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Old 11-01-2015, 12:04 PM   #61
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I would suggest you use the inflation shown on the tire placard. Others can advise it's exact location but it should be near the driver's left arm.

After you get actual weights then you know the minimum inflation. I would run 10% higher inflation.

Lots of information on my Blog on RV tires.
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Old 11-01-2015, 12:49 PM   #62
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Originally Posted by Tireman9 View Post
I would suggest you use the inflation shown on the tire placard. Others can advise it's exact location but it should be near the driver's left arm.

After you get actual weights then you know the minimum inflation. I would run 10% higher inflation.

Lots of information on my Blog on RV tires.
I know I am probably beating a dead horse by now, but here goes:

With the Berkshire (up to 2014), Forest River put tires/airbags that are right on the edge of the max weight they can support, and that requires max air pressure recommended by Michelin. In some cases, people are over weight even running max air pressure. If you change to different size tires/airbags then you can carry more weight (up to the axle's limit).

In some cases (like mine) the tire placard is incorrect because of the wrong weight or wrong tire size listed.
Example: my tires on my coach are Michelin 255/80R22.5. I have been running 105 in the front based on tire placard. Except my tire placard says the tires are 275/80R22.5. After I had my coach weighed, I need to run 110 which is the max cold psi for the 255 tire to support the weight. (even then I am overweight by 400lbs).

Forest River is changing my tires and airbags to correct this issue.


Bottom line: Different tire manufacturers recommend different pressures for different tire sizes based on weight. There is no "one size fits all". Weigh your coach and look at the tire tables for your exact tire so that you will know what pressure to run. That is the only way to be sure.
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Old 11-01-2015, 01:18 PM   #63
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Quote:
Originally Posted by baddmann View Post
I know I am probably beating a dead horse by now, but here goes:

With the Berkshire (up to 2014), Forest River put tires/airbags that are right on the edge of the max weight they can support, and that requires max air pressure recommended by Michelin. In some cases, people are over weight even running max air pressure. If you change to different size tires/airbags then you can carry more weight (up to the axle's limit).

In some cases (like mine) the tire placard is incorrect because of the wrong weight or wrong tire size listed.
Example: my tires on my coach are Michelin 255/80R22.5. I have been running 105 in the front based on tire placard. Except my tire placard says the tires are 275/80R22.5. After I had my coach weighed, I need to run 110 which is the max cold psi for the 255 tire to support the weight. (even then I am overweight by 400lbs).

Forest River is changing my tires and airbags to correct this issue.

I agree with others in this thread (Phil, Mmnsc, Campin Cajun) because we have researched and discussed this for a while. If don't own a Berkshire, you probably aren't as informed on this issue. That is why we ask what kind of MH you have. It makes a difference on this forum.

Bottom line: Different tire manufacturers recommend different pressures for different tire sizes based on weight. There is no "one size fits all". Weigh your coach and look at the tire tables for your exact tire so that you will know what pressure to run. That is the only way to be sure.

Glad to hear you were able to get FR to correct the situation. Did you report the violation the NHTSA? I would be surprised if there was only one RV made with incorrect placard information. We are talking about violating Federal Safety regulations here.

I don't remember hearing about a recall by FR.
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Old 11-01-2015, 01:26 PM   #64
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There is a thread about the weight issue and Forest River Berkshire group is taking good care of us with the issue. Not every Berkshire model has the weight problem that is why you need to get the coach weighed with full fuel,propane, empty tanks and empty coach except for driver and spouse.
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Old 11-01-2015, 04:09 PM   #65
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Quote:
Originally Posted by baddmann View Post
I know I am probably beating a dead horse by now, but here goes:

With the Berkshire (up to 2014), Forest River put tires/airbags that are right on the edge of the max weight they can support, and that requires max air pressure recommended by Michelin. In some cases, people are over weight even running max air pressure. If you change to different size tires/airbags then you can carry more weight (up to the axle's limit).

In some cases (like mine) the tire placard is incorrect because of the wrong weight or wrong tire size listed.
Example: my tires on my coach are Michelin 255/80R22.5. I have been running 105 in the front based on tire placard. Except my tire placard says the tires are 275/80R22.5. After I had my coach weighed, I need to run 110 which is the max cold psi for the 255 tire to support the weight. (even then I am overweight by 400lbs).

Forest River is changing my tires and airbags to correct this issue.

I agree with others in this thread (Phil, Mmnsc, Campin Cajun) because we have researched and discussed this for a while. If don't own a Berkshire, you probably aren't as informed on this issue. That is why we ask what kind of MH you have. It makes a difference on this forum.

Bottom line: Different tire manufacturers recommend different pressures for different tire sizes based on weight. There is no "one size fits all". Weigh your coach and look at the tire tables for your exact tire so that you will know what pressure to run. That is the only way to be sure.
Bolded the part of my reaction.
In your case you even could have used higher pressure then 110.
This is not the maximum allowed cold pressure of a tire but the pressure at wich the maximum load can be carried up to maximum speed of tire ( yours probably only 75m/h) , without any part of rubber gets that hot that it hardens and damages in next bendings ( this to the calculation of tire-makers).

Then there are 2 things important, one is to keep within the rules and regulations of tire organisations, and second more important is to stay within the rules of nature.

To the rules of nature you can probably use even 130 psi to have enaugh reserve for things like , pressure loss in time, loadshifting on the axle R/L, etc. And the tire can handle that without blowing by to high pressure.
Even the highening up of pressure by rising of temperature in tire the tire can handle.

But not if its already damaged by overheating , by using to low pressure for the weight on tire and speed used.
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Old 11-01-2015, 05:04 PM   #66
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Motorhomes are loaded to GVWR not total GAWR. Here is a quote from a NHTSA Q&A information PDF:

“The FMVSS have requirements for the manufacturer to use proper tires and rims for the gross axle weight rating (GAWR) and the gross vehicle weight rating (GVWR). The manufacturer may determine the GVWR by adding cargo capacity (if any) to the curb weight of the vehicle as manufactured. The wise consumer, before purchase, will determine if the vehicle has sufficient cargo capacity to carry the weight of water, additional equipment (such as televisions, and microwave ovens), and luggage. The manufacturer’s certification label must show the GVWR. The GVWR must not be exceeded by overloading the vehicle. There is little the government can do to assist a consumer who has purchased a vehicle that has insufficient cargo capacity for its intended use.”
.
Because of the way vehicle manufacturers set GAWR and select tire fitments for them the recommended cold tire pressures should always be valid unless the vehicle is overloaded (total vehicle weight is higher than GVWR) or unbalanced (cargo management) causing a wheel position or axle to be overloaded.

Vehicle owner manuals, even generic ones, must provide a section on tire safety ) it’s mandated by NHTSA). What I’ve said above can also be found in your owner’s manual. So what I’m getting at is; Are you managing your tire pressures because of overloading or unbalanced conditions.

http://idn.tweddle.com/forestriver/manual?itemtype=UG&brand=Forest_River_RV&model=Cla ss_A_Diesel&language=EN_US&year=2015&market=US&idn _session=hdsifknu23oeuqfrrcme282jn4
http://idn.tweddle.com/forestriver/manual?itemtype=UG&brand=Forest_River_RV&model=Cla ss_A_Diesel&language=EN_US&year=2015&market=US&idn _session=hdsifknu23oeuqfrrcme282jn4
 
The following regulation excerpts apply.

“The weight value for load carrying capacity on the RV load carrying capacity labels must be displayed to the nearest kilogram with conversion to the nearest pound and must be such that the vehicle's weight does not exceed its GVWR when loaded with the stated load carrying capacity. The UVW and the GVWR used to determine the RV's load carrying capacity must reflect the weights and design of the motor home as configured for delivery to the dealer/service facility. If applicable, the weight of full propane tanks must be included in the RV's UVW and the weight of on-board potable water must be treated as cargo.”
 
If weight exceeding 45.4 kg (100 pounds) is added to a motor home between final vehicle certification and first retail sale of the vehicle, the load carrying capacity values on the RV load carrying capacity labels must be corrected.

Bottom line: Tire inflation pressures can be managed as long as all safety precautions are observed. First you must have tires that provide some reserves - by inflation - above the recommended inflation pressures. Do not add inflation pressures that will exceed the maximum load capacity of the tires. Look on the individual tire’s sidewall for maximum load capacity values.

Never use less inflation pressures than what has been recommended on the vehicle’s certification label.
When plus sizing up from your OE tires you may need to determine what the recommended inflation pressures are for the replacement tires. If they require adjustments auxiliary tire placards are allowed and can be hand written and placed adjacent to the certification label. You should also make notations in the vehicle owner manual. An experienced and savvy tire installer may automatically do that for you.

Tire manufacturers are notorious for not providing 100% of the information needed to make sound decisions about their product and it’s fitment regulations and standards.

The procedure to support the load carried by inflation needs scrutinization. A loss of a single psi of tire inflation pressure causes a loss of 1.6% of it’s load capacity.


I just knew nobody would write NHTSA.
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Old 11-01-2015, 05:23 PM   #67
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Quote:
Originally Posted by Airdale View Post
Motorhomes are loaded to GVWR not total GAWR. Here is a quote from a NHTSA Q&A information PDF:

“The FMVSS have requirements for the manufacturer to use proper tires and rims for the gross axle weight rating (GAWR) and the gross vehicle weight rating (GVWR). The manufacturer may determine the GVWR by adding cargo capacity (if any) to the curb weight of the vehicle as manufactured. The wise consumer, before purchase, will determine if the vehicle has sufficient cargo capacity to carry the weight of water, additional equipment (such as televisions, and microwave ovens), and luggage. The manufacturer’s certification label must show the GVWR. The GVWR must not be exceeded by overloading the vehicle. There is little the government can do to assist a consumer who has purchased a vehicle that has insufficient cargo capacity for its intended use.”
.
Because of the way vehicle manufacturers set GAWR and select tire fitments for them the recommended cold tire pressures should always be valid unless the vehicle is overloaded (total vehicle weight is higher than GVWR) or unbalanced (cargo management) causing a wheel position or axle to be overloaded.

Vehicle owner manuals, even generic ones, must provide a section on tire safety ) it’s mandated by NHTSA). What I’ve said above can also be found in your owner’s manual. So what I’m getting at is; Are you managing your tire pressures because of overloading or unbalanced conditions.

http://idn.tweddle.com/forestriver/manual?itemtype=UG&brand=Forest_River_RV&model=Cla ss_A_Diesel&language=EN_US&year=2015&market=US&idn _session=hdsifknu23oeuqfrrcme282jn4
http://idn.tweddle.com/forestriver/manual?itemtype=UG&brand=Forest_River_RV&model=Cla ss_A_Diesel&language=EN_US&year=2015&market=US&idn _session=hdsifknu23oeuqfrrcme282jn4
 
The following regulation excerpts apply.

“The weight value for load carrying capacity on the RV load carrying capacity labels must be displayed to the nearest kilogram with conversion to the nearest pound and must be such that the vehicle's weight does not exceed its GVWR when loaded with the stated load carrying capacity. The UVW and the GVWR used to determine the RV's load carrying capacity must reflect the weights and design of the motor home as configured for delivery to the dealer/service facility. If applicable, the weight of full propane tanks must be included in the RV's UVW and the weight of on-board potable water must be treated as cargo.”
 
If weight exceeding 45.4 kg (100 pounds) is added to a motor home between final vehicle certification and first retail sale of the vehicle, the load carrying capacity values on the RV load carrying capacity labels must be corrected.

Bottom line: Tire inflation pressures can be managed as long as all safety precautions are observed. First you must have tires that provide some reserves - by inflation - above the recommended inflation pressures. Do not add inflation pressures that will exceed the maximum load capacity of the tires. Look on the individual tire’s sidewall for maximum load capacity values.

Never use less inflation pressures than what has been recommended on the vehicle’s certification label.
When plus sizing up from your OE tires you may need to determine what the recommended inflation pressures are for the replacement tires. If they require adjustments auxiliary tire placards are allowed and can be hand written and placed adjacent to the certification label. You should also make notations in the vehicle owner manual. An experienced and savvy tire installer may automatically do that for you.

Tire manufacturers are notorious for not providing 100% of the information needed to make sound decisions about their product and it’s fitment regulations and standards.

The procedure to support the load carried by inflation needs scrutinization. A loss of a single psi of tire inflation pressure causes a loss of 1.6% of it’s load capacity.


I just knew nobody would write NHTSA.
I'm sitting scratching my head I have no idea what you just said. All I know is my coach was over weight before the upgrade before any thing was in the coach and it is being taken care of. I know what my tires can carry and the weight of my coach. The Berkshire guys have a handle on what is happening . By the way I haven't heard of the Berks blowing tires like the all the trailer posts there are blaming Chinese tires I think they need some help there.
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Old 11-01-2015, 05:37 PM   #68
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Wow I enjoyed reading this stream of knowledge. I just came back from Camp FL. I say run your tires closer to the max. Why you ask? I CAT scaled my 2015 Berkshire 40BH then had the FL SS scale all 4 wheels. So I hope u get a kick out of this. The Cat scales showed 1000 lbs more than the FL SS, ND even more interesting both front wheels were identical and so were both rear wheels. So we know that's not possible! They agreed to scale the next morning, keep in mind I am parked at the FL SS. The 1st quest was did I take on 500lbs of H20? And no I didn't. So they scaled it 2 more times and came up with 2 new scale sheets which didn't match either but still never close to the Cat scales. If interested I will post all of the sheets.
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Old 11-01-2015, 05:40 PM   #69
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ND= and and SS = service center
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Old 11-01-2015, 06:31 PM   #70
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I have seen several 15's with Michelins. Other then a individual issue or two I always thought they were a good tire. Are you having problems
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