LT265/75 16; C-ply....can I run at 35psi??.....

[Ramblin Fever]

Running this size tire on my Isuzu Rodeo; OEM tire psi specs are for a P225/75 16 @ 29 fr/32 rear psi.

I installed the 265's over 6mnths ago, Discount tire stated that it was in the best interest of the tires structure to be at nothing less then 40psi.

The tire is a Duratrac goodyear A/T 6-ply

Previous tires to this were bridgestone revo's same exact size/ also 6-ply, I ran them at 38psi forever.

IMHO, 40psi provides harsh ride, whereas 35-38psi is perfect for everything...would I be harming the tire to run at this level.

The max cold pressure, which I know is not something one should go by when setting levels, but it is stated at cold psi of 50 on the tires.

I'd venture to say this is a fairly heavy suv for it's size, with all the extra's we have on it.

 

[J. A. Rizzo]

Originally Posted By: Ramblin Fever
Running this size tire on my Isuzu Rodeo; OEM tire psi specs are for a P225/75 16 @ 29 fr/32 rear psi.

I installed the 265's over 6mnths ago, Discount tire stated that it was in the best interest of the tires structure to be at nothing less then 40psi.

The tire is a Duratrac goodyear A/T 6-ply

Previous tires to this were bridgestone revo's same exact size/ also 6-ply, I ran them at 38psi forever.

IMHO, 40psi provides harsh ride, whereas 35-38psi is perfect for everything...would I be harming the tire to run at this level.

The max cold pressure, which I know is not something one should go by when setting levels, but it is stated at cold psi of 50 on the tires.

I'd venture to say this is a fairly heavy suv for it's size, with all the extra's we have on it.


The OEM recommendation was for the OEM-recommended tires, which it sounds like are no longer installed on the car. If 35 feels comfortable, handles well, and the tires hold up OK for you, go with it. Is your gauge accurate?

 

[Bill in Utah]

LT tires require higher pressure. Why because if you run them lower the thicker belts wear worst and can over heat.

That's why I go with P tires on trucks that came with them and make sure I get the ones that can handle high pressure (some have a max tire pressure of 36-38 and others 44-48)

LT tires only if I need them or for off road-ing in rocks. But you pay for them with the ride.

Here is an excellent explanation of the issue.

Take care, bill

 

[Ramblin Fever]

P tires don't last on this truck...we do a LOT of offroading, and we live down a long muddy road...we also tow with this truck. I was replacing a tire every year on this truck when we ran P-metric because the sidewalls are a lot thinner and would tear at the slightest edge of a rock.

I used to barely get 25k miles out of a set of P-rated tires, I now get 50k easy....and not only that, there's a lot of excellent A/T tires that are not offered in P-metric.

When I ran P-metric, I ran them at 35psi with superb results; but I've also ran LT's at 36psi with superb results as well.

Just wondering if it's *ok* too without harming the tire structure.

 

[justinf89]

I have the same size tires on my truck. They are rated for 80psi but I run 40 in the rear for them to wear properly.

 

[ARCOgraphite]

Yo have to run the tires at a pressure which provides the best handling/traction/ride cvompromise. If its 35PSI then its 35 psi. I would hesitate going over 80MPH for long trip ( 1/2+ hour at speed) with truck tires underinflated though.

 

[Jim 5]

Originally Posted By: justinf89
I have the same size tires on my truck. They are rated for 80psi but I run 40 in the rear for them to wear properly.


I assume this is on your duramax. I have the same issue on mine, so I'm running mine at around 45 (rear) when I'm not towing our RV - trial and error basically. I might move to 40 if you've noticed this is the magic number. Although mine are on the 17" wheels. I actually had the TPMS thresholds lowered at the dealer so I could do this without the TPMS light illuminating on the dash.

 

[jmac]

Originally Posted By: justinf89
I have the same size tires on my truck. They are rated for 80psi but I run 40 in the rear for them to wear properly.


If your tires are rated for 80psi, you are not running C range, you are most likely running E range tires, ie. equivalent 10-ply tires. Due to loading, I never even consider putting C range tires on 3/4 ton and up.

 

[CapriRacer]

Assuming you have the original tire size and inflation pressure from the vehicle tire placard correct, then in order to carry the same load, an LT265/75R16 needs to use 32 / 37 psi.

I would maintain the split in pressure to preserve the handling balance on the truck.

 

[Ramblin Fever]

Originally Posted By: CapriRacer
Assuming you have the original tire size and inflation pressure from the vehicle tire placard correct, then in order to carry the same load, an LT265/75R16 needs to use 32 / 37 psi.

I would maintain the split in pressure to preserve the handling balance on the truck.


Sweet...thank you. Would that be 32 front/ 37 rear? Just want to make sure I have you understood.

 

[Bill in Utah]

Wow all of you ignoring ACTUAL photos using a heat sensitive camera of the DANGERS of under inflation of an LT tire.

I guess...

I'd NEVER suggest something that may hurt another person.

Bill

 

[4ever4d]

DO NOT UNDERINFLATE!(that much).The load range C tire and up will give a harsh ride by nature due to the heavier tread and carcass plies,not enough psi will cause heat build up and it can be significate.My many years of trucking taught me to be certain of proper inflation i have seen 22.5" load range G tires catch fire due to under inflation.I understand the weight difference between a p/u and a road tractor with 53'trailer but it's just not safe.I run my D load range tires on my p/u at 65psi and deal with the harsh ride othewise you would be better off with a smaller truck with P metric sizeing tires that ride better and you must have a need for a large truck or you would have gotten a smaller truck to begin with i'm sure.

 

[MNgopher]

Hint: Look at what Capriracer does for a living and decide if he is offering good information.

I'd note the heat pictures references for a tire at 30 psi is for a tire that is underinflated for the load being applied. The proper air specifications to carry the load have been provided, and at the advised pressures are not underinflated TO CARRY THE SAME LOAD as the OEM-P series tire. Not all situations require taking full advantage of the higher inflation pressures that the LT tires can operate. The proper application and use of load tables is advised here.

 

[Ramblin Fever]

I appreciate all the advise, I believe Capriracer is a tire specialist?

I also have a 3/4 ton truck that I run 10-ply tires on in this same exact size, I would never run less then 60psi in those tires for *that* truck.

For my 1/2 ton Rodeo that weighs in at around 5,500lbs give or take, I don't believe that the 50psi cold pressure on the tire is what is actually needed.

I will run with the psi amounts Capri has mentioned and see how it goes for now....

 

[ARCOgraphite]

Originally Posted By: Ramblin Fever
I appreciate all the advise, I believe Capriracer is a tire
.....
For my 1/2 ton Rodeo that weighs in at around 5,500lbs give or take, I don't believe that the 50psi cold pressure on the tire is what is actually needed.

...
incorrect weight on the Rodeo.
Yor vehicle** weighs 2 tonnes (4000lb) dry and has a gvwr of 5000lbs fully laden - so it WEIGHS LESS THAN A KIA MINIVAN.

**2003 rodeo

 

[Rand]

the only problem I have with the heat sensitive camera thing is the fact that they dont list the ambient temperature.

and the different between gentle green and angry red is aprox 5-7degrees celcius

What would that picture look like if it was 36psi at 70deg F outside? vs 30psi at unknown ambient temp.

also a rodeo is hardly a max load that they put on the tires for the test.

I would have no problem running them at 36psi personally.

 

[Ramblin Fever]

Originally Posted By: ARCOgraphite
Originally Posted By: Ramblin Fever
I appreciate all the advise, I believe Capriracer is a tire
.....
For my 1/2 ton Rodeo that weighs in at around 5,500lbs give or take, I don't believe that the 50psi cold pressure on the tire is what is actually needed.

...
incorrect weight on the Rodeo.
Yor vehicle** weighs 2 tonnes (4000lb) dry and has a gvwr of 5000lbs fully laden - so it WEIGHS LESS THAN A KIA MINIVAN.

**2003 rodeo


Perhaps when it came stock from the factory; I've had this truck weighed in twice, it comes up at 5,470lbs. I have a 97 rodeo, not a 2003....total different trucks.

Doesn't matter...but I didn't see a suggestion from you...did I miss it?