How old are your tires?

[Tireman9]

Originally Posted by kidoo

I don't think there is any warranty for cooper RV/truck type tires. The cooper warranty seems to only apply to passenger and light truck vehicles.

I did check other brands at twice+ the price, Michelin or Goodyear for example, that have warranty and found that you really have to read ALL the exslusions. Ozone or weather cracking on Michelin are excluded..., irrugular wear for Goodyear are excluded...

No Warranty from Cooper and no local support from Les. Looks like you might have saved a bit too much $ with the purchase.

Michelin, Goodyear & Bridgestone / Firestone all have nationwide service and truck tire warranties.

Service and warranty coverage were mentioned as important considerations in my blog post of how to select the "Best Tire"

[kidoo]

Tireman, I am no expert in tires but what I read on truck tire website about warranty does not seem to cover much. Maybe you can explain what is warranty exactly?

For example, Michelin are not covered for cracking and I think this is their worst weak point, Goodyear are covered for cracking. Goodyear are not covered for uneven wear, and they are know to have uneven wear and cupping, mine did.

I did check your Blog and you mention about Tire sensors, I think this would be my best warranty. I had a blowout on a tire that was slowly loosing air.

Here are two examples from their Website

http://www.michelintruck.com/assets/...e_Warranty.pdf
Michelin:
WHAT IS NOT COVERED
Tires/casings which become unserviceable due to:
– Road hazard injury (e.g., a cut, snag, bruise, impact damage or
puncture);
– Incorrect mounting of the tire, tire/wheel imbalance, improper
retread or improper repair;
– Misapplication, improper maintenance, racing, underinflation,
overinflation or other abuse resulting in casing damage or fatigue;
– Accident, fire, chemical corrosion, contamination, tire alteration
or vandalism;
– Flat spotting caused by improper storage;
– The addition of liquid, solid or gaseous materials other than air,
nitrogen or carbon dioxide;
– Uses other than long haul service for any extended warranty
casing claims;
– Uneven or rapid wear caused by mechanical irregularity in the
vehicle, such as wheel misalignment, resulting in damage to the
under-tread, carcass or steel belts;
– Ozone or weather checking.
http://www.goodyeartrucktires.com/pd...ty_10_2015.pdf
Goodyear

WHAT IS NOT COVERED UNDER
THIS LIMITED WARRANTY?
• Wear conditions or tire damage due to road hazards
(including punctures, cuts, snags, impact breaks,
etc.). Wreck, collision, or fire. Fast wear, irregular wear,
heel and toe wear or other wear conditions.
• Improper inflation, overloading, high-speed spinup,
misapplication, misuse, negligence, racing, chain
damage, or improper mounting or demounting.
• Mechanical condition of the vehicle.
• Chip/chunk conditions on tires intended for
highway service.
• Ride disturbance after the first 2/32" (inch) treadwear
or due to damaged wheels or any vehicle condition.
• Any tire intentionally altered after leaving a factory
producing Goodyear tires to change its appearance
(example: white inlay on a black tire).
• Tires with weather cracking which were purchased
more than four (4) years prior to presentation for
adjustment. If you have no proof of purchase date,
tires manufactured four (4) or more years prior to
presentation are not covered.
• Material added to a tire after leaving a factory
producing Goodyear tires (examples: tire fillers,
sealants or balancing substances). If the added
material is the cause of the tire being removed from
service, the tire will not be adjusted.
• Any Goodyear Commercial Truck tire with the word
“Mileage” on the sidewall.
• Tires removed from service due to improper repairs.
• Loss of time, inconvenience, loss of use of vehicle,
incidental or consequential damage.

[jerichorick]

Originally Posted by Tireman9

With perfectly dry air the pressure increases about 2% for EACH 10°F increase in temperature. Moist air (from a shop that does not do air compressor maintenance) will grow a bit more maybe 3% or 4% depending.

So 70F > 85 = ~ 3% increase or 3 - 4 psi to say 114

Your operating temperature is probably another 20° since you are at max load for 114 + 3% = 117 plus 117 + 3% = 121psi

My suggestion is to get rid of some of the bowling balls in the collection you are carrying around.

No fair peeking in my basement.

Yes, we do have to trim down. But, my point is what you have calculated. My cold pressure is 110psi from the factory. My max psi on the tire is 110 also. again. You just told me that my tires can reach 121psi without a second thought. Am I not in risk of a failure not from load but from design conflicts? If my load was at GVWR what would I gain? My tires are still running high psi.

I just spent some time reading through the Michelin Load & Inflation Table. After reading it over several times it started to make sense. I think I should go to the 295/80 XZA2 Energy. I hope the FMCA discount works for these. I see that I can reduce my front tire pressure to about 95psi with the load I have at the moment. I think I have room for them on the duels also. I just don't want to incur that expense this year.

Is my tire thinking logical in your opinion? (Bowling balls included.)

Thanks for your help.

Rick Y

[Tireman9]

Originally Posted by jerichorick

No fair peeking in my basement.

Yes, we do have to trim down. But, my point is what you have calculated. My cold pressure is 110psi from the factory. My max psi on the tire is 110 also. again. You just told me that my tires can reach 121psi without a second thought. Am I not in risk of a failure not from load but from design conflicts? If my load was at GVWR what would I gain? My tires are still running high psi.

I just spent some time reading through the Michelin Load & Inflation Table. After reading it over several times it started to make sense. I think I should go to the 295/80 XZA2 Energy. I hope the FMCA discount works for these. I see that I can reduce my front tire pressure to about 95psi with the load I have at the moment. I think I have room for them on the duels also. I just don't want to incur that expense this year.

Is my tire thinking logical in your opinion? (Bowling balls included.)

Thanks for your help.

Rick Y

1. Placard inflation
The RV assembler has to indicate the inflation pressure that will yield the load capacity that meets or exceeds the axle GAWR. So if they select the smallest (lowest cost) tire that allows them to do that that is what most RV companies do.

2. Max vs Min
If your Cold Inflation Pressure is 110 then I would not worry about a hot inflation pressure of 120. To me this is a result of your load being high which increases tire flex which generates heat which raises pressure. You aren't going to fail the tire simply due to this pressure. Tires are designed to handle being warm and having higher than CIP.

3. Increasing size & load capacity
I like the idea of having some "Reserve Load" that means having more tire capacity at the CIP than your actual load is. CIP should be based on measured MAX tire load on any one tire on an axle PLUS 10% increase of pressure. Going up in size and/or Load Range will only give you more load capacity if you also increase the pressure.

4 Michelin tables. Sometime they give slightly different numbers than other tire companies. If you have Michelin tires use their tables. if you have Bridgestones use the Bridgestone tables etc. Also Michelin assumes (incorrectly IMO) that everyone's axles are perfectly balanced side to side as they publish tables based on axle load not the higher of the tires on an axle.

5. I cover inflation pressure, selecting tire size, load range and heat numerous times on my blog, so you will need to read the posts yourself if you want the details. I can't re-post all the info here as it would take too much space and when I did that on another RV blog the Admin banned me for posting too much tire information.

[jerichorick]

Originally Posted by Tireman9

1. Placard inflation
The RV assembler has to indicate the inflation pressure that will yield the load capacity that meets or exceeds the axle GAWR. So if they select the smallest (lowest cost) tire that allows them to do that that is what most RV companies do.

2. Max vs Min
If your Cold Inflation Pressure is 110 then I would not worry about a hot inflation pressure of 120. To me this is a result of your load being high which increases tire flex which generates heat which raises pressure. You aren't going to fail the tire simply due to this pressure. Tires are designed to handle being warm and having higher than CIP.

3. Increasing size & load capacity
I like the idea of having some "Reserve Load" that means having more tire capacity at the CIP than your actual load is. CIP should be based on measured MAX tire load on any one tire on an axle PLUS 10% increase of pressure. Going up in size and/or Load Range will only give you more load capacity if you also increase the pressure.

4 Michelin tables. Sometime they give slightly different numbers than other tire companies. If you have Michelin tires use their tables. if you have Bridgestones use the Bridgestone tables etc. Also Michelin assumes (incorrectly IMO) that everyone's axles are perfectly balanced side to side as they publish tables based on axle load not the higher of the tires on an axle.

5. I cover inflation pressure, selecting tire size, load range and heat numerous times on my blog, so you will need to read the posts yourself if you want the details. I can't re-post all the info here as it would take too much space and when I did that on another RV blog the Admin banned me for posting too much tire information.

Thanks. You just verified all of my thinking. I am with you in my basic understanding.

Just a thought. If I select a tire that is handling my load at 100psi and the max load for the tire is at 120psi, it would seem that the tire is not working as hard and it is generating less heat. If the hot psi does go to 120 the tire is still not at design stress limits. This all sounds good but is this reality?

Rick Y

[CJ7ole]

Watching a science type (or maybe a what-was-I-thinking type) show on TV last week and they had to inflate a tire to over 500 psi before it blew. I was shocked. I was expecting it to go at about 150 psi.

[firedoc]

Wasn't a cracked Michelin!😜

[jstdreamin]

Hey Tireman,

I store my coach on a concrete pad. Should I worry about putting a barrier between tires and concrete? If so, what do you recommend?

[Mr_D]

Originally Posted by jerichorick

Your correct. This is what the coach came with.

What I have been seeing in the manufactures specs is that not all tires are alike. The model of the tire is just as important as the size and load rating. I feel it is a good idea to use tires that are commonly available, are the same for all wheels for rotation, and meet the needs of the coach. That is why all of your suggestions are great but, at the same time, must be challenged with reason and education. The tire that survives the tests indicated are the ones to go with. I have no idea if the tires I have indicated are even available. So, options are still open.

I've been RV'ing since 1957, have NEVER rotated the tires on any RV I've ever had. Our rig has two tire sizes, 365/70's on the front and tag and 315/80's on the drive axle. Came from the factory that way.

[Ramzfan]

I have to chime in on this. I had a 1988 Itasca Windcruiser that I purchased new. It had Michelin tires on it. I stored it outside in very hot climates (San Bernardino, CA, Las Vegas, NV) I drove on those tires for fourteen years until I traded the 'ol coach in for another. Never had a blowout. I consider myself very lucky and would never do that again, but it shows what you can do if you're willing to take a chance.

[Ramzfan]

I have never worried about weighing all the corners of my coach, or even the entire coach for that matter. It is what it is, in my opinion. I use common sense...if I have all of the heavy stuff on one side, then I load the rest of the junk on the other side. I have motorhomed for 37 years now and have never had a blowout. If I have to replace my tires every 7 to 10 years with more than half of their tread remaining, what do I care if they're a little over or under loaded? Seems like just another added expense and reason to waste time and effort to me...!

[Tireman9]

Originally Posted by jstdreamin

Hey Tireman,

I store my coach on a concrete pad. Should I worry about putting a barrier between tires and concrete? If so, what do you recommend?

Kind of depends on how wet the concrete floor is. Many floors stay dry so no need for major concern. However a simple sheet of heavy plastic will keep excessive moisture away from your tires.

What we really do not want is tires on wet dirt or sand.

[Magister54]

Less than a year, on our 2006 we had the original tire (DOT2005) and last year a rear interior blown on the highway, no fun... I replaced the 6 of them with Michelin, I was in NH so paid no taxes

[Tireman9]

Originally Posted by Magister54

Less than a year, on our 2006 we had the original tire (DOT2005) and last year a rear interior blown on the highway, no fun... I replaced the 6 of them with Michelin, I was in NH so paid no taxes

Didn't your TPMS give a warning? Do you have the TPMS set to give a warning as soon as the hot tire drops to the CIP? Some TPM have a "Fast Leak" warning that sounds off when you drop from the hot pressure. This could give you a few minutes advance warning and might even save the cost of a tire.