Axle Overloading - Lack of Standards

[RMacKillop]

Hi.

Until 2008 there was a simple definition of Cargo carrying capacity, CCC. It was the GVWR minus the weight of the coach with full water, full fuel and 4 passengers at 154 lbs each.

In their wisdom (and perhaps pressure by the RV industry), NHTSA changed the system to make the cargo capacity seem greater. It now is the GVWR minus the coach with full fuel. The placards indicate that the owner must allow for the weight of occupants and water.

One of the problems here is that the weight of the water affects the front and rear axle differently and most owners don't realize that the weight of the passengers is almost entirely on the front axle (in theory, 4 X 154= 616 lbs).

Manufacturers are obliged to placard the coaches this way and now any additional changes done by the dealer must be placed on that placard.

An example of the problem and risk is in the August 2010 FMC magazine feature article on the 2010 Itasca Ellipse 42AD. The front axle as tested was 13,520 with only full fuel and water The axle rating is 14,320. The carrying capacity of that axle is only 800 lbs while the coach has a capacity of almost 10,000 lbs.

If 4 small adults ride in the motorhome, the front axle reserve capacity is now under 150 to 200 lbs. The owner will be overweight by filling the fridge!

As for the tires, 275/80R 22.5. - 120 psi must be maintained to carry the load of 14,320lbs. At 115 psi, they are overloaded with just the 4 passengers. Michelin states that there should be a reserve.

The above is with the premise that the right and left front wheels have exactly the same loading. Unlikely.

All owners should weigh individual wheels in the motorhome. http://www.rvsafety.com/

FMCA should standardize their reports. There should be a watchdog group taking some responsibility. NHTSA? RIVA?

I think that this motorhome should not be offered for sale as is.

Ross

[wolfe10]

From the article:

AS-TESTED WEIGHT

(weighed with full water and fuel)

front axle — 13,520 pounds;

rear drive axle — 10,420 pounds;

tag axle — 10,760 pounds;

total — 34,700 pounds

I would suggest that the tag axle is WAY mis-adjusted, causing the problem.

Remember, taking weight on the tag removes weight from the drive axle AND ADDS WEIGHT TO THE FRONT AXLE.

No way should the tag axle be carrying more (or even close to the same) weight as the drive axle.

Yes, this should have been checked and adjusted at the Winnebago factory.

Brett

[RMacKillop]

True, but moving 2000 lbs from the tag to the drive may lighten the steer by 300 lbs. Not enough to be reasonable. Fridge and pantry location - probably 80 % front axle load.

Overweight tires is simply unsafe. These tires would be overloaded at 115 psi. and keeping them at exactly 120 is almost impossible. Tire pressure monitors don't have that accuracy.

The point remains - why manufacture it like that? Honest disclosure is usually not the case when a sale is possible.

[wolfe10]

First, I am in total agreement with you that weight capacities need to be easily understood by consumers and "adequate for their intended purpose". And I have said this for many, many years.

But, I don't think it is right to make a judgment on this particular coach/manufacturer based on the weights posted in the article. We all KNOW that either the numbers are incorrect or there is an easily correctable issue with the test coach.

I am talking about moving well more than 2000 pounds from tag to drive axle. Most 30,000 pound drive/tag axles have a 20,000 pound drive axle and 10,000 pound tag axle. With the article listing tag axle actual weight AS MORE THAN the drive axle.... clearly something is amiss.

Let's all wait for a response from Winnebago or a post with more realistic front/drive/tag axle distributions. THEN we can compliment or condemn.

Brett

[kharms@winnebagoind.com]

First, I am in total agreement with you that weight capacities need to be easily understood by consumers and "adequate for their intended purpose". And I have said this for many, many years.

But, I don't think it is right to make a judgment on this particular coach/manufacturer based on the weights posted in the article. We all KNOW that either the numbers are incorrect or there is an easily correctable issue with the test coach.

I am talking about moving well more than 2000 pounds from tag to drive axle. Most 30,000 pound drive/tag axles have a 20,000 pound drive axle and 10,000 pound tag axle. With the article listing tag axle actual weight AS MORE THAN the drive axle.... clearly something is amiss.

Let's all wait for a response from Winnebago or a post with more realistic front/drive/tag axle distributions. THEN we can compliment or condemn.

Brett

Brett,

Thank you for bringing this to our attention. We are working on resolving the issue and should have a reply to you on Friday. Thanks for your patience.

Winnebago Industries

[RMacKillop]

It is great that Winnebago has responded to the query from FMCA.

Obviously, it is important to show the weights and safety features with accuracy and perhaps this exercise will help.

Unfortunately the buyer usually does not interpret the weights properly, (nor do they get even occasional corner weights of their vehicle) The potential buyer puts far too much faith in the manufacturer.

I believe that most owners of a vehicle with these adjusted weights will often travel with one front wheel dangerously overweight/underinflated.

With the Drive :tag ratio adjusted to a common 60:40, the front axle is 13,344 (180 lbs less then tested). Add 4 light passengers at 154 lbs adds 510 lbs to the front axle. (2 in front of the steer axle and 2 at 60% on the front axle). The front axle now is loaded at 13,854. leaving a reserve of 466. The tires must be maxed to 120 psi even for this. The pantry weight is entirely on the front axle and the large fridge contents will be 80% on the front. The front bays aren't much use. It can be managed IF the side to side balance is perfect (unlikely as 5 % variance is often "allowed") and the tires are never below 120 psi.

Why would a knowledgeable buyer bother risking this? Why did not the manufacturer design in SOME margin of safety for the axle and tires ?

Ross

[wolfe10]

Ross,

I have to respectfully disagree with you on the adequacy of this particular coach's weight carrying capacity FOR MOST BUYERS.

Based on the Winnebago/Freightliners numbers (with full fuel and water) the reserves are:

Front: 976 pound reserve

Drive: 7,272 pound reserve

Tag: 1,135 pound reserve

The vast majority of coaches on the road today have less.

I do, however, strongly agree with your main point: All buyers should verify that the reserve capacity of any coaches on their "short list" meets their needs. And different buyers can have very different needs-- i.e. some may just weekend, while others looking at the same coach may full time and may collect rocks for a hobby.

Brett

[RMacKillop]

Hi Brett,

Your suggestion of reserve is exclusive of passengers.

This is part of the problem-- There is no ACCEPTED standard.

The definition of CCC in the past has been GVWR minus (full fuel, +propane, +potable water+ scwr ) = CCC

scwr sleeping capacity weight rating- usually considered at 4 -- 154 lbs each)

In this case the cargo that can be carried on the front axle is 466. (That is 233 per side- If the driver is 204 lbs, not 154, then one side has the capacity of 183 lbs-- a little side to side discrepancy is overweight-- No cargo) The tires must be exactly 120 psi. There is no reserve capacity. Grey and black must always be empty.

The new OCCC standard(NHTSA) excludes the water and passengers and includes them in the cargo capacity.

If you use this system the cargo (including water and passengers) is well over 1000 lbs. The problem in this sytem is that a potential owner has no idea as to the load split of the water.

For Winnebago to weigh with partial fuel is of no value to a prospective buyer for the same reason and that it follows NO standard

[mikev]

Hi everyone, this a timely topic to me, I have been running with tire pressures too high -105psi approximately 10psi over the required amount of 90+5 reserve now that I have accurate weights to deal with. We purchased the coach last year and I decided to run at higher pressure given the GVWR of my coach and using the Goodyear chart. Until yesterday I was unable to find a location to weigh my coach at all four corners individually-just total axle weights and as I read here in a forum the difference side to side on an axle can be substantial.

Unfortunately the coach rally's nearest to us were just out of our time or distance requirements this last year.

I finally found and rented a wheel pad scale and decided to do it myself. I stripped my coach to match the original UVW provided by Monaco and found my coach was almost 1500 pounds above the listed "exemplar" weight. The proviso by Monaco is "note #1" "The UVW and CCC have been determined by weighing an exemplar motorhome with some but not all optional equipment , please contact the manufacturer for the actual weight of each option".... Frankly the data sheets they provided are very impressive looking but in practice almost useless to the specific customer unless they would have given corner weights of his/her coach.

I ensured the ground was as level as possible laterally and fore/aft and took all weights values twice.

Next I added full fresh water and weighed it again. This gave me a good baseline to see how the 800lbs would affect the front and rear axles. Lastly I fully loaded the coach and hooked up the toad-we are going away this weekend anyway- stuck my adult son in the driver's seat and my wife in her seat, adjusted for his weight difference and mine, no I'm not going to say how much it was, just that it was needed...After this I got our regular traveling weight at each corner. There was approx 200 lbs difference across the front axle and 350 across the back. Enough to bump up the tire pressures by 5psi. Now I can drop the tire pressure to where it should be and feel good about running down the road. I also now know that I must be careful to load more toward the front of my coach when my wife goes on a shopping spree or I find that must have new tool. My rear axle is only a few hundred lbs short of the maximum but I have plenty up front.

In looking for a scale I called three of the arguably biggest RV centres in my region and found they do not have scales and they sounded like they thought I was nuts for asking. Their response to how do they advise their customers on tire pressure was not worth repeating.. Between this lack in the RV sales centres(at least in my area) and a major manufacturer like Monaco's not giving actual corner weights when they sell you a $100,000+ motorhome, no wonder there are so many articles on this and other forums about tires etc.

Just a thought...should not all manufacturers be obliged to provide actual wheel position weights of the UVW of every coach that rolls off the assembly line? We are not talking about a big time or expense issue here. Then the customer could make real informed decisions about the pressure of their tires and the loading of their coaches. I am limited in my knowledge of all the manufacturer's practices, so my apologies if Monaco and other manufacturers are already providing the corner weights of every coach.

Out of all this I know that I will not buy another coach without it being weighed properly so I can evaluate whether it will be satisfactory to my needs. Not only total CCC but whether I can actually load up that big cargo area without going over on an individual axle's limit. It's not much use having lots of CCC and all this space to carry stuff if the balance is out to lunch. Also I want to know whether the manufacturer has selected tires that give plenty of reserve capacity.

It's truly great that the FMCA have these forums and valuable folks like Brett or there would be a lot more of us in the dark.

My thanks to Brett and Ross for this exchange, we all learn more this way.

p.s. Has Winnebago gotten back to you Brett? I look forward to hearing what came of these numbers that Ross brought to all our attention. I don't have a tag axle so the adjustment issue has my curiosity going..

Cheers

[wolfe10]

Mike,

Excellent-- good description and reasonable conclusions.

The one thing I didn't see in your analysis was to start by verifying ride height before verifying weights. If a ride height valve is out even a half an inch, it can shift quite a lot of weight side to side.

Concerning the original post/article:

The weights I posted above (Aug 9 2010, 06:37 PM) show the weights that both Freightliner and Winnebago got for the same coach-- and those numbers do make more sense than those published in the article.

That doesn't mean I wouldn't rather see the percent of reserve capacity on each axle even closer.

Brett

[mikev]

Brett, sorry about that, earlier this spring I replaced the trailing arms on my coach and installed the ride enhancement kit as well, both kits from Source Engineering. At that time and once since then I checked and adjusted the ride heights. It slipped my mind in the discussion. By the way the replacement parts were excellent as well as the improvement in the coach's ride and handling.

I think the most important lesson in all this discussion of weights, ride height, balance etc is that buying a motorhome is easy, but to really own one requires a fair effort to learn all the systems, practices and responsibilities to keep such a complex piece of machinery safely on the road. We in the helicopter maintenance business say helicopters are nothing more that a collection of parts flying in formation. I've come to realize over the last year that motorhomes are the wheeled equivalent of that saying...Coach manufacturers assemble a bunch of parts in a collection and then it seems we the owners have to find a way to keep them all together.

Cheers

[RMacKillop]

Hi,

I think that the deletion of Winnebago's reply Aug 9th is unfortunate as it breaks the discussion and makes my relies Aug 10 appear disjointed. The weights that Winnebago gave confirmed the 2000 lb weight shift effect.

Also, the editing of the heading confirms the point suggested by the original heading.

Manufacturers are now obliged to each unit and dealers must show changes if they change the load with options (before the sale)

Ross MacKillop

2006 Blue Bird 450 LXi

[wolfe10]

Ross,

I agree, it is unfortunate that the Winnebago post was deleted. You can see the weights they posted that both they and Freightliner got for that coach in my post 8.9 7:37 PM.

I just got off the phone with the system administrator at FMCA. If you recall, the day the whole FMCA website went down for a week, funny things were happening. He was reviewing that post (as he and I do all posts) and it appeared that they had posted the same information twice. He tried to delete one copy and both disappeared.

When the FMCA Website came back up, he contacted Winnebago and asked them to re-post it.

As far as the title, remember, many use the search engine to find topics of interest. "Axle Overloading - Lack of Standards, Cargo Carrying Capacity can be misleading" does convey the sense of the thread and allows the search engine to come up with the discussion.

Brett

[RMacKillop]

Hi,

I do not see a post from you dated Aug 9th. Nor do I see the weights from Winnebago.

Ross

[wolfe10]

Hi,

I do not see a post from you dated Aug 9th. Nor do I see the weights from Winnebago.

Ross

Ross,

That is REALLY weird.

Aug 9 2010, 07:37 PM is still showing as a post for me. I will cut and pasted it here:

Posted Aug 9 2010, 07:37 PM

Ross,

I have to respectfully disagree with you on the adequacy of this particular coach's weight carrying capacity FOR MOST BUYERS.

Based on the Winnebago/Freightliners numbers (with full fuel and water) the reserves are:

Front: 976 pound reserve

Drive: 7,272 pound reserve

Tag: 1,135 pound reserve

The vast majority of coaches on the road today have less.

I do, however, strongly agree with your main point: All buyers should verify that the reserve capacity of any coaches on their "short list" meets their needs. And different buyers can have very different needs-- i.e. some may just weekend, while others looking at the same coach may full time and may collect rocks for a hobby.

[RMacKillop]

OK sorry, that shows as Aug 10,2010 1:37 AM on our screens.

Also , that does not show Winnebagos actual weight numbers but "Based on the Winnebago/Frieghtliner numbers" are your reserve numbers. These "reserve capacities" that you suggest show the problem.

Lack of Standards--

To cut and paste the earlier post:

Hi Brett,

Your suggestion of reserve is exclusive of passengers.

This is part of the problem-- There is no ACCEPTED standard.

The definition of CCC in the past has been GVWR minus (full fuel, +propane, +potable water+ scwr ) = CCC

scwr sleeping capacity weight rating- usually considered at 4 -- 154 lbs each)

In this case the cargo that can be carried on the front axle is 466. (That is 233 per side- If the driver is 204 lbs, not 154, then one side has the capacity of 183 lbs-- a little side to side discrepancy is overweight-- No cargo) The tires must be exactly 120 psi. There is no reserve capacity. Michelin suggests increasing the air pressure to allow a 500 lb reserve. This is not possible here. Grey and black must always be empty.

The new OCCC standard(NHTSA) excludes the water and passengers and includes them in the cargo capacity.

If you use this system the cargo (including water and passengers) is well over 1000 lbs. The problem in this sytem is that a potential owner has no idea as to the load split of the water.

For Winnebago to weigh with partial fuel is of no value to a prospective buyer for the same reason and that it follows NO standard

[tmoning]

Winnebago posted the following reply in early August, but it was unintentionally removed from this thread. With Winnebago's permission it is posted again here ...

When we read your comments and the "As-Tested Weight" information from the Itasca Ellipse 42AD test article in Family Motor Coaching, we were concerned as the data did not reflect our design parameters or the test data for that model.

To follow up, we had the very same coach used in the test drive taken to Freightliner Custom Chassis facilities in Portland, Oregon, for weight analyses. We also had our own Test Lab facilities analyze and verify the specific weight measurements for this model.

In both cases we found the drive and tag axle weights to be considerably different than the information posted in the article. Our Test Lab data based on full fuel and water shows a tag axle weight of 8,865 lbs., a drive axle weight of 12,728 lbs. and front axle weight of 13,344 lbs.

Drive axle -- Winnebago test lab 12,728 lbs. | FMC magazine article 10,420 lbs. | GAVWR 20, 000 lbs.

Tag axle -- Winnebago test lab 8,865 lbs. | FMC magazine article 10,760 lbs. | GAVWR 10,000 lbs.

Front axle -- Winnebago test lab 13,344 lbs. | FMC magazine article 13,520 lbs. | GAVWR 14,320 lbs.

Total -- Winnebago test lab 34,937 lbs. | FMC magazine article 34,700 pounds |GAVWR 44,320 lbs.

We also conducted the same exercise with 1/2 tank of fuel and 2/3 water onboard to further verify axle load through a range of scenarios. These weights show the tag axle at 8,825 lbs., the drive axle 12,764 lbs. and the front axle at 12,689 lbs. Both the Freightliner and Winnebago Industries Test Lab measurements were consistent.

Based on these findings, we believe that there was a discrepancy with the original weight measurements taken for the article.

We will share this same data with Family Motor Coaching magazine so they can print a clarification in an upcoming issue.

Thank you.

Winnebago Industries, Inc.

[wolfe10]

OK sorry, that shows as Aug 10,2010 1:37 AM on our screens.

Ross,

No problem. The time difference is explained by the time zone I am in vs the one you are in. As an example, it is currently 4:00 PM on 8/23 where we are in Texas (CDT).

Obviously, you are WAY east of us!

Brett

[tireman9]

Might this thread point out the need for FMCA coach reviews to include actual corner weights? We need to do as much as possible to educate owners of the importance and Safety improvement if they know their real loads.

We might also see some improvements from manufacturers if they see their real weights posted where MFG A has good balance side to side as well as appropriate reserve spread across all axles when MFG B doesn't.

[RMacKillop]

Back to " LACK OF STANDARDS"

FMCA October magazine has an interesting article on the Born Free 22 foot Class C. Aside from there being an addition error with Wet weight as tested, it shows the the lack of standards for weighing RVs. I believe that this is dangerous.

As the first post in this topic:

"Until 2008 there was a simple definition of Cargo carrying capacity, CCC. It was the GVWR minus the weight of the coach with full water, full fuel and 4 passengers at 154 lbs each.

In their wisdom (and perhaps pressure by the RV industry), NHTSA changed the system to make the cargo capacity seem greater. It now is the GVWR minus the coach with full fuel. The placards indicate that the owner must allow for the weight of occupants and water.

One of the problems here is that the weight of the water affects the front and rear axle differently and most owners don't realize that the weight of the passengers is almost entirely on the front axle (in theory, 4 X 154= 616 lbs).

In this article OCCC is not correct, as the weight of the water is not included in this number.

OCCC here would be 12500 - 10520 + 180 (water weight) = 2260, not 2556. Not a big deal here, but shows the lack of standards.

CCC would be 12500 - 10520 -616 = 1464

Even for this Class C, there is a large difference between CCC and OCCC. In this case, there appears to be no concern as there are only 24 gallons of water and the GAWR's seem capable.

I edited this post as Brett corrected me that GVWR is sometimes less then the sum of the GAWR ... 12500 is the GVWR, which is less then the GAWR.

[wolfe10]

Simply stated, OCCC (Occupant & Cargo Carrying Capacity), the industry-wide standard mandated by the Federal Government which went into effect 6/2/08 equals:

GVWR (Gross Vehicle Weight Rating) -- how much the coach can weigh totally loaded/how much can "sit on the tires."

Minus UVW (Unloaded Vehicle Weight)-- the weight of the coach WITH full fuel and propane, but NO water, people, personal gear, dealer added items, etc.

________________________________________________________________________________

As you add water, personal gear, people, tongue weight of any trailer, etc you "use up" OCCC.

And your added "stuff" can still be within the OCCC (i.e. under GVWR) and still have one axle overloaded/one axle well underloaded.

Bottom line is you need to weight the coach when you have it loaded as you go down the road. Two reasons-- to make sure you are not overloaded AND to allow you to choose the correct tire pressure per your tire manufacturer's inflation chart.

Brett

[RMacKillop]

Hi,

Tireman posted the following earlier in the thread. It is really to the point. FMCA is the only consumer group that can have some impact on the manufacturers.

Posting actual weights in the magazine articles is essential. In spite of, or in addition to, the new OCCC standard, the INDIVIDUAL axle loading effects of full water and 4 people should be noted. Omitting all reference to weights as in the recent Astoria article in the magazine is not of service to the FMCA members.

Now that Blue Bird has been found guilty of fraud, other manufacturers may take notice. FMCA can join in and educate owners.

Ross

from a press release:

.............. On November 18, 2010, an Ottawa County Michigan jury rendered a verdict that Blue Bird Corporation committed fraud, among other things, in that it knowingly manufactured 57 overweight and dangerous motor homes and for three years, between 2004-2007, sold them to unsuspecting customers

Blue Bird manufactured and sold these coaches, designated Blue Bird “Wanderlodge M450LXiâ€, at prices starting in the $700,000s and reaching over one million dollars .

The jury verdict stated that Blue Bird made the fraudulent statements with the intent that the statements be relied upon by it customer and that Blue Bird intentionally created a false impression about its product intending that its customer would rely upon it.....................................

post from "tireman"

Might this thread point out the need for FMCA coach reviews to include actual corner weights? We need to do as much as possible to educate owners of the importance and Safety improvement if they know their real loads.

We might also see some improvements from manufacturers if they see their real weights posted where MFG A has good balance side to side as well as appropriate reserve spread across all axles when MFG B doesn't.

--------------------

Retired Tire Design and Quality Engineer (40 years experience). Retired Professional race car driver. Retired Police Driving Instructor. Give seminars at FMCA and other Rallys on Tires and also on Genealogy.