New TV tires today

[fallsrider]

I put new tires on our '05 Suburban today. Had the P tires removed, and Cooper Discoverer H/T LT tires installed. Now that my max. psi has gone from 44 to 80, what psi should I run in my tires for normal everyday driving? This is my daily driver.

The tire shop put 35 psi in them, but I'm wondering if that is enough. Maybe it is.

Then when towing our TT, what should I raise the psi to? I'm estimating our TT weighs in the 5,000 to 5,500 lb. range. Haven't had a chance to weigh it yet.

Thanks.

[FastEagle]

fallsrider wrote:
I put new tires on our '05 Suburban today. Had the P tires removed, and Cooper Discoverer H/T LT tires installed. Now that my max. psi has gone from 44 to 80, what psi should I run in my tires for normal everyday driving? This is my daily driver.

The tire shop put 35 psi in them, but I'm wondering if that is enough. Maybe it is.

Then when towing our TT, what should I raise the psi to? I'm estimating our TT weighs in the 5,000 to 5,500 lb. range. Haven't had a chance to weigh it yet.

Thanks.

Take a good look at this reference. When reading it, only apply the information that applies to your particular situation. Maybe you can figure out just what should have happened had you had a savvy tire installer.

Replacement tire reference

FastEagle

[B_O__Plenty]

Drive it for about 1,000 miles and give the tires a chance to break in. They will start to feel better and more more stable.

B.O.

[jadatis]

what Eluwak writes I also wrote , that its the responcibility of the tire-specialist, to put tires on that are allowed on the rimms and car.

the maximum load or pressure for the rimm is mostly written on the innerside of the rimm, so you have to take it of the car to read it.

What risks you take if you go over that , I dont know, but people yust as easy go over the GAWR ( gross axle weight rating)wich is also forbidden.
Probably there is some reserve over the pressure or maximum load written on the rimms, yust as it is for the technical axle maximum above the GAWR, but you cant build on that , and cant keep the manufacturers responcible, if something goes wrong because of going over it.

[eluwak]

Old-Biscuit wrote:
When you changed out those 'P' tires with MAX of 44# did you check what the rims MAX pressure is?

Upgrading to a higher rated tire doesn't do any good if rims are not rated for increase

I'm curious, has anyone ever looked at this and found that they couldn't upgrade the TV tires on a truck/van? If so, were they OE wheels?

I would think if a tire shop installed tires that would cause a wheel failure that it would be a liability for them.

[CapriRacer]

fallsrider wrote:
I put new tires on our '05 Suburban today. Had the P tires removed, and Cooper Discoverer H/T LT tires installed. Now that my max. psi has gone from 44 to 80, what psi should I run in my tires for normal everyday driving? This is my daily driver.

The tire shop put 35 psi in them, but I'm wondering if that is enough. Maybe it is.

Then when towing our TT, what should I raise the psi to? I'm estimating our TT weighs in the 5,000 to 5,500 lb. range. Haven't had a chance to weigh it yet.

Thanks.

Boy, do I love tire threads. Lots of responses, lots of different answers, many of them wrong.

On every vehicle sold in the US, there is a vehicle tire placard that lists the original tire size and the proper pressure for that size. Vehicle tire placards are usually located on the driver's doorpost or in the glove box.

If your vehicle originally came with P metric tires (the tire size starts with the letter "P"), and you switch to an LT tire (tire size starts with the letters "LT") with the same dimensions (that is all the numbers are the same), then you need to use 15 psi more to get the same load carrying capacity.

If you are towing within the stated capability of the truck, then the placard pressure is what the vehicle manufacturer determined is the proper pressure for all conditions delineated there (or if they didn't list any restrictions or conditions, then that is what they want you to use for ALL conditions). A good idea would be to consult the vehicle owners manual for guidance.

If you are not towing within the stated capability of the truck, then I suggest you get a new truck - one that is capable of towing the load you want.

[jadatis]

When you switch from P-tires with pressure needed for the maximum load of 35 psi ( so is not the maximum pressure of 44psi written on sidewall ) to LT with pressure needed for the maximum load of 80 psi ( wich is written on the sidewall but is also not the maximum pressure of tire), you need higher pressure for the same load then the P-tire.
I estimate it to be even 10 psi higher, so 30psi old car advice +10 psi = 40 psi.
but you have to calculate it with my motorhome-tire-pressure-calculator.
Because the speed wont be higher then 99m/h you can use it.
If your back tires have a camber-angle of more then 2 degrees, wich you have to look up in the alignment data, that 80 psi has to be highened up with a system depending on the speedcode of the tire ( Q stands for up to 160km/99m/h maximum tire speed)
This maximum speed of tire has to be higher or the same as the technical maximum car speed by european law, dont know if America uses that law too.
So try to find that maximum speed of car and compare.
If your technical maximum speed of car is only 2 miles higher then that of the tires, by law you are not allowed them on your car.

Exception ( in Europe) is winter-tires, wich if lower speed it has to be warned for on the dashboard and only allowed between october and april.

But I asume the tire-specialist that fitted your tires, knows all this, and to my opinion fitting tires that are allowed on your car and rimms is their responcibility. That wont say that it cant be wrong, misyudgements are made even by specialists.
so look it up, and also about the maximum ( cold) pressure of your rimms or maximum load of your rimms, and determine if you have tires that are allowed on your car and rimms.

If you give the tire and car data here , I will calculate the needed pressure for you, regardless of if the tires are allowed on the car and rimm.

[Shavano]

Moved to Tow Vehicles

Moderator TT's

[time2roll]

If you put the front and rear gross axle rating into the tire load chart it will give the required pressure. I use 5 over the chart if using this method not to exceed other pressure limits.

[fallsrider]

smkettner wrote:
What does the door say? Same size just LT?
I recommend ~40 with maybe 50 to 65 in the rear when loaded and towing.
Did they install high pressure snap in or metal valve stems? Regular are good to 65 max.
Check the wheel rating before you go much over 50psi.

Door says 30 F&B. I think that is too low.

No high pressure stems. Didn't think to ask. Don't know about rims. Will need to check. I'll go no higher than 50 before I check.

[APT]

I ran about 38psi unloaded with LT D and LT E tires on my half tons. Towing and heavy loading was about 50 front/55psi rear. I recommend something around 50psi for your similar GVWR and axle weighted half ton Burb.

[time2roll]

What does the door say? Same size just LT?
I recommend ~40 with maybe 50 to 65 in the rear when loaded and towing.
Did they install high pressure snap in or metal valve stems? Regular are good to 65 max.
Check the wheel rating before you go much over 50psi.

[coolbreeze01]

35# from the tire shop empty is a good start. If it handles satisfactory, I'd leave it alone and air up for towing.
I run 80# rear and 70# front all the time. Enjoy your new tires.

[JJBIRISH]

Proper sidewall deflection is an important safety measure… all tires are designed with a static loaded radius (which is different than the tire radius)… that is the height from the(level) road surface to the center of the axle with its travel load on it… it maximizes the tires footprint on the road…

Weigh the truck and check the tires loading charts is the best and easiest starting point..

No scale, use the SLR measurement until you get a chance to scale it, If that measurement is to high you have too much air for the load… measurement to low you need to add more air to the tire… it puts you in the right ballpark to start with…

[Keith_Haw]

Just went through that with my 99 Ram 2500, and it sucked. I had P series tires running 55# all the way around and it handled towing great. Had new Cooper LT "E" series tires put on and aired them to the 55 front 80 rear like the door post says and couldn't keep it on the road. Kept stopping and dropping the air 5# at a time until I got it down to 60# in the rear and it handled a lot better. Still doesn't handle as good as the P series did but that might just be because they are new. Anyway, back to your question, I'd start at where you had your old tires set at and slowly increase the pressure. Of course if you want to spend the time you could always do the chalk check. Draw a line all the way across the tread on the tires and add/remove air until the line is completely gone. More air if it wears on the outside first, less if it wears in the middle first. When it wears evenly all the way across you have the tires inflated correctly for the load.