When to read tire presure cold or warm

[Golfer Guy]

As tire pressure goes up after driving and warming up, when should one fill to recommended tire pressure warm or cold?

Had "Escapees Smart-weight" weigh my coach all four corners. Recommended 95lbs front and 100lbs on the rear. Added TPMS this winter. Going to get a compressor that will work on these 22.5" tires.

In looking at the front steer tires they are wearing on both inside and outside edges with the middle showing very little wear. Concerning to me. Need to understand why. These are Goodyear tires not sure how many miles are on them but I have put 20K on them in the past two years.

Just trying to understand and be safe on the road.


thanks in advance for your input.

[scbwr]

Tires should be inflated when cold. I think wear on both outside and inside tread can be caused by under inflation.

[Mr_D]

After sitting overnight or not driven more than one mile is what the tire companies say.

[dexters]

Originally Posted by Golfer Guy

As tire pressure goes up after driving and warming up, when should one fill to recommended tire pressure warm or cold?

Had "Escapees Smart-weight" weigh my coach all four corners. Recommended 95lbs front and 100lbs on the rear. Added TPMS this winter. Going to get a compressor that will work on these 22.5" tires.

In looking at the front steer tires they are wearing on both inside and outside edges with the middle showing very little wear. Concerning to me. Need to understand why. These are Goodyear tires not sure how many miles are on them but I have put 20K on them in the past two years.

Just trying to understand and be safe on the road.


thanks in advance for your input.

First - get yourself a good tire pressure gauge. Like this one:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Second, COLD, in the morning before the sun affects the tire temps. If the sun has shone on a tire for awhile it will be affected by the sun.

Third, tire pressure by the mfg is given at sea level, altitude affect the tire pressure you should use.
https://www.tirerack.com/tires/tiret...jsp?techid=167


That is all you really need to know. However, if you are going from a cold place at sea level (and up the PSI to the mfg recommendation) and then go to a warm place at a much higher altitude you could be over the mfg recommended psi - even at the local cold tire temperature.

[wingnut60]

Generally, tires wear on outside edges evenly from underflation; in the center ribs from overinflation.

[Dutch Star Don]

"Golfer Guy".....I had a 36' Monaco DP with the Goodyears on it. 95psi is a little low on the front of your coach, most likely causing your under inflation wear. I would raise that pressure to about 105psi. They recommend that the Goodyear G670's be run about 5psi over the recommended pressure.

If you're running more than the 95psi recently recommended, (causing the current tire wear) you need to run about 10 psi higher than what they were previously set at.

Here's a little secret. When these big tires are run underinflated, you can actually smell burning rubber when you stop the coach after a long drive. You're smelling the tire rubber being scuffed off. So.....if you smell rubber, you're under inflated. Even if you correct the psi, those front tires will still wear similar to what they are now, just a little slower. As a tire goes down the road, areas of unusual wear, like the wear on your outer edges, actually scuffs versus wearing like the center of the tire. A tire scuffs rubber off faster than it wears rubber off.

[marknpeg]

I went by my weight results the Michelin inflation tables when I set my tire pressures, initially on a cool morning, probably 45-50 degrees. Set the fronts to 112 and the rears to 95. That resulted in running pressures of 125/105 or so. After runs to Charleston and Orlando in February (much warmer temps), I saw my running pressures increase to 128/108, so I took about 7 pounds of of them (while warm) and my last run had running pressures around 121/102. The coach was a bit more stable, but oddly enough I did catch a whiff of rubber smell at one point. I find it very hard to believe that I'm underinflated, but willing to listen. The tires only have about 4,000 miles on them, so there isn't much wear to speak of yet.

We're headed to KY on Saturday where it will be cooler again, so I may raise the pressures back to the original levels.

[Sandy Swede]

Originally Posted by dexters

First - get yourself a good tire pressure gauge. Like this one:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Second, COLD, in the morning before the sun affects the tire temps. If the sun has shone on a tire for awhile it will be affected by the sun.

Third, tire pressure by the mfg is given at sea level, altitude affect the tire pressure you should use.
https://www.tirerack.com/tires/tiret...jsp?techid=167


That is all you really need to know. However, if you are going from a cold place at sea level (and up the PSI to the mfg recommendation) and then go to a warm place at a much higher altitude you could be over the mfg recommended psi - even at the local cold tire temperature.

x2 on the Accutire gauge. Also, thanks dexters for the link on effects of altitude and temp on air pressure. We are a few feet above sea level for most of the year and like to spend the summer and fall in the Rockies. Good stuff to know.

[Bigd9]

Originally Posted by Golfer Guy

As tire pressure goes up after driving and warming up, when should one fill to recommended tire pressure warm or cold?

Had "Escapees Smart-weight" weigh my coach all four corners. Recommended 95lbs front and 100lbs on the rear. Added TPMS this winter. Going to get a compressor that will work on these 22.5" tires.

In looking at the front steer tires they are wearing on both inside and outside edges with the middle showing very little wear. Concerning to me. Need to understand why. These are Goodyear tires not sure how many miles are on them but I have put 20K on them in the past two years.

Just trying to understand and be safe on the road.
thanks in advance for your input.

I'm so glad you got the 4 corners weighed and received actual factual information on the required tire pressures. Your pressures are in line with what many other use. You can't beat hard facts. That is, tire pressures are directly related to the load on a tire, the manufacture and the tire size. You can increase the tire pressure if you want, but all you will gain is a harsher ride and less tire traction. As has been said here already, the higher the tire pressure over the factual pressure the center of the tire bulges out , thus decreasing the contact area the tire makes on the road.

I will make a couple observations. One is the age of your coach. Are your tires original? If so that makes them 11 years old and you should be thinking about replacements.

Second is the tire brand. My 2006 coach came with Goodyears and they were wearing along the edges also. The wear pattern was a wavey & odd looking. It is a well known problem called "Rivering" and for some reason Goodyear tires seem prone to this. I replaced my tires last year with Bridgestone Tires and that one change made all the difference in the world!

Here is a picture of a Goodyear tire with Rivering I found on the Net. Mine looked very similar to this.

[Golfer Guy]

I want to tank all of you for your info and good advice. Looking at my tire wear it is very similar to the picture of rivering in the last post. I do think it is time for some new shoes on the front. The DOT is 4510 so they are 6 1/2 years old with probably 25-30K miles on them. My rear tires are DOT 1014 and in great looking shape.

I might ask those of you what tires you would recommend for this 06 38' Beaver? I will also post that question in its own thread.

As for pressure on the fronts I think I will add some extra to 100lbs, five over the SmartWeight recommendation.

Thanks again, great site this IRV2.com

Steve

[Dutch Star Don]

"Golfer Guy".....Over the years, many people have complained of "rivering". The picture that "BigD9" posted is a perfect example. You actually see the "river" pattern in the wear. Only the Goodyear G670's do this. Often when this issue comes up, you'll have some guys come on and say that they've never experienced rivering and everyone who says it's an issue is making it up.

After reading articles about it for years, I made a discovery as to why some have the issue and some don't. If you go back and read complaints about rivering, 90% of those are made by Monaco brand owners. Apparently, the Roadmaster chassis with their big floating "H" designed front end, did not play well with the Goodyear tires.

So......whatever you buy, don't buy Goodyears for the front of a Monaco coach with the Roadmaster chassis. After two pairs of Goodyears (got 20K each before they had issues) on my Diplomat, I went with the Hankook AH12 tires. I really like the quality of Hankooks and recently put them on a Honda CRV to improve the rough ride and reduce tire noise. Their 22.5 tires are about half the price of Michellin or Goodyear.

The problem with the Hankooks......they come in limited sizes. You might have to go with Michellin or look at something like the Toyos.

[MSHappyCampers]

Originally Posted by Mr_D

After sitting overnight or not driven more than one mile is what the tire companies say.

Agree!

[Mr_D]

Originally Posted by marknpeg

I went by my weight results the Michelin inflation tables when I set my tire pressures, initially on a cool morning, probably 45-50 degrees. Set the fronts to 112 and the rears to 95. That resulted in running pressures of 125/105 or so. After runs to Charleston and Orlando in February (much warmer temps), I saw my running pressures increase to 128/108, so I took about 7 pounds of of them (while warm) and my last run had running pressures around 121/102. The coach was a bit more stable, but oddly enough I did catch a whiff of rubber smell at one point. I find it very hard to believe that I'm underinflated, but willing to listen. The tires only have about 4,000 miles on them, so there isn't much wear to speak of yet.

We're headed to KY on Saturday where it will be cooler again, so I may raise the pressures back to the original levels.

The tire companies say do not reduce the tire pressure when the tire is hot. The tires are designed to accept the higher pressure from heat buildup.

The tire companies put all this information in their booklets, doing a search will usually find them.

Also, some manufacturers, Country Coach was one, have changed their stance on tire pressure. Here's what my owners manual says:

Tire Industry Changes
The tire industry, as a whole, has changed its traditional stance on adjusting cold tire inflation pressure for RV tires installed on recreational vehicles and busses. Previously, tire manufacturers supported a policy where tire inflation could be adjusted according to the actual loaded weight of the vehicle. Now, the major tire manufacturers recommend that medium duty truck tires be maintained at the pressure that corresponds to the Gross Axle Weight Rating for the axle to which they are mounted. To make this recommendation uniform across the industry, tire manufacturers strongly urge the consumer to keep all tires inflated to the pressures recorded on the Federal Tire Label.

Tire Inflation
Country Coach recommends that the cold tire inflation pressures should at all times be maintained at the inflation pressure(s) recorded on the Federal Tire Label. There are no acceptable circumstances where tire inflation pressure(s) should be reduced below that pressure recorded on the Federal Tire Label.

[Dukerdr]

I've always followed a "10% rule" about inflating tires. Whether I was leaving the house with a loaded vehicle, or setting the tire pressure on a motorcycle.

If, after a proper warm up, the tire pressure rises more than 10%, you need a couple more pounds when cold.

This is nothing I was told by tire technicians at Auto + Truck tire shops, they all seem clueless. "Just run the maximum shown on the sidewall..." many will say.

But over 30 years ago when I was roadracing motorcycles, the old Dunlop tire rep at Daytona taught me the 10% rule. I've followed it on everything since then.

Yes, it can be a pain to stop 30 minutes into a trip to check pressures before continuing.
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