Tire pressure on TT and TV

[don648]

I came to 45 psi on the rear of my truck through trial and error. My setup handles great at that psi without going over the sidewall max. The setup you have might work fine at what your door sticker calls for, mine was too spongy.

[bono]

A practical question - I have more less 25 minutes from home to the storage place where I park the trailer.

My TV regular tire pressure is 34 psi. The max is 50 psi. When I get to the storage place, the psi is higher - let's assume it is 42 psi (increased by 8 psi). I would like increase the tire pressure to max, i.e. 50 psi (cold).

I tried to add the difference (8 psi) to the final pressure measured in the storage place, but it does not work like that. When the tires got cold, the cold pressure was 45 psi.

Is there any workaround, apart from increasing the pressure before taking off to the storage place?

By the way, I felt the difference between 45 psi and 50 psi - TV was less stable, nothing serious but enough to feel the difference.

[don648]

I always try to set my pressure cold before I drive because after driving there always seems to be one or two psi difference between them.

[Vaquero]

I just got back from the southern Rockies.
Elevation makes a big difference in tire pressures. More so than heat from driving.
From 1200' to 12000' elevation showed 5PSI higher.

No TT this trip. Just food for thought.

[Jagiven]

There is a lot of poor information in this thread.

First for the tt, run max tire pressure, all the time. Check th when cold. When I check them I am usually +/- a half psi.

The TV, is where there alot of miss understand. The TV manufacturer's set the recommended tire pressure on and empty vehicle, for a few reasons. One, they need a good EPA rating, and out of the factory is what counts for their records. Two, many people do not haul or tow, so they want a good ride off the showroom floor. Now if you tow or haul, your requirements have changed from an empty TV, and the factory does not know what you are going to do.

You can and should adjust your tire pressure based on your driving requirements. There are load charts to help determine what might be a good tire pressure for your load. From there be willing to try a verify of different pressures. Your front and rear presss do not need to be the same.

For example I replaced my OEM tires with a different brand that match all specifications exactly of the OEM. You would think, they would ride the same. They do not. During the summer I run 10 extra psi in the rear and 5 extra in the front. Because I do not put a lot of miles on my TV without the trailer, I keep this ratio all summer, in the winter I drop it.

[CaptRon53]

Where are the mythical tire pressure load charts? I have not seen any....

[Rustysocket]

Originally Posted by CaptRon53

Where are the mythical tire pressure load charts? I have not seen any....

https://toyotires-1524598101.netdna-...s_20151020.pdf

[kevcarr59]

I'm going to have to add .02 here on this thread. First of all, you ALWAYS check & adjust air pressure with the tires COLD. Manufacturers stickers are for the stock tires that came with your vehicle, they don't take into account your aftermarket choices.

If I ran our original P metric tires, with our '16 264BHW at about 5800-6000 GVW, at the air pressure it said on the door decal, we'd be dead. With the TV tires aired at max pressure, along with the TT, the truck ride was "squishy", to say the least. This was on a trip from Austin to Galveston. When we got back, a quick trip to Discount Tire for new TV tires took care of that. This next long trip I plan on upping the TV air pressure to 65#, and see how that works. After dropping the trailer I put the TV tire pressure back down to 35#, and the truck rides fine.

Our TT had less than 750 miles on it, and I really don't think I should have had a blowout already. It was July, it was hot, the tires were at 50 psi., and it was curbside rear axle, so I doubt I ran over something. I don't know how a manufacturer can put a 4 ply, 50 mph speed rated tire on a trailer that has a 6500# GVWR.

Would I be able to keep the original tires on the trailer, maybe?? Do you want to be following me when it blows out, I highly doubt it! I'm just disgusted overall. I've had to replace tires on the new truck, replace warped wheels on the old truck, and now new trailer tires. This is about $1700 I didn't plan on spending.

I've driven many kinds of truck for the previous 25 years, flatbed, tanker, container chassis, among others. I ALWAYS checked the tires before leaving for any trip.

[homer1959]

Originally Posted by Jagiven

There is a lot of poor information in this thread.


The TV manufacturer's set the recommended tire pressure on and empty vehicle, for a few reasons. One, they need a good EPA rating, and out of the factory is what counts for their records. Two, many people do not haul or tow, so they want a good ride off the showroom floor. Now if you tow or haul, your requirements have changed from an empty TV, and the factory does not know what you are going to do.

Wow where did you get that ???

Poor information in this thread ? I wonder from where its coming from

I would like to beleive you but I need more than asumption or opinion.

the factory doenst know what we are going to do but the factory know pretty well that if you use the vehicle unloaded and or loaded to the maximum of passenger and cargo, at what you should set your tires pressure

The charts posted here isnt designed to allow peoples to play with the pressure of the original tires that were installed on a vehicle, or tires of the same construction size and rating , here is what they say :

This guide is intended to provide assistance in utilizing
load and inflation tables
when replacing tires
with optional tire
sizes including “
plus sizes


The recommended pressure is determine for the whole scale of operation of the truck.

Its pretty clear :

WARNING! The maximum inflation pressure indicated on the sidewall of the tire may
NOT
be
the recommended cold inflation pressure for your vehicle. Refer to your tire information placard
or owner’s manual for the proper cold inflation pressure and the recommended tire size. The tire
information placard (T.I.P.) can be found on the vehicle
door edge, door jam, glove

So there is no descimination on the official document ( placard ) between empty or full, nor any warning in this case that you need a different pressure when loaded

On page 7 of the chart we can see the placard usually placed on driver door jamb,.... they show combined weight of the occupants and cargo and right below the pressure determined by the vehicle manufacturer.

This placard is for the tires coming on the vehicle, or a tire of the same rating and construction and size.

On the very same page they state that you need to apply a sticker near the placard of the vehicle if a new pressure is determined by a change of tires:

If the replacement tire requires a different inflation pressure than OE, the installer should
inform the owner of the new required inflation pressure and should also place a sticker or
decal over the vehicle tire
placard showing the new tire size and recommended inflation

Anything else is opinion, misconception, or poor tire quality selected for the application, and at the end placebo effect.

Life can be simple or complicated. One can play engineer for his own good, but steering peoples from a valid or officials documents is a chance that one should not take.

Finally I am willing to learn, from official sources, and when you say :

There is a lot of poor information in this thread

I would like to know where you are taking yours and if your source contradict the official sources easily found on the internet and or on your vehicle Ill be the first one to pursue the research on tire pressure determination.

[BuddyRay]

Two things that came out of this Thread":

Just because someone works at a Tire store, it doesn't make them an expert on tires, tire pressure, towing, or your particular situation.

Sadly, this is true in WAY too many situations / industries / stores today. And in the RV industry we hear it again and again. "The salesman at my dealer told me that hooking the propane line to the water input was the best way to winterize the trailer!"

The guy/gal at the tire store that confidently tells you what tires you should buy - or how you should use them - was probably working at BestBuy a week ago - and didn't know anything about electronics either. Yet we humans WANT to "believe" when we're talking with someone who has a name tag that says "Ask Me! I'm the expert!"

The other thing that is obvious from this thread is that this is NOT a SIMPLE subject. There are a huge number of variables, factors and issues. But it is important for a vehicle owner to educate themselves on tires.

Who to believe if not salespersons? Well, I don't put nearly as much faith in "engineers" as others in this thread. It's not that I don't think they know of what they speak. It's that, having worked with and around engineers my whole career, I can't count the number of times I've heard management say:
"Yes, I know that's what the engineering says but if we want to sell this we have to . . . "
"Yes, I know that's what the engineering says but to make a profit we have to . . . ."
"Yes, I know that's what the engineering says but to get this past the FCC we have to . . . . "
"Yes, I know that's what the engineering says but our Lawyers say . . ."

So my personal, informed decision after reading this and other treads, is to consider the door sticker as a "Recommendation" (which is the wording my door sticker uses) that produces the best ride and best gas economy in the truck as it came from the factory. I'll take the Max. Pressure on the side of the tire as just that - a maximum that tire may safely be inflated to. And I'll run my tires somewhere between the door sticker and the max pressure where it makes a combination of sidewall and ride best when I'm towing. And I'll keep a close watch on my TPM system and tire temperature.

YMMV

[homer1959]

Originally Posted by BuddyRay

Two things that came out of this Thread":

Just because someone works at a Tire store, it doesn't make them an expert on tires, tire pressure, towing, or your particular situation.

Sadly, this is true in WAY too many situations / industries / stores today. And in the RV industry we hear it again and again. "The salesman at my dealer told me that hooking the propane line to the water input was the best way to winterize the trailer!"

The guy/gal at the tire store that confidently tells you what tires you should buy - or how you should use them - was probably working at BestBuy a week ago - and didn't know anything about electronics either. Yet we humans WANT to "believe" when we're talking with someone who has a name tag that says "Ask Me! I'm the expert!"

The other thing that is obvious from this thread is that this is NOT a SIMPLE subject. There are a huge number of variables, factors and issues. But it is important for a vehicle owner to educate themselves on tires.

Who to believe if not salespersons? Well, I don't put nearly as much faith in "engineers" as others in this thread. It's not that I don't think they know of what they speak. It's that, having worked with and around engineers my whole career, I can't count the number of times I've heard management say:
"Yes, I know that's what the engineering says but if we want to sell this we have to . . . "
"Yes, I know that's what the engineering says but to make a profit we have to . . . ."
"Yes, I know that's what the engineering says but to get this past the FCC we have to . . . . "
"Yes, I know that's what the engineering says but our Lawyers say . . ."

So my personal, informed decision after reading this and other treads, is to consider the door sticker as a "Recommendation" (which is the wording my door sticker uses) that produces the best ride and best gas economy in the truck as it came from the factory. I'll take the Max. Pressure on the side of the tire as just that - a maximum that tire may safely be inflated to. And I'll run my tires somewhere between the door sticker and the max pressure where it makes a combination of sidewall and ride best when I'm towing. And I'll keep a close watch on my TPM system and tire temperature.

YMMV

LOL I hear you about engineer LOL ....they are a strange species, but they are a necessity .....

Your approach to tire pressure is a good one, for you, because its for your taste, application and seat of the pants feeling, its good for you, not neccessarely good for someone else or for the tires and or vehicle

At the end we are all free to do what we want , but the authority isnt me nor the teenagers at pep boys...we have to rely on one official source only after that one is free to inflate or deflate his tires to HIS preference and taking the good and the bad coming from this action.....

[DocBrown]

Here's what my manual says about proper inflation:
The recommended cold tire inflation pressure, shown on the label, is the minimum amount of air pressure needed to support your vehicle’s maximum load carrying capacity.

No where does my manual say that you should not inflate the tires beyond what the door sticker says. The above statement infers that you can certainly increase the PSI to better support the load. And personal experience in 20+ years of towing says yes, the towing experience is dramatically improved by increasing the PSI on my rear tires.

That said I run my rear tires at 48 PSI when towing.

When not towing I run the tires at the pressure recommend on the door sticker.

[homer1959]

Originally Posted by DocBrown

Here's what my manual says about proper inflation:
The recommended cold tire inflation pressure, shown on the label, is the minimum amount of air pressure needed to support your vehicle’s maximum load carrying capacity.

No where does my manual say that you should not inflate the tires beyond what the door sticker says. The above statement infers that you can certainly increase the PSI to better support the load. And personal experience in 20+ years of towing says yes, the towing experience is dramatically improved by increasing the PSI on my rear tires.

That said I run my rear tires at 48 PSI when towing.

When not towing I run the tires at the pressure recommend on the door sticker.

I agree with you nowhere they say that you cannot.....nor that you have to.

Yes its a recommendation I would say based on scientific evidence, not on the flavor of the month.

For the best overall performance and durability its the pressure on the placard.

Higher pressure might help a P rated tire, but IMHO a truck should not come with car tires, I would guess that many of the squirrily truck behavior report comes from this type of tires.

Now how much to add for as you say.... a better support... for the weight added to the truck ? A bit ? a bit more ? Much more ?

How much is too much ? At what point are we going to ride on a skateboard ? At what point are we going to wear out the center of the tread prematurely ? Since the tire ride at higher pressure at what pressure are we going to add additional stress to the suspension ?

Its to the driver to decide for his application and its approximate and subjective, with no scientific base.

The placard is the one fits all solution, a safe one , done by professional any other suggestion is an opinion...

Im not saying that the peoples increasing the pressure are doing something wrong, Im just saying that its wrong to become a Monday morning engineer and promoting our own truth.

Doc Brown do not take me wrong I' m not saying that is what your doing , im talking in general , and I always like a good debate :-)


Thanks God we live in a free world

[Atlee]

My current truck came with OEM 17" LRE tires. The yellow door placard recommends 55# front and 60# rear, and that what I keep them at. However, I pull a relatively light weight TT which has a GVWR of 4950#. Should I get a new trailer that adds a couple of grand in weight, I will revisit the TV tire pressure. I may leave it as it is, or I may add some air, especially in the rear.

All of that said, my previous truck, which had OEM 16# P tires, pulled the same trailer I have now 7900+ miles cross country in 2014. I did air the P's up to their max pressure, 44# if I remember correctly. I can say the truck handled the trailer extremely well. Coupled with my Equal-i-zer hitch, the entire combo, TV and TT, behaved in a most civilized way.