Tire inflation.

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With a Motor Home the only times one needs to deviate from the vehicle manufacturer's recommendations is when they find a wheel position overweight and cannot balance it out by shifting cargo. Or, when the tires are changed to another size different than the OE tires. Then there is a procedure to reset the recommended inflation pressures to the load carried by the previous tires as displayed on the certification label.

Just because a unit has heavy truck tires does not mean they are serviced like trucker's tires. They were fitted by the manufacturer in accordance with FMVSS standards and the recommendations were set in accordance with those regulations not the trucking industry regulations.

If your vehicle's certification label says it comply's with FMVSS standards read the following references because they are what was used to certify your vehicle.

https://www.gpo.gov/fdsys/pkg/CFR-2011-title49-vol6/xml/CFR-2011-title49-vol6-sec567-5.xml (This is part 5 of 7).

https://www.gpo.gov/fdsys/pkg/CFR-2011-title49-vol6/xml/CFR-2011-title49-vol6-sec571-120.xml

 
The way I look at it, we can listen to the government or we can use common sense.
 
markbarendt said:
To be fair inflation to the pressure indicated on the side wall is not going to cause a blowout. Under inflation can overheat a tire and cause a blowout.

Over inflation will though make for a poor ride, can seriously degrade vehicle handling, and will generally cause improper tire wear.

Over inflation can be defined as having too much pressure for a given load. The maximum pressure listed on the side of the tire is proper only if the maximum load is actually on the tire, for lighter loads one should weigh the vehicle and consult the tire manufacturer's weight & pressure tables.
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+1  Lots of truth in that ^^^^
 
markbarendt said:
To be fair inflation to the pressure indicated on the side wall is not going to cause a blowout. Under inflation can overheat a tire and cause a blowout.

Over inflation will though make for a poor ride, can seriously degrade vehicle handling, and will generally cause improper tire wear.

Over inflation can be defined as having too much pressure for a given load. The maximum pressure listed on the side of the tire is proper only if the maximum load is actually on the tire, for lighter loads one should weigh the vehicle and consult the tire manufacturer's weight & pressure tables.
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My apologies for providing improper information while trying to show disdain for total and utter ignorance about the facts presented in this thread. If I had known someone was going to pick apart what I said, I would have been more careful with my post. Unfortunately, I fear you missed my entire point.
 
92GA said:
  Wrong !
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Right!!! Always use the recommended tire PSI written on the tire. Anybody saying other wise doesn't have a clue. anything else is dangerous, voids tire warranty and vehicle manufacture warranty. That is FACT. Years ago Ford recommended a different pressure than Firestone tires they provides on their Bronco and it caused several wrecks and deaths it was a big law suit. What is written on the tire is what it should be it is not a suggested PSI, it is not a minimum PSI, or a Maximum PSI, it by no means is a you figure it out PSI  anything else you're playing with fire
 
aquadave said:
Right!!! Always use the recommended tire PSI written on the tire. Anybody saying other wise doesn't have a clue. anything else is dangerous, voids tire warranty and vehicle manufacture warranty. That is FACT. Years ago Ford recommended a different pressure than Firestone tires they provides on their Bronco and it caused several wrecks and deaths it was a big law suit. What is written on the tire is what it should be it is not a suggested PSI, it is not a minimum PSI, or a Maximum PSI, it by no means is a you figure it out PSI  anything else you're playing with fire
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You're wrong Again.  The number on the side of the tire is the Maximum tire inflaction psi setting that you need in order to get the Maximum load rating of the tire!  I have, on my 2011 F250 Diesel truck, a set of 275/70R/18 tires.  They are "E" rated tires and have a Maximum psi of 80 lbs....and that will give me Maxumum load of 3640 lb per tire.  The yellow sticker on the door of the truck say to inflate the Front tires to 65 psi and the Rear tires to 65 psi.  If I went to 80 psi, yes the tire would handle that.....it what it's designed to handle as a MAXIMUM pressure.  It would also give me 7280 lbs for the rear of the truck,  which exceeds the Rear Axle GAWR (6100 lbs)...by 1180 lbs. 

I'm not sure where you are getting you information from, but the number on the side of the tire is the Maximum inflation psi for the tire.....it's that simple!
 
Right!!! Always use the recommended tire PSI written on the tire. Anybody saying other wise doesn't have a clue.
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Hmmm... I'd think the tire manufacturer has some idea of how his tires behave and hold up under varying conditions, especially compared to someone not in the tire business, and even more especially compared to some lawyer who is looking for money, period.
Years ago Ford recommended a different pressure than Firestone tires they provides on their Bronco and it caused several wrecks and deaths it was a big law suit.
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That was certainly a case of underinflation, but it doesn't mean you use the MAX on the sidewall. I can tell you from personal experience how much handling is affected by overinflation -- one case was the loss of traction in very light snow when a fast oil change place ran my tires (Ranger pickup) up to the 45 psi on the sidewall, and argued as you do (I've never been back there), when pressure should have been 35 psi (not only handling, but tire wear, too). Another was on a brand new 34 foot Bounder gas coach that, when I hit a certain bump on the Interstate (not construction stuff, but a joint), almost threw me out of control. Bringing the pressure back to the tire manufacturer's recommendation for the weight, allowed that bump to be almost as innocuous for the Bounder as it was for my pickup.

If you use that philosophy on cars, then I suspect you get your tires wearing out in the center first.
 
I'm on a bunch of motorcycle forums also, and that is a hot topic of discussion on many of them.  It's the very same deal, sidewall pressure vs. loaded pressure.  The sidewall pressure is for loading the motorcycle at the full rated capacity....passenger, saddlebags and cargo.....the total poundage on the motorcycle minus what the motorcycle weighs from the factory with a full tank of gas, oil, battery, and coolant.

I'll give you an example for the rear tire of my track/race bike.  Sidewall is stamped/molded into the tire....42 psi.  When leaving the paddock on a cold tire, the rear tire pressure is..................18-19 psi.  Yep, that's not a mistake, 18-19 psi.  As the tire warms up to proper operating temperature 160 - 200 degrees "F", the pressure will go up to right at 25 psi.  Anything higher than that and you start getting heat tearing in the tires.  And just so you know, I have a tire pressure gauge that is accurate to 1/2 of 1%  plus or minus.  I also use a probe type pyrometer to stick the tire as soon as I come off the track.
 
xrated said:
You're wrong Again.  The number on the side of the tire is the Maximum tire inflaction psi setting that you need in order to get the Maximum load rating of the tire!  I have, on my 2011 F250 Diesel truck, a set of 275/70R/18 tires.  They are "E" rated tires and have a Maximum psi of 80 lbs....and that will give me Maxumum load of 3640 lb per tire.  The yellow sticker on the door of the truck say to inflate the Front tires to 65 psi and the Rear tires to 65 psi.  If I went to 80 psi, yes the tire would handle that.....it what it's designed to handle as a MAXIMUM pressure.  It would also give me 7280 lbs for the rear of the truck,  which exceeds the Rear Axle GAWR (6100 lbs)...by 1180 lbs. 

I'm not sure where you are getting you information from, but the number on the side of the tire is the Maximum inflation psi for the tire.....it's that simple!
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LOL Lug nuts don't need to be as tight as they say, only fill your radiator 1/2 full in the winter so it heats up faster, while you're at it switch out your motor oil for 85-140 gear oil it's thicker so it'll stick better and raise your oil pressure and rewire your batteries to series instead of parallel  instead of 12 volts you'll have 24-36 your head lights will be much brighter. The question is where are you getting your information from? because it is not a reputable auto or tire organization. Fact is the tire manufacture knows more about their product than you me and everybody on this forum combined If you want to take a chance on your equipment and your life that's you but you shouldn't recommend on a public forum anything other than manufacture recommended specs. Unless you're a professional driver like NASCAR Drag racing 4x4 you inflate to the pressure stated on the tire
 
aquadave said:
LOL Lug nuts don't need to be as tight as they say, only fill your radiator 1/2 full in the winter so it heats up faster, while you're at it switch out your motor oil for 85-140 gear oil it's thicker so it'll stick better and raise your oil pressure and rewire your batteries to series instead of parallel  instead of 12 volts you'll have 24-36 your head lights will be much brighter. The question is where are you getting your information from? because it is not a reputable auto or tire organization. Fact is the tire manufacture knows more about their product than you me and everybody on this forum combined If you want to take a chance on your equipment and your life that's you but you shouldn't recommend on a public forum anything other than manufacture recommended specs. Unless you're a professional driver like NASCAR Drag racing 4x4 you inflate to the pressure stated on the tire
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If that were true, why do tire manufacturers publish charts that show the recommended inflation PSI needed to support a given weight ranging from well under the tire's maximum rating up to the max rating? Are they "playing with fire" too?
 
Actually the problem was with Ford Explorers and Firestone ATX and ATX II tires, in size P235/75/15, 1991 to  time of recall, and all Firestone Wilderness AT  tires in size P235/7515. (A total of about 14.4 million tires).Broncos were not involved.
 
You also have to remember that the tire manufacturers don't know what vehicle a certain tire is going to be used on, since one tire can fit various vehicles with different weights, suspension types, handling characteristics/abilities, FWD/AWD/2WD/4WD, etc. The idea that one tire pressure setting fits all doesn't work. Also, the idea that the tire pressures recommended by the car/truck manufacturer who have designed the vehicle from the ground up and have worked in conjunction with tire manufacturers and others should be totally ignored is, to me, a bad idea.
 
aquadave wrote:
The question is where are you getting your information from? because it is not a reputable auto or tire organization.
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This would be one of probably hundreds out there, but since they are a tire manufacturer, I don't know if I would trust them or not....

http://www.maxxis.com/trailer/trailer-tire-loadinflation-chart

aquadave wrote:
you shouldn't recommend on a public forum anything other than manufacture recommended specs.
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This would actually be pretty funny, except that in your mind, you are serious.  What the manufacturer recommends is actually to use the number on the sidewall if you are needing the full tire load capacity for your application!  Period!  If it were as you think it is, why would Ford clearly state on the door pillar sticker for the tire pressure (front and rear) of my truck to be inflated to only 65 psi, when clearly, the tires that came on the truck (OEM tires, not aftermarket) are rated for 80 psi?  Would they purposely try to get me to underinflate me tires.....after all, the tire sidewall says 80 psi?  What could Ford possibly have in mind here?  Do they just not like me and all of their millions of customers that purchase their Ford products for towing heavy trailers?

Seriously, you really need to dig in and do some research before you state on a public forum your mis-information!  And as far as voiding the tire warranty for not running the sidewall pressure....Wrong Again sir!

Here is a little snippet from Tire Rack, hopefully they are credible enough to be considered "someone in the know" when it come to tires, as they deal with many brands of the black, round doughnuts....

Quoted from a Tire Rack article....

https://www.tirerack.com/tires/tiretech/techpage.jsp?techid=196

Maximum Inflation Pressure
A tire's maximum inflation pressure is the highest "cold" inflation pressure that the tire is designed to contain. However the tire's maximum inflation pressure should only be used when called for on the vehicle's tire placard or in the vehicle's owners manual. It is also important to remember that the vehicle's recommended tire inflation pressure is always to be measured and set when the tire is "cold." Cold conditions are defined as early in the morning before the day's ambient temperature, sun's radiant heat or the heat generated while driving have caused the tire pressure to temporarily increase.

Maximum Inflation Pressure
A tire's maximum inflation pressure is the highest "cold" inflation pressure that the tire is designed to contain. However the tire's maximum inflation pressure should only be used when called for on the vehicle's tire placard or in the vehicle's owners manual. It is also important to remember that the vehicle's recommended tire inflation pressure is always to be measured and set when the tire is "cold." Cold conditions are defined as early in the morning before the day's ambient temperature, sun's radiant heat or the heat generated while driving have caused the tire pressure to temporarily increase.
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NY_Dutch said:
Maybe he'll find this one more acceptable:

Load and Inflation Tables for MICHELIN? RV Tires

Or not...  ::)
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Dutch, don't get your hopes up!  We had a guy on one of the motorcycle forums that I moderate, buy a brand new bike during the winter months.  The dealership inflated the front and rear tires to the sidewall pressure (42 psi) and the guy left the dealership.  He had a cold tire crash less than 1/2 mile from the dealership while making a left turn from a stoplight.  Road conditions were dry, the pavement temperature was ambient with the outside air, the the tire was over-inflated, thus slippery, and he low-sided his brand new bike. 
 
xrated said:
Dutch, don't get your hopes up!  We had a guy on one of the motorcycle forums that I moderate, buy a brand new bike during the winter months.  The dealership inflated the front and rear tires to the sidewall pressure (42 psi) and the guy left the dealership.  He had a cold tire crash less than 1/2 mile from the dealership while making a left turn from a stoplight.  Road conditions were dry, the pavement temperature was ambient with the outside air, the the tire was over-inflated, thus slippery, and he low-sided his brand new bike. 
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Yeah, I'm not holding my breath...  ;D
 
I looked at the sidewall print on the Goodyear tires on my work vehicle (new body style Ford Explorer), and it has a warning about underinflation/overheating risks... which I think is what aquadave was getting at.  But the Goodyear tire also says plain as day that the "vehicle manufacturer owner's manual or vehicle placard" should be followed to determine correct tire pressure for my vehicle.  Since any given tire can be installed on dozens, if not hundreds, of different make/model vehicles... it seems that they would certainly not all require maximum pressure.  That would result in some pretty harsh rides.
 
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