Increase tire pressure when towing?

[JExpedition07]

I tow my dual axle enclosed trailer a decent amount and don’t air up, no issues here.

Sponsored

 

[Davexxxx]

Word of caution here the factory P-series tires (and all SL P-series tires) are rated to carry their maximum load at 35psi. Adding more pressure doesn't increase load carrying capacity as it would on an LT Tire.

https://www.tirerack.com/upgrade-garage/what-is-maximum-load-for-a-tire

That seems interesting and I even kinda like the idea of that much standardization in the ratings, of a crucial, function and safety involved product but we've all seen the stamps on the tires of "Max Load of x,xxx @ xx PSI" and have that PSI be different than the door sticker and or 35 PSI.

The article infers that, that is max pressure, not max load but thats not what the stamps on the tires say.

Can you explain the discrepancy?

 

[UGADawg96]

Here is a good load index and inflation table reference guide:

https://www.toyotires.com/media/2125/application_of_load_inflation_tables_20170203.pdf

 

[{tpc}]

I air mine up when towing, always have. But usually not above 44. I run 38-40 psi give or take when not towing.

 

[ks54703]

https://www.google.com/search?clien...+will+blow+first+under+or+fully+inflated+tire

All that is needed to be said.

 

[24Carbon150]

I’m not sure in what world a mechanic tells a customer to put 14 psi more than a tire is capable of handling in said tire is a good idea. If you are towing heavy , close to the upper spectrum of your towing capability with P rated tires I would highly suggest you run them at max, anything over bout 6,000 lbs 35psi would be too low in my opinion, youll get tons of squirm out of those rear tires.

 

[UGADawg96]

Do we know which exact tires the OP has ?

https://www.f150gen14.com/forum/threads/basic-tire-questions.19765/#post-383002

 

[Aonarch]

Word of caution here the factory P-series tires (and all SL P-series tires) are rated to carry their maximum load at 35psi. Adding more pressure doesn't increase load carrying capacity as it would on an LT Tire.

https://www.tirerack.com/upgrade-garage/what-is-maximum-load-for-a-tire

Thanks for sharing this!

Even though I have load range C tires, based on this it looks like I'd need to go up to 50 psi for max load. I thought it would be the opposite of a SL/XL.

 

[Chris GTO TT]

That seems interesting and I even kinda like the idea of that much standardization in the ratings, of a crucial, function and safety involved product but we've all seen the stamps on the tires of "Max Load of x,xxx @ xx PSI" and have that PSI be different than the door sticker and or 35 PSI.

The article infers that, that is max pressure, not max load but thats not what the stamps on the tires say.

Can you explain the discrepancy?

If your truck originally came with P-series tires the door sticker will be based on that. If you or a previous owner put on LT tires you'll need to use a conversion to ensure you have enough pressure to carry the loads you want to carry.

 

[Davexxxx]

If your truck originally came with P-series tires the door sticker will be based on that. If you or a previous owner put on LT tires you'll need to use a conversion to ensure you have enough pressure to carry the loads you want to carry.

I have OEM tires but you didn't answer my question.

 

[Chris GTO TT]

I have OEM tires but you didn't answer my question.

P-series tires have a stated maximum load and a separate maximum pressure. SL tires carry their rated maximum load at 35psi, anything beyond 35psi just helps to stiffen the sidewall.

LT tires are rated differently, they are the ones that state x,xxx lbs @ xx psi. On those tires the more pressure you add the more weight the tire can carry until you reach max pressure and load.

There isn't a discrepancy there are 2 different rating systems depending on if your tire size starts with P or LT.

 

[amschind]

I like your science book. Please send to me.

Sure, the working title is "$&@# You Learn From Being Wrong". It's free in dollars up front, but pretty expensive in terms of time and "dollars after the fact". I'm still working on the "nuclear physics" section, since I'm pretty dependent upon Russia and Ukraine to provide the needed examples ever since the cowboys at Los Alamos and Arco, Idaho got replaced by OSHA compliant scientists. The first subsection in that chapter is called "Why You Shouldn't Hold Neutron Reflecting Beryllium Hemispheres Surrounding a Hunk of Plutonium Apart With a Screwdriver".

More Ways To Be Brave Than Carrying A Rifle

 

[Davexxxx]

P-series tires have a stated maximum load and a separate maximum pressure. SL tires carry their rated maximum load at 35psi, anything beyond 35psi just helps to stiffen the sidewall.

LT tires are rated differently, they are the ones that state x,xxx lbs @ xx psi. On those tires the more pressure you add the more weight the tire can carry until you reach max pressure and load.

There isn't a discrepancy there are 2 different rating systems depending on if your tire size starts with P or LT.

I'm always happy to learn something, even if I might be a tough sell, thanks.

My tires do not have the @. They are separate lines, just as you described.

 

[Buyer2021]

I'm always happy to learn something, even if I might be a tough sell, thanks.

My tires do not have the @. They are separate lines, just as you described.

Same here, I stand corrected.

There isn't a discrepancy there are 2 different rating systems depending on if your tire size starts with P or LT.

Just FYI our OE 275/65R18 Goodyear Wrangler Territory ATs have neither a "P' nor an "LT" prefix, indicating that they are subject to the (yet another) ISO Metric (E.T.R.T.O.) rating system?

Granted, for purposes of this discussion that seems to be essentially comparable to the "P" system insofar as pressure matters.

 

[Chris GTO TT]

I'm always happy to learn something, even if I might be a tough sell, thanks.

My tires do not have the @. They are separate lines, just as you described.

One thing I do want to make clearer because in reading my last response I realize it could be misunderstood. A SL P-series tire does carry more load with more pressure until you reach 35psi where reaches its maximum load.

It took me a while to fully grasp this concept myself, but I'm also weird I love researching tires and information about them.

Sponsored