Tow Vehicle tire inflation
 

WEll- I googled this and found endless "discussions" on the Web. I'm running Goodyear Wrangler ATS on my 97 150 4x4. max sidewall rating on those tires is 44PSI. The "door" pressures, however, say 29 front and 32 rear-of course, the Goodyears are not what the F150 came with.

Some say run door pressure regardless- others say they run maximum sidewall pressure when towing. Right now I'm splitting it a bit---

What does everybody here say?

Rick

if able try to go and have it checked out at a tire store or a similair place for there determination, when it comes to tires, a easy blow out can occur from improperly or over inflating, and towing a unit with a heavy hitch is not safe.

Rick, Goodyear should publish the max load rating of those tires when inflated to a particular pressure. I know they are considered "safe" if inflated to the max cold pressure of 44 psi, but they could wear more in the center of the tread.

I suspect the rated load for those tires is at 40 psi cold. If this is the case, that pressure is what I would put in them.

My tires are Goodyear Wrangler Silent Armor, 44 psi max pressure. They are the same size and very similar to the OEM tires that were on the truck which had a recommended pressure of 40 psi. I keep them there.

- Jack

Rick, I have a 2000 F250 4x4 7.3L and a heavy duty camper shell on the extended cab. Based on this, I generally run 65 PSI due to the heavy weight of the Ford Truck. When towing the Hi Lo, I will add about 5 pounds to that. Door Pressure states 70 PSI on my truck.

I don't know if this is the place to put the following information but I thought it would be good for Hi Lo owners to be aware. It deals with tire pressure on our Hi Lo's and what I have found through research:

Tire Pressure on Hi Lo:

I used this method to determine the weight and tire pressure ratio for a new set of 8-ply tires I had mounted this month. I researched before having the tires mounted. I tried to find the URL link information from an ‘expert’ tire professional but could not find it. I will condense the main points since I did copy and print it out at the time:

“When you get new tires mounted and they don’t ask you how much air for your tire, they will arbitrarily put the recommended maximum pressure allowed in the new tire. This causes over inflation that you may not require for the actual load. If you run the maximum pressure, it will cause unnecessary tread wear in the center area of the tire. From a safety standpoint, since you do not have a good ‘foot print” and the tread is not making even contact with the road, you have reduced its braking ability and that causes instability”.

He goes on to say; “let’s say you have a trailer weight of 4,000 pounds on a two axle trailer; that means the 4 wheels will be bearing 1000 pounds of distributed weight each. If you look at the chart [for a 205 75R 15], a tire pressure of 25 to 30 pounds will easily handle that weight and give you a good ‘foot print’ and soft ride”.

Armed with this information, when I took my trailer down to get it inspected and have the new tires installed, I provided this information to the manager of the tire shop and he agreed, that is what generally takes place. He also agreed that since I put 8-ply tires on, the maximum pressure of 65 pounds was completely unnecessary for the weight of the Hi Lo. Based on this, we agreed the ideal pressure, plus a little extra since I did not know what the exact payload would be, should be right at 40 PSI which he placed on the work order. Sure enough, when they finished mounting the tires, I asked one of the guys to check the tire pressure. Yep, they had placed 65 PSI in each tire. I watched as they reduced each tire’s pressure down to 40 PSI.

I don’t know if the forum has ever addressed this before but I would be willing to bet that a great majority of all Hi Lo RV owners are running around with over inflated tires.

The maximum load rating per tire for the Hi Lo trailer with two axles [4 tires] ST205-75R-15 for:
Load Range C 6-Ply = 1820 lbs. with maximum 50 PSI Maximum speed rating 65mph
Load Range D 8-Ply = 2150 lbs. with maximum 65 PSI Maximum speed rating 65mph

My 2406 Towlite weighs 4525 with an expected gross loading weight of around 1400 pounds; Total weight 5925 Average Loaded Vehicle Weight per axle = 1481 lbs. Since I am running 8-ply tires, my ideal pressure with the load I carry would be somewhere between 35 to 40 pounds.

Don’t ask me why I’m running 8-Ply [Load Range D] when I will never exceed the load recommended for 6-Ply, load range “C”, but I suppose it is knowing I have an extra 2 ply’s and on the occasions I do exceed 65mph, they will handle the speed and heat load better. Also, the manager made me a real good deal on a set of [4].;)

Maxxis has a graduated chart with different sizes shown here:

https://www.maxxis.com/Repository/Files/m8008load.pdf

Jerry Curtis
2406 T

Thanks for posting that, Jerry. I ran a search but didn't find much in the forum on tow vehicle inflation- though I know there have been discussions on the trailer tires. Actually- I get confused by a lot of this...but your post and jack's helped.

There are trail americas on my trailer, now, and they show a max load rating per tire of 1350. I don't know what came with the trailer new, but these are on there now and they are 175/180 13. i don't know the load rating as I don't where on the tire it is listed. My eyes are bad enough now that I need a magnifying glass to read all that stuff anyway. But- max sidewall pressure is 50psi, cold. i assume that would be at 1350 lbs of payload per tire. Dual axle, four tires, and a GVWR of 4500lbs- which is a bit strange as the trailer sticker lists 2200 lbs per axles. I guess tw doesn't count? But- that would put the max per tire @ 1125 if loaded to max weight. Clearly, the 1350 gives me some safety room, I guess. The HI-Lo sticker says the tires should be at 35psi- and when I got it that is where they were at. All sort of posts on the web say run your trailer tires at the max, so last time out I put them at 50psi. Some how during the last moth of sitting I've lost 5lbs- so I am thinking of just running them, there, at 45. On the truck I kicked everything up to 38. The only logic, here, is that I'm splitting the difference of some of the suggestions I have gotten and it makes sense for me to increase inflation when I am increasing load---but, again, it is just something I have tended to do most my life and I really cannot say where I picked that idea up.

Anyway- the one annoying aspect of this Hi-Lo is the GVWR. Options installed include stableizer jacks, roof AC, Awning, electric ATWOOD front jack- and an extra battery. With both propane tanks filled and options it comes in right around 4000, which is why I have taken to loading food, chairs, clothing, and everything else in the truck when we go. 500lb of scrunch room doesn't leave me much---though, admittedly, 500 lbs of food and clothing should get us through most winters without re-supplying.:rolleyes:

Your chart is helpful. It might be an interesting thread to post and keep going for awhile because opinions seem quite varied.

Thanks,

Rick

I posted a chart relavent to tire pressure and load dependent on tire size.
https://www.airforums.com/forums/atta...chmentid=16648
A properly inflated tire will have the most efficient tire foot print meaning the weight per square inch of rubber to pavement, either to much air or not enough will reduce this foot print, resulting in poor handling, traction and stopping and wear. To arbitrarily put a certain air pressure is a gamble.
I towed a 30 foot award 730 for quite a few years with a 1997 F150 supercab with a fiberglass case. If you look at the trailer sticker it states 5200 lbs, the truck weight was published at 3400 lbs and the cap was probably another 300 lbs so roughly 9000 lbs plus myself and wife and other stuff. My truck was list as a gross combined weight of 11, 000 lbs, so I felt I was within limits.
Entering Colorado I read the sign stating all vehicle trailer combination must get weighed so I pulled in amongst the semis. The operator of the weight station flagged me through but I requested to be scaled. To my surprise I weighed in at a gross of 10,800 lbs, 4800 on the trailer axle and 6000 on the truck. Now using that info it means 1500 lbs per truck tire and 1200 pounds per trailer tire.
You would use these weights plus a little fudge to figure what pressure would be recommended. I for years used the max 50 pounds in the marathon trailer tires I the dropped it down to 36 pounds allowing for an extra 1000 pounds in the trailer for the truck I kept the tires at 38 since max load at 2100 lbs was 44 psi
Evry tiremanufacture has this information

Ok- so far, you have me convinced to dial the inflation the trailer back. obviously, I am not carrying more than about 1000 per tire on the trailer- so the 35 it came with seems about right and Hi-lo sticker does also. The guy who traded it in was the owner of a car dealership for many years---so maybe he knew a thing or two. Still- I can't find any links to the tire mfg on my trailer.

I'm off to chase down goodyear tire chart.

Thanks

rick

The federal gov't regulates the standard on tires so they meet minimum standard so a certain tire of certain dimension meets specific specs, the only good thing about known tire manufacturers is if they have been in business for a long time they are doing somethin right and should be there down the road to stand behind their products

I always inflate my tires to 50psi. I do this for two reasons. I want to make sure I have enough reserve. The thing is this for me. I will not be visiting the CAT scales every time I load up and leave on a trip.

I have no way of knowing if the weight in my trailer is spread exactly even over the 4 tires.

Also, the sticker on the front left of my HiLo says 50psi.

I thought we were talking about tow vehicle tires, not trailer tires.

I'd be hesitant to reduce the pressure on trailer tires much. With lower pressure, they flex more which causes heating. Heat destroys tires. You don't need to concern yourself too much with traction on trailer tires, except maybe for hydroplaning on wet roads. But to counter hydroplaning, you want to use the highest pressure possible.

- Jack

@Jack

I started the thread on talking tow vehicles but it morphed into all tires a bit---jcurtis wrote:

"I don’t know if the forum has ever addressed this before but I would be willing to bet that a great majority of all Hi Lo RV owners are running around with over inflated tires.

The maximum load rating per tire for the Hi Lo trailer with two axles [4 tires] ST205-75R-15 for:
Load Range C 6-Ply = 1820 lbs. with maximum 50 PSI Maximum speed rating 65mph
Load Range D 8-Ply = 2150 lbs. with maximum 65 PSI Maximum speed rating 65mph

My 2406 Towlite weighs 4525 with an expected gross loading weight of around 1400 pounds; Total weight 5925 Average Loaded Vehicle Weight per axle = 1481 lbs. Since I am running 8-ply tires, my ideal pressure with the load I carry would be somewhere between 35 to 40 pounds. "

The post by jerry and by raamw included inflation charts- so maybe this is now a discussion on side wall markings vs charts vs general practice. That said- I found goodyear charts which covered their passenger tires and their trailer tires- so I'm wondering ,now, if your comment about not overinflating wouldn't also apply to trailer tires. AT this point- my hi-lo sticker on the 2001 says inflate to 35psi and so do the various charts. I'm still trying to interpret the good year charts for the ATS WRangler vs the door sticker on the 97' f150.

Rick

Tires are tires whether they are on a bike truck atv etc. The company that produced the vehicle know the weight of the vehiccle, they put the proper weight rating tire. For instance let say you have an F250 with an empty weight of of 4000 pounds and a Gross vehicle weight of 7000 lbs. Since the truck is rated to be a max of 7K the tires put on will be rated to carry a minimum of 7K or 1750 per tire. More than likely it will have a D rated tire with a max wight of 2150 each at some predetermined pressure. That doesn't mean you can haul 8600 lbs because was not set up to handle it (IE brakes cooling gearing ratio etc) If you check the tire charts you would look what pressure you should run to carry the load you have in this case 1800Lbs, it will be less than the max this way you get a proper foot print meaning stability, traction stopping and longevity.

At some point you must have seen pictures of tire wear for overinflated tires (worn out in the center with outside edges like new, the tire was only riding on the center until it wore down to engage the rest of the tire, loss of tire live Underinflated tire has the outside worn and the inside like new. It doesn't matter what the application is

The factory is required to list the pressure as it comes out of the factory since they are require by the fed to list the empty weight and max weight, if you add additional weight you may need to increase the pressure. How can this be done before loading weigh it, to run a couple pounds over the listed pressure is no big thing.

Once you get a general idea of what you carry will be your guide to proper tire pressure

Now if your trailer weighs 4500 empty, about 400 to 600 pounds of that weigh goes to the tow vehicle via the hitch meaning the axle weight of the trailer is now 3800 to 4100 pounds and the tow vehicle picked up this additional weight on the rear axle. If you use load bars the bars will take some of that 600 pounds and push it to the front tow vehicle tires (front end of TV goes down to maintain proper steering)and some back to the trailer. So this will change everything so keep that in mind.
What I do is at every stop I walk around and place my hands on all the tires to see if they are running hot which is an indicator of overweight, under inflation and either adjust to pressure to minimize side wall flexing or plain slow down to decrease heat build up. Heat is the leading cause of tire failure and premature tire wear.

The post by jerry and by raamw included inflation charts- so maybe this is now a discussion on side wall markings vs charts vs general practice. That said- I found goodyear charts which covered their passenger tires and their trailer tires- so I'm wondering ,now, if your comment about not overinflating wouldn't also apply to trailer tires. AT this point- my hi-lo sticker on the 2001 says inflate to 35psi and so do the various charts. I'm still trying to interpret the good year charts for the ATS WRangler vs the door sticker on the 97' f150.

Rick[/QUOTE]

Rick,

The first paragraph of my post was in response to tire pressure on TV's which I answered. The greater part of my response was actually referring to my particular Hi Lo [2406 T] and what I had found out when I researched the new tires I was purchasing.

I apologize for confusing the trailer versus TV tires; I guess I should have started another thread, I did not intend to change the discussion topic but I felt it important for Hi Lo owners to consider what I had learned from tire experts about inflating tires on a trailer.

rammw's latest post clarify's the point I was trying to make and I feel the information would be applicable to either the RV or TV.

Jerry Curtis
2406 T

The sticker on the door is the weight of the truck with all factory accessories, It is the proper PSI for that app[application, If you add equipment to the truck then you may need to adjust the pressure to compensate.
The truck company supplies the initial correct info. The tire company has no idea what that particular tire will end up on so they will supply the variable chart. Use the door sticker for starters and correct as necessary. If you change tire size the sticker will no longer apply but you should have a good guess at the weight per axle

A quick follow-up.

I was leaving on an extended couple of days trip when i started the last thread. I have not gotten back to my good year dealer,yet, as far as the truck tires go-but as far as the trailer tires were concerned---i called th dealer that sold and installed the hi-lo tires and he said inflate to maximum on those tires----that the hi-lo sticker was for origninal tires and the guy upgraded. I realize that goes against the tire charts----but the prevailing response I am finding on many forums and from others is to go with full sidewall inflationfor the trailer.

rick

Not to beat a dead horse but you are getting bad information, if what you where told is true than what is the purpose of the pressure charts.
Here is Goodyear RV tire information brochure, read it and you decide who is telling you the truth, tires are tires no matter who the manufacturer is if it is sold in this country theymust all meet the same standards as set by the DOT

https://www.goodyearrvtires.com/pdfs/tire-care-guide.pdf

It would be nice if the tire companies and the RV manufacturers got together and came up with a unified set of standards so the end users, us, would know what is right. I would say that Goodyear would know as well as anyone what is right for tires.

There is a unified standard, any company that produces a vehicle for on pavement water or air use must comply with the rules as published by the Department of Transportation. DOT regulated any and all vehicles and the manufacturers would not be allowed to sell a vehicle in this country if they did not meet these standards. There are a high number of vehicles that are produced world wide that can not be sold or licensed in this country because they don't comply with DOT standards. If you look at commercial vehicles, trucks trains planes boats etc they list the certification on their vehicles when one of them get involved in an accident the Highway/transportation safety administration conducts an investigation to determine the causes and if any rules need to be changed. Overweight trucks are generally easy to spot but trains and planes are not.
That is why the sticker lists the size tire, the max axle weight for each axle and the GVW and GVCW for vehicles that can tow.

I'm sure the manufacturers follow the standards, both trailer and tire makers, or they would be spending lots of time a courtroom. What I was meaning was that when the trailer says 50 psi and then the tire co. says that the pressure can vary for the exact same tire. I guess that when the sticker says 50 psi and tire says 50 psi max I would do 50 psi. To put variable psi on the sticker would create confusion and lots of tire failures which in turn would be blamed on the tire co. So they have to dumb it down to prevent that from happening. I suppose they could send a table of tire pressures with the tires and then when you put air in the tires you will have to weigh the trailer to get it right. How many people would actually do that?

If your trailer sticker states 50PSI, then that would be the psi it needs to be at, that tells me your trailer axles are at max weight, if not you will only get less mileage since overinflated for the load causes the tires center to wear out, if this is the case then that is a dangerous situation since the foot print of the tire has less rubber to pavement contact resulting in poor braking, skid control wind deflection etc. I would get your rig weighed at one of the truck stops that have scales ot a state weight station if they allow. I plan on doing this with my new 2510 when I take it out this way their is no guess work at all. My2510 is listed at empty weight of around 4500 pounds and a gross of 7500 with 205 R15 marathons on which has a max of 1820 lbs@50PSI (7280lbs) at empty weight the proper PSI would be roughly 30 lbs, so for me the minimum pressure would be 30 and the max 50. It looks as if I am overloaded at max but when you hook up approx 500 pounds of those weighs goes to the Tow vehicle. Figuring 90 gallons capacity (700 lbs) and probably another 1000 pounds for all the stuff you cam stuff I would be max at 6400, probably 5800 (5400 0n the ) road since I always empty my tanks for the road, my psi should be around 36 pounds minimum I would hand check the tires on the road to determine any heat build up and adjust is so needed. Also visual profile of the tire, if it is bulging on the sidewalls you should bring the pressure up since the flexing of the sidewalls causes heat build up.

I don't care what that chart says. I inflate to 50psi for each tire. To do otherwise, I'd have to run up to the CAT scales everytime I packed the trailer to go out. There is no way I can accurately "guess" at the weight the trailer is carrying every time I load.

Since I can't guess accurately, and since I'm not going to weight the TV & TT at the CAT scales every time I leave home, I'll just inflate to 50psi and forget about.

I'm also fortunate in that my smaller, shorter Tow Lite gives me a lot of "margin for error". It's GVWR is 5500#. The axle GAWR is 3500# or 7000# total. The tires are 1820# each or 7280# total. I have plenty of margin for error.

Here is a very informative article on what I have tried to convey, it is quite long but worth the read What I have referred to foot print, the author refers to it as ADHESION PATCH.
Once you have your axles weighed you will not need to do it again.

Home / Forums / General Hybrid Topics / Fuel Efficiency & Emissions /
Dangers of Over Inflating Tires

Created May 23, 2011, at 7:33 am by vtr5955

There have been many postings offering recommendations regarding increasing tire inflation to increase fuel economy. There have also been many questions about the hazards of over inflating, many inquiring about “blow out hazards.” In my opinion, most discussions on the topic of over inflation offered opinions and very little technical knowledge. I am going to offer a technical view of the topic. Increasing the blow out risk is a possibility, but the real hazards of over inflation are related to traction reduction and altered performance and handling characteristics. Traction and handling issues have a significant impact upon risk exposure.

The key to understanding the issue of inflation pressure is to understand the adhesion patch. The adhesion patch is the surface area, or patch, of tire in contact with the road. Think of being in a deep hole that is covered by plate glass and a tire is parked on the glass. The portion of the tire tread that is pressed out flat onto the glass (road surface) is the adhesion patch.

Imagine a trailer that carries a load sufficient to put a 1000 pound load onto that one tire on the glass. The tire is inflated to 30 psi. Now, 1000 lbs. divided by 30 pounds /sq. in. is equal to 33.33 sq. in. (the pounds cancel) of adhesion patch surface area. Now, double the load in the trailer. Does the tire pressure rise with increased load? No. The tire “squats” and increases the size of the adhesion patch. 2000 lbs. divided by 30 pounds /sq. in. is equal to 66.67 sq. in. The adhesion patch has doubled in size to support the doubling of the load.

The adhesion patch is also changed by a change in tire pressure. Again, assuming the 1000 pound load but increasing the pressure to 50 psi results in 1000 lbs. divided by 50 pounds /sq. in. is equal to 20 sq. in. That’s a 66.7% increase in pressure resulting in a 40% decrease in adhesion patch size. Just as important as the total surface area of the adhesion patch is the shape of the adhesion patch.

Some of us who live with seasonal snow and ice have discovered that “skinny” tires provide better snow and ice traction than “wide” tires. That means that an adhesion patch that is longer (front to back) than it is wide (side to side) provides better forward traction and stopping power on snow and ice that an adhesion patch that is wider than it is long. Increasing tire pressure decreases the length (front to back) of an adhesion patch faster that the width. In fact, it takes a massive increase in tire pressure to significantly change the width. The tire “lifts” the front and rear of the adhesion patch with increased tire pressure much more readily than it lifts the sides.

Now, this combination of causing the adhesion patch to grow smaller at the same time that it is becoming shorter has a double impact on forward traction and stopping distance. So, as a rule of thumb, one should assume that a 10% increase in tire pressure above manufacturers’ recommendations results in a 20% decrease in forward traction and a 20% increase in stopping distance.

There are other effects as well and those effects are not beneficial either. Radial tire designers stiffen portions of the sidewall and leave others flexible to keep the adhesion patch in contact with the road in a turn. As centrifugal force pushes sideways on the wheel the sidewalls of the tire will “roll” or “flex” to keep the adhesion patch on the road.

In the old days, when we drove on bias-ply tires, it was not unusual to take a curve hard and fast and find oneself turning the steering wheel further than you thought you should to keep the car on the correct arc. This “over-steer” condition was a function of “tread slip angle.” Fundamentally, the sideways centrifugal force distorted the adhesion patch such that the treads deflected into an arc. The leading edge of the arc pointed out of the turn and we needed to compensate by over-steering. Push the turn too fast and the adhesion patch would break free of the road, with undesirable results consequent.

In fact, early radial tire designs had sidewalls that were too stiff as tire designers tried to tune the tires to accommodate the soft suspensions and high roll centers typical of American cars of that era. The result was that the early radials would not “warn” the driver with an over-steer condition, it would just break free without warning. Since then, roll centers have been lowered as suspensions have become better tuned and tire designers have better balanced side wall flex characteristics.

Over-inflating a tire alters the sidewall flex characteristics as well as the operating performance characteristics of the tire. Inflate too much and the vehicle might be described as feeling like it’s riding on bowling balls. This should be a fair warning that the tire performance characteristics are not balanced with the suspension designs. It should be expected, then, that traction, stopping distance and handling characteristics have been altered to a degree that increases the risk of losing control of the vehicle.

The elevation of those risks increases the probability that the vehicle will not stop as expected and also increases the risk that the vehicle can become unstable in curves, especially on high speed roads and exit ramps.

Most troubling of all is the increased vulnerability to hydro-planing to which an over inflated tire is exposed. The shorter and smaller the adhesion patch the more vulnerable a tire is to hydo-planing, as a short adhesion patch does not have as much “time” to “squeeze” water into the tread grooves. Instead, the water will ingress between the tire tread and the road surface, literally “lifting” the tire off the road. The effect is worse than driving on black ice. It is unnecessary to explain that the consequences of such an effect are unattractive.

Do I raise the inflation of my tires beyond manufacturers’ recommendations? Yes. However, I do not over inflate more than 10%. In my FEH the recommended inflation pressure is 35 psi front and rear. That means that I inflate 110% of recommended inflation. 1.10 X 35 psi = 38.5 psi. Do I round that up to 40 psi? No. 40-35=5 and 5 divided by 35 is 14.2%, almost a 15% increase. That’s too much if I use my rule of thumb that stopping distance is increased, in percentage terms, by double the increase in air pressure, in percentage terms. Are you comfortable with a 30% increase in stopping distance? Are you comfortable with a 20% increase in stopping distance?

There will be those who refute the risk exposure by offering that, as part of their hyper-milling routine, they “drive as if they had no brakes.” That’s fine, except in a panic stop event when a driver cuts you off by merging from a side road unexpectedly. That’s fine, except when a member of the family, who isn’t as skillful a “drive as if there were no brakes” practitioner, is driving the vehicle. That’s fine, except when the driver hits a wet patch and begins to hydro-plane. That’s fine, except when the tire breaks free without warning on a curved exit ramp, that the driver takes injudiciously fast as a component of the “driving as if there were no brakes” technique.

In other words: don’t lie to yourself. If you are elevating risk by reducing traction, increasing stopping distance and unbalancing tire performance characteristics versus the suspension design – then you are increasing your risk. Steps taken within the driver’s control to reduce those risks do not mitigate the risk exposure fully. Keep in mind that a driver does not have full control of all of the risk conditions to which he or she is exposed. “Driving as though you have no brakes” is insufficient to mitigate all possible hazards.

There are many steps that we can take to increase our fuel economy that do not increase our risks. Keep in mind, the driver is not the only entity exposed to those increased risks. Family members who drive or ride in the vehicle, other drivers, their passengers and pedestrians are also being put at higher risks.

If that’s not enough to convince you then consider this: any serious accident will be investigated. If the investigating agents finds that tires are inflated more than 10% above manufacturers’ recommendations the over inflated condition will be cited as a factor contributing to loss of control or failure to stop. If your tires are inflated to 55 psi versus the manufacturer’s recommendations of 35 psi, you’re not in a good position.

What most impressed me regarding the recommendations offered for increasing fuel economy were that many of them were based upon a technical examination of the characteristics of the Atkinson cycle engine and or approaches to more fully exploit the energy stored in the HIV batteries. When it came to discussing tire inflation, however, the technical approach seemed to be absent and recommendations were offered without a technical disclosure of the elevation of risk. Increasing fuel economy by trading off safety is, in this writer’s opinion, a fool’s economy.

Obviously you have a thing for not running trailer tires at max pressure, which is fine. We will have to agree to disagree about this.

Every thing I have read with regards to underinflation and overinflation is the one to be feared the most is underinflation. It's my understanding that running under inflated tires causes excessive heat build up in the tire which may be the #1 cause of tire failure.

The biggest problem with over inflated tires is mostly early wear of the tires.

By the way, reducing air in the tire does not automatically increase the patch area. If a tire is underflated, it wears out the shoulders of the tire, and not the middle. And this would decrease the amount of patch area.

Also, I don't understand your statement that once the axles are weighed you're set, and don't have to weight them again.

What if your packing habits change. What if you decide to carry more stuff. There is no way I can guarantee that my trailer weight will be the same each and every trip.

That's why I put 50psi in them. The tire side wall says max inflation is 50psi. HiLo, on the stickers in the side of the trailer, says 50psi.

There is nothing in the owner's manual, or on the tire, or on the side of the HiLo that suggests I consult GoodYear Marathon's tire guide and change PSI depending on the weight I'm carrying that particular trip.

I don't know what year trailer you have s I don't know what the weights are, I know it may sound confusing if the the trailer states that, someone is wrong since the tire manufacturers strongly advises that you match your PSI to the load to prevent a hazardous situation. If you read the sidewall all that tells you not to exceed this pressure doesn't mean that is the pressure to use. If you read the article it seems over inflation is attributable to blow outs as must as under inflation, meaning to me that the proper inflation is the only safe way to go.

In all my years of trailering I scaled my last trailer and was surprised at the weight on the axles, even if I changed what I was hauling I doubt if I would increase it by a 1000 pounds which would only be a tire increase of 250 per tire so after the initial weighing I would not bother to rescale.