80 psi they are way over inflated for load carried!