Firestone tire pressure

goducks10 wrote:

Grit dog wrote:

nano wrote:
I just want to make sure I don't set them too low.

The ole biscuits numbers are about right. I run the same +\- but will go lower in the winter if running ice and snow all the time unloaded. Your dealer is full of shiiiiii....., BUT with TPMS and a 2500 you will get the tire light if you lower the tires below the preset threshold. It's around 65F/75R psi based on the 2014 models I've had. Yours may still have the light load feature to temporarily lower the threshold. But even that is too high for empty driving iirc.
2 options, lower pressure and live with the idiot light or find a dealer or shop with witech software and change the TPMS thresholds.
You will not hurt anything running with the light on, nor will you hurt anything down to about 40/30 psi for normal unloaded driving. Noting optimum pressure is a bit higher.

2012 Rams do have the light load button. I have no issues running at 45 psi on the rear and setting the light load. Only issue I have is when I get up around 55 psi. It seems like the TPMS can't figure out if it's light or heavy.

That's cool. Wasn't sure if they kept the light load feature all the way to the new chassis. It's bs to have the thresholds that high and hard to find a dealer to re program.
Nice feature about current 3500s, exempt from the more restrictive TPMS so one can adjust pressure as necessary.

Weigh your trucks front and rear axles. Look up weight/inflation chart add 5psi to rear and 10 psi to front above what the chart says.

nano wrote:
We have a 2012 Ram 2500 diesel SLT 4x4. We have the stock Firestone tires on it. Transforce (?) if I'm remembering correctly. LT265/70R17. What should the front and rear be at when not towing or hauling anything? They are currently wearing at the center, but the Dodge dealer said they are set at the correct pressure. I online chatted with someone at Firestone, and they gave me the same pressures as the dealer. When I explained the wear, they told me to call a local Firestone tire dealer. *sigh* I thought they had an inflation chart, but can't find it.

I am able to calculate it for you , but need some data for it.
Hardest part of this is to determine the weight on seperate wheels/tires, this is often estimated and misyudged.
So here lies the danger in calculating, the calcululation I use is super-save, probably give a bit to high pressure , but if you determine to low loads on tire, the outcome is also to low pressure.

And someone wrote it already here, You never want to low pressure because it leads to tire failure and blowing tires and accidents, with all the missery that can go with it.
To high pressure gives centre wear and discomfort, but never dangerous situations. OK some more chance on punctures, and loss of gripp mayby.

Luckily there is a large range pressure in wich the tire dont get to hot , and comfort and gripp is still acceptable.

so if loads are determined as accurate as possible, and speed for the situation also, and my determined reserves included , you probably have some reserve for things like:
Pressure loss in time.
Incidental extra loading.
misyudging of weights.
Inacurate reading of pressure scale.
etc.
etc.

From tires I need :
maximum load or loadindex
AT-pressure or Loadrange ( D-load LRD= AT-press 65 psi,LRE AT 80 psi,LRC=AT50psi).
max speed or speedcode ( Q is up to 160km/99m/h N=up to 140km/86m/h)

Try to find this all and I will calculate a as save possible pressure at wich comfort and gripp are still acceptable.

Grit dog wrote:

nano wrote:
I just want to make sure I don't set them too low.

The ole biscuits numbers are about right. I run the same +\- but will go lower in the winter if running ice and snow all the time unloaded. Your dealer is full of shiiiiii....., BUT with TPMS and a 2500 you will get the tire light if you lower the tires below the preset threshold. It's around 65F/75R psi based on the 2014 models I've had. Yours may still have the light load feature to temporarily lower the threshold. But even that is too high for empty driving iirc.
2 options, lower pressure and live with the idiot light or find a dealer or shop with witech software and change the TPMS thresholds.
You will not hurt anything running with the light on, nor will you hurt anything down to about 40/30 psi for normal unloaded driving. Noting optimum pressure is a bit higher.

2012 Rams do have the light load button. I have no issues running at 45 psi on the rear and setting the light load. Only issue I have is when I get up around 55 psi. It seems like the TPMS can't figure out if it's light or heavy.

Thanks for the responses! I will be lowering pressures.

rhagfo wrote:

Grit dog wrote:

nano wrote:
I just want to make sure I don't set them too low.

The ole biscuits numbers are about right. I run the same +\- but will go lower in the winter if running ice and snow all the time unloaded. Your dealer is full of shiiiiii....., BUT with TPMS and a 2500 you will get the tire light if you lower the tires below the preset threshold. It's around 65F/75R psi based on the 2014 models I've had. Yours may still have the light load feature to temporarily lower the threshold. But even that is too high for empty driving iirc.
2 options, lower pressure and live with the idiot light or find a dealer or shop with witech software and change the TPMS thresholds.
You will not hurt anything running with the light on, nor will you hurt anything down to about 40/30 psi for normal unloaded driving. Noting optimum pressure is a bit higher.

X3 Old Biscuits thoughts, not only better wear, but far better traction in rain and snow.

I also don't run 80 psi in the rear loaded as I would have 6,830# of capacity, and only carrying about 5,500# of weight on the rear axle, between 65 and 70 psi.

My 17" tires are rated at 3195#/80psi. I run 80psi cause I am towing heavy...right at rear tire max load rating

nano wrote:
I just want to make sure I don't set them too low.

You will want to set them too low for a while to even out the wear, though. A little too low for a while will not be catastrophic, especially if you're not hauling a load.

Frankly any tire inflation chart will do as long as the tire has the same size and load rating. I've seen a couple different charts from different manufacturers and they were pound-for-pound identical on the same size, same load range, tires.

Dealers & mfg's go with max to protect themselves, sighting that "we don't inflate properly under load and most failures are from under inflation."

So lower them when empty and raise them under load.

Just dropped the rear on mine to 45 about 3 weeks ago. Much better ride and better traction.

Grit dog wrote:

nano wrote:
I just want to make sure I don't set them too low.

The ole biscuits numbers are about right. I run the same +\- but will go lower in the winter if running ice and snow all the time unloaded. Your dealer is full of shiiiiii....., BUT with TPMS and a 2500 you will get the tire light if you lower the tires below the preset threshold. It's around 65F/75R psi based on the 2014 models I've had. Yours may still have the light load feature to temporarily lower the threshold. But even that is too high for empty driving iirc.
2 options, lower pressure and live with the idiot light or find a dealer or shop with witech software and change the TPMS thresholds.
You will not hurt anything running with the light on, nor will you hurt anything down to about 40/30 psi for normal unloaded driving. Noting optimum pressure is a bit higher.

X3 Old Biscuits thoughts, not only better wear, but far better traction in rain and snow.

I also don't run 80 psi in the rear loaded as I would have 6,830# of capacity, and only carrying about 5,500# of weight on the rear axle, between 65 and 70 psi.