Tire pressure?

[Pathman]

No! Didn’t mean it like that! ��*♂️

[Hugo-H]

I would never recommend to apply the max tire pressure as mentioned on the tyre... I use a rule for tyre pressure 1 bar / ton weight TT. My TT is max 3.6 ton, so my tyres are at 3.5 bar each...

[travelin texans]

Originally Posted by Hugo-H

I would never recommend to apply the max tire pressure as mentioned on the tyre... I use a rule for tyre pressure 1 bar / ton weight TT. My TT is max 3.6 ton, so my tyres are at 3.5 bar each...

Doesn't help much as in this country we use PSI not bars unless you want a drink.
I guess I could look up bars vs PSI........not!

[Tireman9]

Originally Posted by travelin texans

This topic ALWAYS gets WAY over complicated!
Use the pressures on the placard of your vehicle & quit overthinking it! If the tire looks low when you hook up the rv add air!
DONE!

Yes. I have no idea why so many people think that the pressure on someone else's RV and tires is correct for their RV tires.
Would you try and use the same oil filter the person parked next to you in the campground used on their TV if you had different brand truck or different engine?


Our cars, trucks and RVs all come with a unique and specific "Certification" stickers on them that identify the GAWR (note I said Gross AXLE weight) and the OE tire size and Load Range tire and the inflation needed to support the GAWR (not the GVWR which is a different number and is not always the total of the GAWR.

I have covered the steps on proper inflation more than a dozen times on my RV Tire Safety blog. You can get more detailed answers than you need if you bother to read the blog. Unless you think the guy drinking beer on the next campsite know more about tires than I do as an actual Tire Design Engineer and court recognized Expert on RV tire failures.

[rlh1957]

I have always checked tires first thing before beginning a trip.
I confirm or adjust to max pressure on tire.

Tires will always register higher pressures when you start driving. Not to be alarmed, this is normal.
With our TPMS the pressure and temps go up while driving. We can even tell which side the hot sun is on!

[lcarver02]

Make sure you have the right tires for your Trailer installed. Easy to check specs on-line. Set the tire pressure cold to the maximum rating stated ON THE TIRE. Good advice to always run at maximum pressure. Good wear, less heat, better feel, and your tires will last longer.

Same thing with your truck. Some tires can have recommended minimum tire pressures, but this is pretty much non-existing due to the liability. Always use a good digital gauge to check. Make sure it works right.

If your truck is empty and unloaded you can reduce the pressure some (this is for ride quality, the reduction should not be much). I always run at maximum pressure stated on the tires when towing. Load Range E - 80 psi.

[lcarver02]

Some good advice. I worked for Ford Motor for 25 years, personally experienced this with several fleets that reduced their tire pressures to 45 - 55 PSI on a tire that should have a max of 80 PSI. Why? Because the operators did not like the harsh ride. The shimmy can get so severe it will crack the frame, no exaggeration here. From experience, never go below 65 empty and always go to max tire of 80 psi loaded.

[Pathman]

Originally Posted by Tireman9

Yes. I have no idea why so many people think that the pressure on someone else's RV and tires is correct for their RV tires.
Would you try and use the same oil filter the person parked next to you in the campground used on their TV if you had different brand truck or different engine?


Our cars, trucks and RVs all come with a unique and specific "Certification" stickers on them that identify the GAWR (note I said Gross AXLE weight) and the OE tire size and Load Range tire and the inflation needed to support the GAWR (not the GVWR which is a different number and is not always the total of the GAWR.

I have covered the steps on proper inflation more than a dozen times on my RV Tire Safety blog. You can get more detailed answers than you need if you bother to read the blog. Unless you think the guy drinking beer on the next campsite know more about tires than I do as an actual Tire Design Engineer and court recognized Expert on RV tire failures.

Well then, as a certified tire expert, can you please provide me (as the OP) a simple process for airing up/down my LRE truck tires with a max psi of 80#?

The advice and recommendations from many folks on here has been widely variable, so how is one to know who’s advice to adhere to?

In case you didn’t read all the posts from the start, my original question asked if it’s recommended to “air up” your tow vehicle tires when under load?

Before your post, my mind was set to simply follow the manufacturers placard and owners manual, which states 65PSI for all conditions towing or not.
But now you’ve thrown a wrench into that!LOL

What’s your advice given my question?

Thanks!

[wiredgeorge]

Originally Posted by Pathman

Well then, as a certified tire expert, can you please provide me (as the OP) a simple process for airing up/down my LRE truck tires with a max psi of 80#?

The advice and recommendations from many folks on here has been widely variable, so how is one to know who’s advice to adhere to?

In case you didn’t read all the posts from the start, my original question asked if it’s recommended to “air up” your tow vehicle tires when under load?

Before your post, my mind was set to simply follow the manufacturers placard and owners manual, which states 65PSI for all conditions towing or not.
But now you’ve thrown a wrench into that!LOL

What’s your advice given my question?

Thanks!

Just a thought. Since you have heard a bunch of different opinions, perhaps one is right and all the rest wrong. A discerning individual could probably pick out the correct opinion from all the others. Putting "tire" in a thread chums the water and the Tire Sharks appear. Stick to the tire placard inflation values in your truck's door frame or pick the answer you want. These tire threads seem to be endless and you will see, if you do a search, that no clear consensus ever emerges but everyone with tires is a tire expert. Not knocking the few industry or ex industry folks but as the old saying goes, "opinions are like..." well, you get the idea.

Personally I have jacked up my LRE tires to 80 psi while towing and my truck rode harsh and I don't have a real heavy camper. Might just try using the values on my tire/payload placard!

[Pathman]

Originally Posted by wiredgeorge

Just a thought. Since you have heard a bunch of different opinions, perhaps one is right and all the rest wrong. A discerning individual could probably pick out the correct opinion from all the others. Putting "tire" in a thread chums the water and the Tire Sharks appear. Stick to the tire placard inflation values in your truck's door frame or pick the answer you want. These tire threads seem to be endless and you will see, if you do a search, that no clear consensus ever emerges but everyone with tires is a tire expert. Not knocking the few industry or ex industry folks but as the old saying goes, "opinions are like..." well, you get the idea.

Personally I have jacked up my LRE tires to 80 psi while towing and my truck rode harsh and I don't have a real heavy camper. Might just try using the values on my tire/payload placard!

That’s kinda where I was at before the last poster gave his advice as an expert tire man.

Just to be clear though, I’m not “looking for” a particular answer that I agree with, I’m looking for the best answer that will give me the Safest and best ride possible.
I didn’t think it would be so subjective, which in my opinion it shouldn’t be, but I see what you’re saying.

Thanks!

[rhagfo]

Originally Posted by travelin texans

Doesn't help much as in this country we use PSI not bars unless you want a drink.
I guess I could look up bars vs PSI........not!

Well be high and mighty, but we are the only developed country that still uses imperial measure!

I don't have much use for my SAE tools anymore as almost all fasteners on our Ram are metric, I think you find that true for all of the big three.

John Deere equipment is all metric, as is likely most farm equipment.

[wiredgeorge]

Originally Posted by rhagfo

Well be high and mighty, but we are the only developed country that still uses imperial measure!

I don't have much use for my SAE tools anymore as almost all fasteners on our Ram are metric, I think you find that true for all of the big three.

John Deere equipment is all metric, as is likely most farm equipment.

All my tools are metric and I found out that the big nut you turn to manually drag your slide in is SAE but a 25mm will work. I think a 2002 Cougar is going to be almost exclusively SAE.

[CWtheMan]

Originally Posted by Pathman

Well then, as a certified tire expert, can you please provide me (as the OP) a simple process for airing up/down my LRE truck tires with a max psi of 80#?

The advice and recommendations from many folks on here has been widely variable, so how is one to know who’s advice to adhere to?

In case you didn’t read all the posts from the start, my original question asked if it’s recommended to “air up” your tow vehicle tires when under load?

Before your post, my mind was set to simply follow the manufacturers placard and owners manual, which states 65PSI for all conditions towing or not.
But now you’ve thrown a wrench into that!LOL

What’s your advice given my question?

Thanks!

There are a lot of different answers because there are a lot of "back yard" mechanics giving the answers.

Personally, I post from industry approved regulations and standards, or individual vehicle manufacturers that mimic the regulations/standards in their PDF files/brochures.

Most of the information about tire servicing and maintenance found in vehicle owner's manuals are mandated to be there by NHTSA.

NHTSA publishes a document called SAFECAR. It also has a section for tire servicing but mostly automotive vehicles. RV trailer tires are a little different because they are not required to provide any reserves. That is rapidly changing because of a RVIA recommendation. That recommendation is not binding on vehicle manufacture. However, they are doing it.

Your tow vehicles have a percentage of load capacity reserves built in as mandated by regulations. Because of that, the vehicle manufacturers inflation pressures do not have to be adjusted for OE tires. Thats because of the built-in load capacity reserves. Only overloading the vehicle would/will invalidate the recommended inflation pressures.

The USTMA is the place to look for tire industry standards. I'm adding the link below. Chapter four is dedicated to RVs, all of them.

https://www.ustires.org/sites/defaul...uckTires_0.pdf

[Pathman]

Thanks CW.

[bsmith0404]

Here’s something else for you to read through. This shows inflation psi required for different size and load range tires to carry a specific amount of weight. This goes back to why my original answer to your question (back in like post 4 or something) was that I use different pressures depending on what I’m towing. It isn’t just what is on the sticker or on the sidewall. I probably make it a lot more difficult than I need to and change my pressures a lot more often than I have to. I used to transport for a living, when you go through 2-3 sets of tires per year, they become a major expense. I wanted to make sure I got the most out of each set of tires and I learned how to do that. This chart shows required pressure vs load. You would have to know how much your truck weighs empty and loaded if you wanted to adjust pressures based on this. You can see that there is no such thing as one pressure for all circumstances, but your owners manual says that because they aren’t going to go to the depths required to make the average consumer understand what the pressures should be in different situations. People want it to be simple so they keep it simple.

You may or may not find your exact tire size on this chart, but there are many charts like this put out by just about every tire manufacturer. You can find them if you look.


https://www.yournexttire.com/trailer...flation-chart/

[CWtheMan]

Originally Posted by bsmith0404

Here’s something else for you to read through. This shows inflation psi required for different size and load range tires to carry a specific amount of weight. This goes back to why my original answer to your question (back in like post 4 or something) was that I use different pressures depending on what I’m towing. It isn’t just what is on the sticker or on the sidewall. I probably make it a lot more difficult than I need to and change my pressures a lot more often than I have to. I used to transport for a living, when you go through 2-3 sets of tires per year, they become a major expense. I wanted to make sure I got the most out of each set of tires and I learned how to do that. This chart shows required pressure vs load. You would have to know how much your truck weighs empty and loaded if you wanted to adjust pressures based on this. You can see that there is no such thing as one pressure for all circumstances, but your owners manual says that because they aren’t going to go to the depths required to make the average consumer understand what the pressures should be in different situations. People want it to be simple so they keep it simple.

You may or may not find your exact tire size on this chart, but there are many charts like this put out by just about every tire manufacturer. You can find them if you look.


https://www.yournexttire.com/trailer...flation-chart/

The FMCSA regulations are not applicable for vehicles built under the guidance of FMVSS.

Truckers are required to weigh their loads before hitting the highways. They are only required to inflate their tires to the load carried. The results can be seen on every major highway in the country.

Those inflation pressures in your chart are standardized by the TRA. They are not recommendations. They are a sort of tool used by tire installers when setting recommended inflation pressures for OE tires and "plus sized" tires.

Load capacity reserves are a mandatory requirement for automotive vehicle manufacturers in accordance with FMVSS.

The only way accurate loads across an axle can be determined is by weighing each wheel position every time the load has changed. Maybe you have a way to do that every time you hit the road with your RV but I doubt the percentage of RV travelers that never do it is very high.

"The FMCSA specifies that trucks (and other vehicles, for that matter) cannot operate with tires inflated to under the pressure specified for the load they are carrying. An inspector will measure for cold inflation, and if the truck has been running, they’ll use a formula to correct for any increase in the pressure from heat. "

[bsmith0404]

Originally Posted by CWtheMan

The FMCSA regulations are not applicable for vehicles built under the guidance of FMVSS.

Truckers are required to weigh their loads before hitting the highways. They are only required to inflate their tires to the load carried. The results can be seen on every major highway in the country.

Those inflation pressures in your chart are standardized by the TRA. They are not recommendations. They are a sort of tool used by tire installers when setting recommended inflation pressures for OE tires and "plus sized" tires.

Load capacity reserves are a mandatory requirement for automotive vehicle manufacturers in accordance with FMVSS.

The only way accurate loads across an axle can be determined is by weighing each wheel position every time the load has changed. Maybe you have a way to do that every time you hit the road with your RV but I doubt the percentage of RV travelers that never do it is very high.

"The FMCSA specifies that trucks (and other vehicles, for that matter) cannot operate with tires inflated to under the pressure specified for the load they are carrying. An inspector will measure for cold inflation, and if the truck has been running, they’ll use a formula to correct for any increase in the pressure from heat. "

I don’t put the minimum amount of air required to carry the weight based on the chart, but I don’t inflate to 80 if it only needs 50 either. I used (past tense because i pretty much have in my head what I want pressures to be now days) the chart to understand what pressures need to be, then I adjust to what works well for feel, tread contact, and wear. I just provided this chart so the OP could understand why one size doesn’t fit all. Yes, these threads/discussions can go on and on and they can get deep. The OP could simply follow what is on his door sticker, or as others do, go with what’s on the tire sidewall and be fine. If someone wants to learn and understand tire pressures, there’s more to it than a door sticker or sidewall max psi.

My truck door sticker says to inflate the rear tires to 75 psi, my rear axle empty weighs 3440, my tires will carry 3470 each at 75 psi. Since I’m not driving on just one tire, I don’t run them at. 75. I actually run 65 empty, which is still rated for 3195 each. Way overkill, but gives a better ride and tire wear than 75 psi. The sidewall pressure is 80 psi which is 3640 lbs. loaded, I’m at 6010 lbs. Again, sidewall pressure is overkill and I’ve found that 75 psi gives me a better contact patch/wear and still almost 1,000 lbs of reserve. That’s just my truck/tire/trailer weight combos, and that’s what works for me

[flybouy]

So often I read the "experts" talk about trucks (commercial) airing their tires according to the weight of the load. I've seen large freight terminals with hundreds of trailers. I've seen trucks lined up at the Port to load a container. I've seen deliveries at resturants under construction of tons of equipment. I've seen trucks load large equipment at construction sites. I've seen trucks loaded with coal or timber. But I've never seen a driver airing down, airing up, or even checking the truck's tires past hitting them with a "thumper".

Am I missing something? Just curious what the reality of this is.

[bsmith0404]

Originally Posted by flybouy

So often I read the "experts" talk about trucks (commercial) airing their tires according to the weight of the load. I've seen large freight terminals with hundreds of trailers. I've seen trucks lined up at the Port to load a container. I've seen deliveries at resturants under construction of tons of equipment. I've seen trucks load large equipment at construction sites. I've seen trucks loaded with coal or timber. But I've never seen a driver airing down, airing up, or even checking the truck's tires past hitting them with a "thumper".

Am I missing something? Just curious what the reality of this is.

There’s a big difference in owner operators who pay for their equipment than fleet drivers who just want to get on the road and get paid for the mile without any concern/consideration for operating costs.

[travelin texans]

Pathman,
If I were you with your obvious limited towing experience make it easy on yourself. Get the inflation from the placard, if original size tires, along with the sidewall pressures, in the morning (cold pressures as recommended) check all tires on the truck & inflate no less than placards & no more than the sidewall then do your own research on pressures between those 2 numbers to find the inflations that work best for YOU! You should be safe at either pressures & shouldn't hurt the tires in a few hundred miles trying it out.
I never bought into the inflation by weight theory, every time the DW added a pair of shoes or I needed a couple more blocks for leveling in theory you'd have find scales to reweigh & adjust tire pressures AGAIN! Way too much weighing, pressuring up/down & too much headache doing both for 5 to 10 PSI.
Most truckers, whether owner operators or fleet drivers, are going to load that truck to the absolute max weight that's legal, or as much as they think they can get away with, so therefore will be airing their tires to the max inflation for max weight carrying, I doubt seriously you'd ever see a truck driver deflating a tire.