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Old 04-25-2013, 01:09 PM   #41
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I have been following this thread for a while and recently weighed my 2013 390BH. It was weighed fully loaded with full diesel and propane, 1/4 in the holding tanks, but without the rest of my family. The rest of the family would likely add another 400lbs. My yellow door sticker says the dry weight is approx. 25,500 and that I have approx. 1500lbs carrying capacity (roughly those numbers, but I'm not near the coach).

The CAT scale said I was exactly on weight for the rear axle at 17,500 and somewhat over on the front at 10,800. I have added cargo slides, a freezer and a heavy grill ion the basement, but was surprised nonetheless to be over the limit. Once the family gets on board with some extra grocery, clothes, etc, I'm going to be around 1000lbs over GVWR. Sadly, I'm not sure what to do about this. I've seen the posts about the mods to the front axle, but sheesh... how can this be? The coach drives beautifully, so that is not a concern, but it definitely is in the back of my mind...
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Old 04-25-2013, 02:00 PM   #42
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Originally Posted by CapuTech View Post
"...My yellow door sticker says the dry weight is approx. ... ...(roughly those numbers, but I'm not near the coach)"
...I'm going to be around 1000lbs over GVWR....

"...The coach drives beautifully, so that is not a concern, but it definitely is in the back of my mind...
I recommend that you go to the coach and get your exact numbers, otherwise you don't know how far over you are. Your GAWR (front & rear) are probably the same as or close to mine, as listed in my previous post in this thread on 4/20, in which case you are nowhere near that much over your FA GAWR.

It probably drives beautifully because it's not that much overloaded. Note that there are overload figures for both the axle (GAWR) and the tire(s) (Michelin tables), both of which are important. My 390RB is loaded about the same as yours, and the front tires are overloaded until I am at a 64% fuel level. I have no front axle (FA GAWR) or total vehicle (GVWR) overload after I reach a 45% fuel level. Please keep in mind that the minor amounts of overload we are talking about are not significant in the scheme of things.

HOWEVER: It's VERY important to get your tires properly inflated. I have the 255/80R22.5 LRG XRV tires, and run 110 psig "cold" at 70F in the front tires, as determined with a digital gauge, or 108 @ 50F "cold" (I have a NIST 2A test stand, and find most digital gauges to conform to 2A standards, and most non-digital gauges to be off quite a bit). I measure on an overcast day shortly after sunrise, as direct sunlight on black tires can send the pressures right up, usually only on one side of the vehicle, and not on the inner tires. I run 94 psig in the rear tires, and at that pressure they are about 0-2 psig overinflated, depending on whether or not I am at the rear GAWR.

I recommend you scroll up and read my 4/20 post. Happy Trails!
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Old 04-25-2013, 02:32 PM   #43
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Originally Posted by NO3putt View Post
...Front tires presure goes up about 11 lbs when hot and rear go up a out 6 lbs. Is that presure increase about normal?
Years ago (we won't say how many) I was a product development engineer for a major manufacturer of polyester and rayon tire filaments. The friction within the tire wall from flexion of the sidewall (once per rotation) is what causes the temperature increase, and if the tire is significantly underinflated, then the grossly elevated temperatures will cause sidewall failure. AT 4000 frames/sec (I know! - old technology) it appears that the failure starts at a point, and travels around the tire in both directions to meet itself. In real time, it appears instantaneous.

Low tire pressures give better impact resistance, and should be used at really low speeds only (e.g. 5 -10 mph along an unpaved, rocky fire trail in a pickup truck).

You actually have to go into the tire manufacturer's tables and try to meet the recommended tire pressures, for the load you are at. Refer to my previous post.
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Old 04-25-2013, 02:57 PM   #44
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Update with Actual Numbers

GVWR:
Front: 10,410
Rear: 17,500
Both: 27,910

CAT SCALES:
Front: 10,840 (430 over GAWR)
Rear: 17,500 (right at limit)
Both: 28,340 (430 over GVWR)

HOW IT WAS LOADED:
  • Full Fuel (100 Gals), Full Propane (~20Gals), 7 Gals DEF
  • Gray and Black Tanks at ~1/4 level
  • Fresh tank at ~1/4 (since I cannot drain it below that without sloping as the drain and pump suction are about an inch from the tank bottom).
  • 2 aluminum full length cargo slides and 2 opposing half length steel slides.
  • 80lb grill and 80lb Dometic Freezer in basement.
  • Everything else we bring along in the basement. I.e., tables, chairs, fishing gear, etc.
  • 48 bottled waters, various dry goods, all pots, pans, dishes etc.
  • My buddy in the coach. Roughly same size as me @ 190lbs.

Effectively it was fully loaded except for my wife and three kids. Together they will add less than 400lbs body weight and maybe 200 in clothing and various stuff they bring along. Then maybe 100 lbs in extra groceries and 300lbs of bikes on the hitch. All told another 1000lbs.

So, FULLY loaded, I'd be around 1400lbs over GVWR! And if I want to put a bit of water in the tank...

That's how we have been traveling for the 4 months we have owned it. As I said, it drives beautifully.

Prior to having it weighed, I was running at 108lbs on all tires. I knew I was too high on the rear, but better too high than too low. I will now ride the front at 110 (max) and the rear at 105. I do use a high end digital truck gauge and have Michelin 255/80R22.5 LRG XRV tires.

Attached is my yellow door sticker with statements of Dry Weight of 25,578lbs and CCC of 1,527lbs. The CCC must account for fuel, propane and DEF since 27,910 - 25,578 - 1,527 = 805.

Thanks to all the posts in this thread. The above is a worst case scenario, but even best case, I'm likely still over a bit. I know there is some contingencies in all the ratings, but it still concerns me. Unfortunately, there is not much I can do about it.
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Old 04-25-2013, 04:47 PM   #45
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Quote:
Originally Posted by CapuTech View Post
Update with Actual Numbers

GVWR:
Front: 10,410
Rear: 17,500
Both: 27,910

CAT SCALES:
Front: 10,840 (430 over GAWR)
Rear: 17,500 (right at limit)
Both: 28,340 (430 over GVWR)

HOW IT WAS LOADED:
[*]Full Fuel (100 Gals), Full Propane (~20Gals), 7 Gals DEF[*]Gray and Black Tanks at ~1/4 level[*]Fresh tank at ~1/4 (since I cannot drain it below that without sloping as the drain and pump suction are about an inch from the tank bottom).[*]2 aluminum full length cargo slides and 2 opposing half length steel slides.[*]80lb grill and 80lb Dometic Freezer in basement.[*]Everything else we bring along in the basement. I.e., tables, chairs, fishing gear, etc.[*]48 bottled waters, various dry goods, all pots, pans, dishes etc.[*]My buddy in the coach. Roughly same size as me @ 190lbs.


Effectively it was fully loaded except for my wife and three kids. Together they will add less than 400lbs body weight and maybe 200 in clothing and various stuff they bring along. Then maybe 100 lbs in extra groceries and 300lbs of bikes on the hitch. All told another 1000lbs.

So, FULLY loaded, I'd be around 1400lbs over GVWR! And if I want to put a bit of water in the tank...

That's how we have been traveling for the 4 months we have owned it. As I said, it drives beautifully.

Prior to having it weighed, I was running at 108lbs on all tires. I knew I was too high on the rear, but better too high than too low. I will now ride the front at 110 (max) and the rear at 105. I do use a high end digital truck gauge and have Michelin 255/80R22.5 LRG XRV tires.

Attached is my yellow door sticker with statements of Dry Weight of 25,578lbs and CCC of 1,527lbs. The CCC must account for fuel, propane and DEF since 27,910 - 25,578 - 1,527 = 805.

Thanks to all the posts in this thread. The above is a worst case scenario, but even best case, I'm likely still over a bit. I know there is some contingencies in all the ratings, but it still concerns me. Unfortunately, there is not much I can do about it.
It looks as though FR gave you cargo as promised on the yellow sticker. Although its not as much as we may want I think it's manageable.
Where I ran into issues with mine was a grossly understated dry weight on the yellow sticker. And the fact that on mine I was at GAW on the steer siting empty.
If at sometime you wanted to bump the GVW it can be done. Best to do it when you need tires as the cost would be less. The thing that can't be changed is the GCVW. I managed that with a lighter TOAD.
Nice write up with good numbers. Thanks for taking the time.
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Old 04-25-2013, 05:12 PM   #46
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Please keep in mind that the minor amounts of overload we are talking about are not significant in the scheme of things.
I've been wondering about that. What do you consider a "minor" amount of weight (in percentage) to be??

As I reported earlier I was 900 lbs over on front and 900 lbs over on rear on a coach that lists my limits as 17500 rear and 10410 front.

By my arithmetic that's about 6.5 percent over in total, approx 5% on the rear and just over 8.6% on the front.

Do the designers of these chassis' even build in a little fudge factor, perhaps?? Obviously if I were grossly overloaded (like 50% or higher) it'd even be VISIBLY noticeable.

My coach drives like a dream. I'd rather NOT have to take it back for the front axle upgrade, even though FR has told me they will pay for it. I'm a western states guy and going to SC is a huge pain in the butt for me.

But I worry about the legal implications if I hurt for even kill someone because I didn't have it taken care of. I also worry about additional wear and tear on the tires/suspension parts causing premature failures.

Opinions, anyone??

Boowho??
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Old 04-27-2013, 01:06 PM   #47
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[QUOTE=CapuTech;359949]Update with Actual Numbers


"I knew I was too high on the rear, but better too high than too low. I will now ride the front at 110 (max) and the rear at 105. I do use a high end digital truck gauge and have Michelin 255/80R22.5 LRG XRV tires."

You have the right idea, and are among the few people whose posts indicate the they are using a digital gauge, and doing the research and the math to get it right. However, you are underestimating the negative effects of being WAY overinflated in the rear. In order of severity, they are as follows:
1.) The tires each have a severely reduced footprint, and in wet road conditions, the rear end traction could be lost (no further elaboration for that one)*
2.) The tires have reduced impact resistance against failure
3.) At 108 psig, I noticed a loud "banging" in the rear every time the rear axle went over even a minor bump (tires were too hard, and the sidewalls were not flexing enough) - refer to no. 2, above
4.) You will experience greater tread wear on the inner portion of the tread, known as a "shot out tread" (you are probably already aware of that)

Having said that, I must confess that I did the exact same thing you are doing, until I got into the Michelin tables, and was aghast that at 95 psi in the rear tires, I would still be slightly overinflated when at the rear axle GAWR. At 105 psi, you are severely overinflated. Even though the rear GAWR is much higher than the front GAWR, you will note that for the rear tires you should be using the data in the inflation tables located in the "double" row, not the "single" row - you've got duallys back there.

Good luck, and happy motoring. The Berkshire is one well-thought out, beautiful unit.

* the highest risk for this scenario is when you are flat towing a car behind you, in the rain, and are braking while going around a corner and using the exhaust brake all at once (Freightliner cautions against using the EB in wet conditions)
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Old 04-27-2013, 01:33 PM   #48
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Originally Posted by boowho View Post
I've been wondering about that. What do you consider a "minor" amount of weight (in percentage) to be??

As I reported earlier I was 900 lbs over on front and 900 lbs over on rear on a coach that lists my limits as 17500 rear and 10410 front.

By my arithmetic that's about 6.5 percent over in total, approx 5% on the rear and just over 8.6% on the front.

Do the designers of these chassis' even build in a little fudge factor, perhaps?? Obviously if I were grossly overloaded (like 50% or higher) it'd even be VISIBLY noticeable.

My coach drives like a dream. I'd rather NOT have to take it back for the front axle upgrade, even though FR has told me they will pay for it. I'm a western states guy and going to SC is a huge pain in the butt for me.

But I worry about the legal implications if I hurt for even kill someone because I didn't have it taken care of. I also worry about additional wear and tear on the tires/suspension parts causing premature failures.

Opinions, anyone??

Boowho??
No offense, but in our litigious society, you won't get anyone to throw a number out there, but for most stress applications, design is often of the order of magnitude of 100% over rating (2X). (now there is a broad statement) That is not to say that negative handling characteristics will not show up well before the actual failure point is reached, and you should be aware that some driving maneuvers can cause momentary "spike" loadings much closer to design (failure) limit, e.g. braking hard while turning, which will increase loading on the front axle.

Like I said, I have two, 180 lb cargo slide trays (empty weight, each), and am otherwise typically loaded. I typically pull away from the curb 245 lbs. above front GAWR, do not get down to front tire max load (for 110 psi max inflation) until 64% fuel, and don't get down to front GAWR until 45% fuel. I don't give it a second thought, but I try not to do stressful maneuvers, and have my brain about 500 yards ahead of the vehicle.
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Old 06-18-2013, 02:29 PM   #49
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Latest on my 390RB Weight Issue

I recently attended Camp Freightliner in Gaffney while having my first year maintenance done there, and got a good look at a bare chassis (no body on it). It lookes like the fuel tank is situated so that 80% of the fuel weight is on the front axle, and 20% on the rear, whereas the water tanks are situated so that the reverse is true (20% of the water weight on the front, and 80% on the rear.

I travel with normal loads, just the two of us, with 43 gallons of water total in all three tanks, i.e fresh water tank 1/2 full, other two empty, and between 50 and 100 gallons of fuel. At those levels, and after several weighings in various configurations, I am typically 290 to 560 lbs. over the front axle GAWR, and 130 to 195 under the rear axle GAWR.

On the way home from Gaffney, I met one of our fellow forum writers, and learned that Berkshires for 2014 will have 275 mm tires instead of the current 255 mm tires to take care of the tire overload problem (usually just in the front). They will also have bigger airbags to take care of the front (and sometimes rear) axle overload problem. Of course, you have to have the same size tires and airbags at all four corners, so I guess the GVWR goes up too.

I don't imagine it's possible to upgrade airbag size once the coach is built, but if I go to all new wheels (maybe aluminum?) I can upgrade to 275 tires, and at least solve the tire overload problem. It looks like the 20 mm (about 0.8") wider tires will be able to clear the wheel wells and frame in the front in a turn, or in the rear even when parked with the bags down, but I'm not certain of it. Of course, I intend to clear this first with the FR Berkshire and FCCC Service folks.

I'll keep you posted. Meanwhile if anyone has already gone this route, please let me know.
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Old 06-18-2013, 02:42 PM   #50
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You can upgrade to a 12000 steer axel and 275 tires. Gaffney did it for me in April. Big improvement. Still limited my the drive train to 33000.
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