Tow vehicle tire pressure?

[madmaxmutt]

Looking at this sticker, I wonder why they want so much pressure in the rear and less in front where most of the unloaded weight is?14611

It would seem to me, the engine weight would require higher pressure. The empty bed would require lower pressure. I could see raising both while loaded or towing. I am missing some large piece of information here . . .

For that matter, my F150 had the same pressure listed for front and back, which never made any sense to me either.

Thoughts?

[sourdough]

My Ram is 65 front and 80 rear. Just figured the higher rear pressure was to make sure my kidneys were fully jelled....:D

[JRTJH]

The "other part" of the tire pressure placard isn't pasted on the door jamb by Ford. Rather they put the information (somewhat ambiguously) in the Owner's Manual. Essentially, given this example, the "recommended pressure" is for "vehicle operation at max GVW" In the pretense of "dummy down owners" (I don't like that process at all) the old tire load/pressure chart has been removed from the vehicle owner's manuals.

Essentially, as you can see in the picture. The pressure indicates "at max load/max speed".

Used to be, back in the 70's, a chart in every owners manual that listed every tire size and a recommended pressure based on load on that specific axle. I suppose that got to be too complicated to explain in 140 characters, so through the years, all the auto manufacturers just removed the "tire load chart" from the owner's manual and rather than "confuse owners" they just recommend the "single pressure" and leave it to owner's to "unconfused themselves".... Many just "air up to the placard and complain about rough ride".....

Here's an example of what the tire pressure placard "used to say" That yellow square on the side bar pretty much explained that the figures were for "maximum load/GVW".... I'd guess that "confused some people who thought they had to drive 100 MPH (see the picture) and after someone spilled hot coffee in their lap while speeding, the manufacturer "Dummied down" the placard to stay out of court...... <sigh> Yeah, some really are that naïve (I'm trying to be nice)....

[sourdough]

The "other part" of the tire pressure placard isn't pasted on the door jamb by Ford. Rather they put the information (somewhat ambiguously) in the Owner's Manual. Essentially, given this example, the "recommended pressure" is for "vehicle operation at max GVW" In the pretense of "dummy down owners" (I don't like that process at all) the old tire load/pressure chart has been removed from the vehicle owner's manuals.

Essentially, as you can see in the picture. The pressure indicates "at max load/max speed".

Used to be, back in the 70's, a chart in every owners manual that listed every tire size and a recommended pressure based on load on that specific axle. I suppose that got to be too complicated to explain in 140 characters, so through the years, all the auto manufacturers just removed the "tire load chart" from the owner's manual and rather than "confuse owners" they just recommend the "single pressure" and leave it to owner's to "unconfused themselves".... Many just "air up to the placard and complain about rough ride".....

Here's an example of what the tire pressure placard "used to say" That yellow square on the side bar pretty much explained that the figures were for "maximum load/GVW".... I'd guess that "confused some people who thought they had to drive 100 MPH (see the picture) and after someone spilled hot coffee in their lap while speeding, the manufacturer "Dummied down" the placard to stay out of court...... <sigh> Yeah, some really are that naïve (I'm trying to be nice)....


^^^This is right. I run 60-65 psi front and rear when not towing. Run full 80psi in the rear with the trailer. The truck does not need maximum carry ability when empty....

[slow]

If running lower tire pressures and wheels equipped with TPMS, do not go lower than 20% of recommended tire pressure to avoid the warning being displayed on the dash.

Our F250 recommends 65 psi, I run unloaded at 55 psi. One morning the temp dropped and the warning indicator displayed because the psi dropped below 50. Luckily no tool is required to reset the TPMS so an easy fix and no trip to the dealer required.

[jsmith948]

Remember the Ford Explorer/Firestone tire issue a few years back?
Ford recommended a lower tire pressure to enhance the ride of their popular SUV. Many blowouts/rollovers later, they changed their ways. Like most issues, a little common sense can help.
A complicating factor comes in to play for those who have bought into the idea of nitrogen filled tires. How do they lower their tire pressure when empty and then raise their tire pressure when loaded?
BTW - I ALWAYS refill my tires with 78% nitrogen mix - much less expensive and seems to support the wait okay.:rolleyes::hide:

[Hodgy]

BTW - I ALWAYS refill my tires with 78% nitrogen mix - much less expensive and seems to support the wait okay.:rolleyes::hide:


I use the same mix, seems more places carry it rather than the 100% pure !

.

[CWtheMan]

Looking at this sticker, I wonder why they want so much pressure in the rear and less in front where most of the unloaded weight is?14611

It would seem to me, the engine weight would require higher pressure. The empty bed would require lower pressure. I could see raising both while loaded or towing. I am missing some large piece of information here . . .

For that matter, my F150 had the same pressure listed for front and back, which never made any sense to me either.

Thoughts?

A complete explanation is complicated. It requires researching a number of individual sections of the FMVSS and vehicle certification. NHTSA has mandated that the vehicle manufacturer's recommendations are correct. They have also mandated that any exceptions from the recommendations must be described in the vehicle owner's manual.

There is an industry wide standard that says any tire found to be 20% below recommended inflation is (theoretically) in a "run flat" condition and should be inspected for external or internal damage. So, if you're running your rear tires at something below 64 PSI when the placard calls for 80 PSI they are considered "flat". See what I mean by complicated? A savvy owner may know that's not the case for their vehicle because they know what it's carrying all the time. But, then there is the argument about load capacity reserves. Does an owner's settings provide any?

[Desert185]

The more you dumb something down, the dumber people get. Education should be the endeavor, not the dumbed down, government mandated specification.:banghead:

[travelin texans]

If motorhomes are like trailers/5th wheels the manufacturer puts just barely enough tire to handle the loaded rv even at the recommended gross weight & max tire pressure. In my opinion inflate to max pressure indicated on the tire sidewall & if much too stiff deflate 5lbs, adjust a couple pounds +/-, watch tire wear, & be sure not lower to the point of a squishy ride which equals underinflated. It's an rv, it will never ride or handle like your car or even a pickup, so don't make this tire issue so complicated.

[JRTJH]

Back before the "dummy down" was initiated by the governmental agencies and regulations with names that none of us can pronounce (NHTSA and FMVSS are a couple), every truck owner's manual contained a chart similar to the one in this link: https://commercial.bridgestone.com/content/dam/bcs-sites/bridgestone-ex/products/TechnicalInformation/TBR/2016-pdfs/TBR%20Load%20and%20Inflation%20Tables%202015.pdf (LT tires start on page 109)

That "individualized chart" contained all the "standard and optional" tire sizes and load range sizes for tires that fit the truck model series. It was "up to the educated owner" to actually look at the tires on his truck, weigh the axle on his truck and use the chart to determine the appropriate PSI to run the tires on his truck. That was when "drivers could think for themselves"....

Then, along came "dummy down" and the "gubmint" took away our ability to reason by mandating a single PSI rating on a "fits all door placard" for the "recommended tire size" (singular) for the truck. That took away the ability of the owner to "think for themselves" or to "upgrade their truck" using available data and maintain a reasonable sense of reliability that the decisions are appropriate based on the manufacturer's load chart in the owner's manual.

Now, after a few (I think 4) generations of "truck drivers" have lost the ability to reason and think independently and the manufacturers no longer provide the information, unless someone actually goes "outside the box" and researches loading for the tires on his truck, the "art of thinking" seems to be lost. No longer is there a "ready reference, provided by the truck manufacturer" with which an owner can reliably inflate his tires to appropriate pressure based on varying payload.

If you'll download the Bridgestone tire load and inflation tables, you'll see that LT tires are designed to be operated at different pressures depending on the load that they are carrying. It's not "rocket science" but it seems that many (maybe most) of todays light truck owners either have forgotten about doing it the "logical way" or, unfortunately, they were never exposed to "how we used to do it" and the art of tire inflation based on payload has been forgotten.

To me, it seems like the "gubmint" has taken away all our "tire load choices" and provided us with a "one size fits all mandate" causing us to lose our choice, but think that when we check the placard and it's always the correct response, then we're solving the problem........ Pavlov's theory at work on the masses......

[CWtheMan]

Back before the "dummy down" was initiated by the governmental agencies and regulations with names that none of us can pronounce (NHTSA and FMVSS are a couple), every truck owner's manual contained a chart similar to the one in this link: https://commercial.bridgestone.com/content/dam/bcs-sites/bridgestone-ex/products/TechnicalInformation/TBR/2016-pdfs/TBR%20Load%20and%20Inflation%20Tables%202015.pdf (LT tires start on page 109)

Tire inflation charts are a bridge between tire manufacturer and vehicle manufacturer. They are standardized and approved by the Tire and Rim Association for that purpose. It was never intended for individual owners to use such charts when adjusting their tire pressures. The haphazardness of such actions boggles the mind with “whit if” safety concerns.

That "individualized chart" contained all the "standard and optional" tire sizes and load range sizes for tires that fit the truck model series. It was "up to the educated owner" to actually look at the tires on his truck, weigh the axle on his truck and use the chart to determine the appropriate PSI to run the tires on his truck. That was when "drivers could think for themselves".... The FMVSS does not work that way. However, the commercial trucking industry does. But, their regulations (FMCSA) are not applicable with FMVSS.

Then, along came "dummy down" and the "gambit" took away our ability to reason by mandating a single PSI rating on a "fits all door placard" for the "recommended tire size" (singular) for the truck. That took away the ability of the owner to "think for themselves" or to "upgrade their truck" using available data and maintain a reasonable sense of reliability that the decisions are appropriate based on the manufacturer's load chart in the owner's manual. The FMVSS directs the vehicle manufacturer to use tires that are appropriate for each and every fitment. Tire inflation charts are used to determine the appropriate recommended inflation pressures for the necessary load capacities. Thus, the Original Equipment tires are a minimum requirement. It’s important to remember that with automotive vehicles a load capacity reserve is provided. It can be provided with tire inflation pressures or with GAWR axles having more capacity than the vehicle’s GVWR. You will often see owners loading their pick-up truck’s to maximum GAWR. That’s going to severely overload the truck above its maximum load, GVWR.

Now, after a few (I think 4) generations of "truck drivers" have lost the ability to reason and think independently and the manufacturers no longer provide the information, unless someone actually goes "outside the box" and researches loading for the tires on his truck, the "art of thinking" seems to be lost. No longer is there a "ready reference, provided by the truck manufacturer" with which an owner can reliably inflate his tires to appropriate pressure based on varying payload. I’ve never seen “varying payload” used in tire industry standards for pick-up trucks. It’s “normal or maximum load”.

If you'll download the Bridgestone tire load and inflation tables, you'll see that LT tires are designed to be operated at different pressures depending on the load that they are carrying. It's not "rocket science" but it seems that many (maybe most) of today’s light truck owners either have forgotten about doing it the "logical way" or, unfortunately, they were never exposed to "how we used to do it" and the art of tire inflation based on payload has been forgotten. Download the Toyo chart. It will give you the same answers for the same sized and designed tires.

To me, it seems like the "gumming" has taken away all our "tire load choices" and provided us with a "one size fits all mandate" causing us to lose our choice, but think that when we check the placard and it's always the correct response, then we're solving the problem........ Pavlov's theory at work on the masses......

Your vehicle may have an approved list of optional sizes and load capacities to chose from. A tire retailer will have such a list readily available.

For a better understanding of tire rules this reference is provided.
https://one.nhtsa.gov/cars/rules/rulings/UpgradeTire/Final/Index.html

FMVSS Guide.
http://www.ntea.com/NTEA/NTEA/Member_benefits/Technical_resources/FMVSSguide/FederalMotorVehicleSafetyStandardsFMVSSGuide.aspx

CFR 49 Part 567 - Certification.
https://www.gpo.gov/fdsys/granule/CFR-2011-title49-vol6/CFR-2011-title49-vol6-part567

Tire industry standards work pretty much hand and glove with government standards and regulations. Newly purchased tires (2015 and up) may have lot’s of industry standard information in their warranty documents.

Some tire manufacturers will have vary comprehensive documents posted on the WWW. Here’s one of them. A little old but still has all the information that conforms to the major tire rules changes made in 2007. In some of my postings I've mentioned auxiliary tire placards. This document shows one in it's appendix.
http://www.tiresafety.com/images/Tire%20Replacement%20Manual.pdf

The Rubber Manufacturers Association has changed it’s name to USTMA. All of chapter #4 is about RV tires.
https://www.ustires.org/about-us Click on publications tab. Click on manuals. Click on passenger and light truck tires.

[JRTJH]

CW,

Based on your response, it's very clear to me that all those "alphabet soup agencies" and their "can't pronounce the name" regulations have consumed common sense and personal responsibility. Apparenlty, some "wet behind the ear kid" with a degree in "rubber management" can solve the transportation department problems and as long as it's on a sticker, all is golden.

Gone are the days of airing truck tires to accommodate an empty bed, changing the pressure if you have a 1000 pound load or increasing the load to maximum if you're carrying a large cab-over camper. The "soup brand" regulations just say, "increase the PSI to 80 rear and 65 front" regardless of whether there's a 1000 pound payload or a 5500 pound payload.

As I said, the "gubmint done dummied us down so far we can't think for ourselves".... Now, it's check the sticker, add air and check the TPMS, if the bell sounds and the light goes off, salivate and they'll give you a treat. Pavlov would be proud.....

[madmaxmutt]

Thank you all! This is a great discussion. Apparently my stealership bought into both the sticker tire pressure empty and the nitrogen fill (which they wanted $90 for LOL). I told them to keep the refill the tires with air, which they didn't appreciate. I didn't even think about the tire pressure until bouncing down the road, I changed screens and thought; What the?

Even with my trailer and stuff loaded for camping, I am NOWHERE near what this truck is designed to carry. I will probably lower the rears to something softer. Throw caution to the wind and take the chance that kid with water behind his ears doesn't find me:)

[JRTJH]

Unless you have a nitrogen cylinder and regulator in your garage, it's virtually impossible to properly maintain tires on a truck that requires changing the tire pressure from "empty PSI range" to "loaded PSI range". That said, it makes sense that if the manufacturers can "dummy down the general public" they can sell us a nitrogen "green tire package" and keep us coming back for pressure checks. The only problem is that most of us will "lose our kidneys" before we decide to manage the PSI properly for an empty truck.

Given that and the "alarm settings" for most OEM truck TPM Systems, if they are set to alarm at 20% of 80 PSI, then if we set the tire pressure below 64 PSI (80% of 80PSI) then the alarm setting will be reached. Is it any wonder why the placard pressure is 65PSI front and 80PSI rear? Just doing the math, there's one more "dummy down example"....

And yes, Dorothy, the rabbit hole has the same PSI rating for the front axle on the 6.2l gas engine and the 6.7l diesel engine. You can't convince me that it's all about the limitations of the TPMS system settings, not the "best management pressure for tires with a given load on them".....

[sourdough]

Here's the deal IMO. If you grew up using tires, carrying loads and paying attention to tires you KNOW that today's one size fits all "guidelines" are nothing more than political correctness gone amuk....yet again.

I air my tires to fit the situation. My little alarm goes off when I crank up and the little low tire indicator turns on. Do I get worried? Shut things down until I find the problem? Of course not. The little yellow light tells me how stupid those that put those things on there have become. If it came on when it was "low", something that meant something, then I might be concerned. To tell me that the tire is "low" from its max pressure when not towing is just.....silly.

[JRTJH]

There was a time (years ago, back in the 70's and before) when the auto manufacturers provided a chart for us to use to adjust pressure based on what we were using the truck to carry. Then this "stuff started"....

Now, within the past year, we've talked on this forum a number of times about how to use chalk or powder to determine tread contact with the road surface. Why are we doing this? Because we're being "railroaded" into reinventing the wheel every time we need information... I think (just my opinion) that there's charts (used to be available for our use) that are no longer readily available, that would give us the exact pressure to use with a given tire load. But, no, those charts are no longer available to us, we have to rely on chalk or powder to determine what pressure to use so we can maximize tread contact, when that information is "readily available" to the industry. Why? Because we aren't "smart enough to use it or process it properly".... At least that's what I believe.

[Hodgy]

.

Good information, good discussion.

My head hurts ! ! !

.