Tire Pressure Recommendations

[kdauto]

Personally, with a load range E 80psi max tire I will never recommend below 45psi, loaded or unloaded no matter what the chart says. You have a 1 ton truck, so expect 1 ton harshness up to a point.

Like I said, my happy medium is around 60-65psi rear, that way I'm not screwing around inflating rear inner dually tires and getting dirty all the time.

[Dave Pelletier]

Originally Posted by kdauto

Personally, with a load range E 80psi max tire I will never recommend below 45psi, loaded or unloaded no matter what the chart says. You have a 1 ton truck, so expect 1 ton harshness up to a point.

Like I said, my happy medium is around 60-65psi rear, that way I'm not screwing around inflating rear inner dually tires and getting dirty all the time.

Could you please say something stupid? ....I'm getting tired of agreeing with you all the time!

Dave

[kdauto]

Originally Posted by Dave Pelletier

Could you please say something stupid? ....I'm getting tired of agreeing with you all the time!

Dave

Hang around me long enough, I'm capable of plenty of stupid sh!t. At least, this is what the GF tells me...a bit too often for my liking.

[jadatis]

Originally Posted by Texas Sooner

Michelin Primacy XC tires - all six are LT235/80R17 120/117R TPC BSW

Then I trew it in my made extra safe calculator, wich gives highest pressure, so reserve, with still acceptable comfort and gripp.
Front 73 psi
Rear 28 psi !!!!
4 tires on rear
If you had
2 of those on rear, 54 psi.

Suprising, I realise but
2 front carry 2x 3086lbs= 6172lbs
My calc adds 10% to the 5120lbs on front axle, is 5632lbs , so large portion of the 6172 for 80 psi of the tires.

Rear 4x 2833lbs= 11330lbs , axleload 3900lbs
Only 34.5% of tires capacity.
You determined from list front 65psi , but no reserve added probably.
Rear 35psi is probably the lowest psi the list gave.
35 for dual gives most likely 1580lbs in your list.x4= 6350lbs


When towing axleweight rear becomes much more
Mayby more then front , but devided over 4 tires.

The 5120 lbs on rear dual, would need 38 psi.

Edit: read back and saw the P/lc lists you gave and checked them to be calculated with the bad old american calculation, still used for LT .
The European calculation for every kind of tire would give for 35 psi dual 1460lbs a tire, 120 lbs less.

[Kid Gloves]

Originally Posted by Texas Sooner

This is a very informative website - thanks for sharing!

Looks like you have all the information required for the weigh in. They’ll be able to guide you from there.

[wimpy]

Originally Posted by jadatis

Then I trew it in my made extra safe calculator, wich gives highest pressure, so reserve, with still acceptable comfort and gripp.
Front 73 psi
Rear 28 psi !!!!
When towing axleweight rear becomes much more
Mayby more then front , but devided over 4 tires.
The 5120 lbs on rear dual, would need 38 psi.

I can see potential tire rub on the dually tires at this inflation pressure. The tire mfgs. stopped doing recommendations due to our litigious society. Go by the vehicle mfg recommendations, if they say 80 as recommended, I'd not go below 65 psi.

[wimpy]

Originally Posted by Texas Sooner

Also, when I was looking for the DOT date codes on each tire I would only find them on two tires (photos with and without attached). The two that I could find them on have the same date (1022) so that tells me that they were manufactured during the 10th week (March 7th) of this year which makes sense since my truck came off the assembly line right after that.

FWIW, your tires, tire plant code 1M3=made in Greenville, SC

[Ray,IN]

I've since lost the reference, but back in 2002 when I towed with a Chevy Duramax dually with 16" LR E tires, the tire mfgrs. said to never run less than 45 psi in those tires. Their load/inflation charts did not display anything below 45psi.

[jadatis]

Originally Posted by wimpy

I can see potential tire rub on the dually tires at this inflation pressure. The tire mfgs. stopped doing recommendations due to our litigious society. Go by the vehicle mfg recommendations, if they say 80 as recommended, I'd not go below 65 psi.

The best calculation takes care that the deflection stays the same, so also the sidewalbulb.
So no rubbing.

[Kid Gloves]

Originally Posted by Ray,IN

I've since lost the reference, but back in 2002 when I towed with a Chevy Duramax dually with 16" LR E tires, the tire mfgrs. said to never run less than 45 psi in those tires. Their load/inflation charts did not display anything below 45psi.

FWIW: Michelin does publish an inflation chart with recommended pressures as low as 35psi for 16” LR E tires.

This also indicates, despite what was posted previously, that tire manufacturers do provide pressure recommendations. Some folks use this information when determining tire pressure for their vehicles, others blindly follow placard pressures and some come up with their own theories.

[Tireman9]

One thing to remember is that the pressure in the tables is the MINIMUM needed to support the stated load.

If you set to the MINIMUM inflation then you really need to check and adjust pressure every travel day as there is a good possibility the temperature will change and you will need to change the air pressure to compensate. You also need to compensate if you buy any "stuff" and carry it in the truck or RV.

Personally I do not like to be running at the limit of any component. I do not drive at engine Red Line but if you think running at the limit then I guess you can. I tend to run a + 10to +15% inflation on my cars. On my RV I run +20% inflation.

[Kid Gloves]

^^^As long as the +20% doesn’t put a tire over the Max sidewall pressure or over the Max rated pressure for the wheel, correct?

[FastEagle]

Tire inflation pressures are probably one of the most discussed topics in RV forums. Probably the best place to start is with the tire design. Tires are sold by size and load capacity. All tires are now referred to by their designated size. In this discussion, the designated size is LT235/80R17 with a load range E maximum load capacity. Their load inflation pressures can be found on any TRA approved load inflation chart for their designated size.

The recommended cold inflation pressures for those LT tires are determined by the vehicle certified GAWRs. The vehicle manufacturer is solely responsible for setting those inflation pressures for OE tires.

In the tire industry the vehicle manufacturer’s recommended cold inflation pressures are the very minimum value to be used. The tire industry standards are very simple; the minimums are displayed on the vehicle certification label, on the vehicle tire load placard and in the vehicle owner’s manual. No one in the industry is going to recommend less without an approval from the vehicle manufacturer.

It’s very important to remember that there are two acceptable sets of rules and regulations for tire inflation pressures. In this thread the discussion is about tires fitted to a Light Truck. The regulations, rules and industry standards come from NHTSA via the FMVSS standards and simplified by the USTMA standards. The other set of regulations and rules are for the commercial trucking industries FMCSA standards. FMVSA standards are not applicable with FMVSS standards.

The following paragraph is a verbatim statement from the USTMA light truck tire manual.

Proper Tire Inflation: The recommended inflation pressures for tires are typically measured in pounds per square inch (psi) and are indicated on the vehicle tire placard, certification label or in the owner’s manual. Never set tire inflation pressures below the recommended inflation pressure found on the vehicle tire placard, certification label, or owner’s manual.

[wolfe10]

Originally Posted by FastEagle

The following paragraph is a verbatim statement from the USTMA light truck tire manual.

Proper Tire Inflation: The recommended inflation pressures for tires are typically measured in pounds per square inch (psi) and are indicated on the vehicle tire placard, certification label or in the owner’s manual. Never set tire inflation pressures below the recommended inflation pressure found on the vehicle tire placard, certification label, or owner’s manual.

This can be viewed one of two ways:


Lawyer speak.


Engineer CYA, knowing that most Americans don't check their tires (hence the now standard tire pressure monitors/alarms that up the cost of every vehicle built) and wouldn't reinflate when going from empty to loaded.


So, IMO, they are correct in what they say, but a smart owner can do better.