Visit our Popular Forums

Al and Missy · 02-19-2014, 04:40 PM

Well, I took my trailer to get weighed today and I was surprised by the result. I weighed it at a moving and storage company but they say their scales are calibrated quarterly and the weight of the truck alone looks right so while they are not a CAT certified scale, could they be off this much?

Truck alone, with driver, 1/2 tank fuel, and the WD head in the receiver
Front 3480
Rear 2800
Total 6280 (against a GVWR of 7200#)

TV/TT combo, TT with water tank full, one full and one half-full propane, and 1 group 27 battery
Front 2940
Rear 4200 (this is an overload condition)
TV GVW 7140
TT 5080

So, subtracting TV GVW from Combo TV GVW gives the tongue weight of 860#. Add that to the Combo TV axle and I get 5940# for an almost empty TT. If I subtract for the water, propane tanks, propane and battery, I get 5510 which should compare to the "unloaded vehicle weight" as specified of 4920#.

I have seen numerous references here to AS' weights being optimistic, but this seems unreasonable, even given the modifications which were to remove the gaucho and add two recliners and some storage between them and the front wall.

Another post will deal with my WD setup, so let's not get into that here. At this point I am concerned with what appears to be a reduction of my cargo capacity to around 370# over and above water, propane and batteries.

Is it worth a trip to a CAT scale? The empty truck weight would seem to indicate about 1000# available payload for a 1/2T truck so that seems reasonable.

Thanks,

Al

Ridgerunner3 · 02-19-2014, 05:14 PM

I am reading this on my iPad so I can't see all of your TV / TT info. What is your trailer and what is your truck? Can you explain the process you used at the scale? How did you come up with a front and rear trailer axle weight. Your process may be the problem. There are several threads discussing the process to use at a CAT scale. An error in the process can result in considerable head scratching.

perryg114 · 02-19-2014, 05:22 PM

Well how are you separating the weights of the front trailer axel and rear trailer axel. They are really close together. If there is a drop off where the scale is, it will throw off the readings. If the scale is higher than the concrete pad the wheel on scale will read higher than it should. Also how many gallons does your fresh water tank hold? Mine holds 50 gallons and I think the newer trailers have even larger fresh water tanks. Water is 8 lbs per gallon.

Perry

overlander63 · 02-19-2014, 06:43 PM

Unless your truck has a bunch of lead bars somewhere, It's too heavy. My 3/4 ton truck only weighs 6500 pounds, and our 1/2 ton shop truck only weighs about 4700.

Al and Missy · 02-19-2014, 07:10 PM

Ridge runner: truck and trailer info in my signature, but here goes:
TV -2006 F-150 lariat 4x4 with 5.4L
TT- 2001 Safari 25A

Hopefully this will clarify what I did. The scale is quite long. I made two weights for the truck alone and three with the trailer attached. With the trailer attached I made two passes, one with the WD engaged (bars in place) and one without the bars. In all cases, the first weight was the front axle of the TV. The second was both truck axles, or the TV gross weight. The third weight for the two trailer passes was with the trailer axles only on the scale.

Ridge runner and perryg114:
I did not try to separate the weights of the two trailer axles.

Overlander63:
The truck is a Lariat 4x4. By spec it is quite heavier than my 1999 4x2. I presumed it was the weight of the larger engine, transfer case and front differential. GVWR is 7200#, so at the measured weight there is around 1000# of capacity left which seems about right for a "half ton" pickup.

All:
From those experiments it is straightforward to calculate the parameters of interest. The difference between the TV gross weight and the front axle is the TV rear axle.The difference between the TV gross weight without the trailer and with the trailer without WD yields the tongue weight. Add the tongue weight to the trailer axle weight without WD and you have the TT gross weight as loaded. Subtracting off the weight of the things that (as least as I understand it) are not included in the factory unloaded weight (water, propane and tanks, and battery, which may be generous), and you should get a number comparable to the "unloaded weight", again, at least as I understand it.

I should add that in my previous day job I was involved with designing and integrating mobile communications suites so I am familiar with the engineering basis for these calculations. Where I may be deficient is in the area of AS' interpretation of the terms in their specifications but there is very little leeway as far as the TT GVWR goes and it seems clear that I can only add about 380# to my trailer after water, propane, and a battery.

One error I made was I mis-remembered my water capacity. I used 35 gallons at 8# per gallon and my tank is 39. So my water weight is off by 32#.

If my methodology is incorrect, I'd appreciate pointers on how to correct it.

Thanks,

Al

Al and Missy · 02-19-2014, 07:28 PM

For these weighings, the trailer was about 2.5" low at the coupler. Somehow I messed up my calculations for WD ball height. I think this may change the distribution of the weight but will not change the total weights with WD disengaged.

Al

Ridgerunner3 · 02-19-2014, 07:34 PM

I may be out in left field but I don't think the readings you have are correct. I recommend that you go to a CAT scale with your TV and TT loaded as you would for a typical camping trip. Get the following weights all on the same trip.

First Run:
WD engaged with a level TT
Put the TV front axle on one scale pad
Put the TV rear axle on the second pad
Put the both TT axles on the third pad
get the weight

Second Run:
WD dis-engaged
Same setup as first run for location of axles on the scale pads.
get the weight

Third Run:
TV by itself
Front axle on one pad
Rear axle on the second pad
get weight

This will give you a good basis for understanding your TV & TT weights and WD setup. From this you can calculate your tongue weight and make adjustments to your WD setup.

Some recommend that you weigh each trailer tire and axle individually. I have not ever gone through weighing each TT axle and wheel position individually.

gmw photos · 02-19-2014, 07:45 PM

And to follow on from what Bud said, the following is from a post made by Ron G, which gives an easy to follow fill-in-the-blank form to tell what the numbers mean. As always, thanks to Ron for this. And now....over to Ron.... :

========

If you want to use the scales data to determine tongue weight, and if you want to get the maximum information about your TV/TT combination and how well your weight distrtibution system is working, you need data from three weighings. Second and third weighings usually are done at a lower cost.

And, you need to find a scales with at least three separate weighing platforms so you can separately measure all three axle loads at the same time. Most, perhaps all, CAT scales have this feature.

If you need any help in interpreting the scales results, just post the numbers. There are several ORF members who can help with the calculations.

First, the TV and TT should be loaded approximately as they would be for camping.

Second, the weight distribution system should be adjusted as it normally would be for towing.

Then, I would do the following:

Weighing #1 -- TT attached and Weight Distribution Activated
Let Front Axle Load be "FA1"
Let Rear Axle Load be "RA1"
Let TT Axles Load be "TT1"

Then, while in same position on scales, take
Weighing #2 -- TT attached and Weight Distribution Not Activated (WD bars unloaded, but hanging in place)
Let Front Axle Load be "FA2"
Let Rear Axle Load be "RA2"
Let TT Axles Load be "TT2"

Then, drive off scales and drop TT. Return to scales and take
Weighing #3 -- TV only -- TT Not Attached
Let Front Axle Load be "FA3"
Let Rear Axle Load be "RA3"

From the above values, you can calculate:

TV weight = FA3 + RA3

Gross Combined Weight = (FA1 + RA1 + TT1)
{should also be equal to (FA2 + RA2 + TT2) if scale weights are correct}

TT Weight = Gross Combined Weight - TV Weight

Tongue Weight = (FA2 + RA2) - (FA3 + RA3)

Load Transferred to TT Axles
when WD System is Activated = TT1 - TT2

This procedure should get you on and off the scales fairly quickly and still provide all the data you need.

Al and Missy · 02-19-2014, 08:09 PM

I guess tomorrow I'll hit the nearest CAT scale. Maybe the fact that I wasn't making all the measurements at the same time is contributing an error to the process.

Thanks for the quote from Ron. I think his process is essentially what I was doing except for the fact that I was not making the measurements at the same time nor was I at the same spot on the scale.

I'll update tomorrow when I have CAT data.

Thanks again to all!

Al

Al and Missy · 02-19-2014, 08:15 PM

I'm going to do the CAT weight just as I did this one for two reasons:

1. I want to clearly see the difference between the two scales, and

2. The answer will affect how I will load for a trip. If my previous results are correct I don't want to drive to the CAT scale with an overloaded truck or trailer and I only have (per this weighing) about 380# of wiggle room.

When I get a better handle on the true unloaded weight I will know better what I can carry and where I should carry it.

Thanks again to all!

Al

Garfield · 02-20-2014, 03:54 PM

FWIW I own a 2001 SS Safari and my sticker UVW of 4850 lbs is accurate -- remember that doesn't include the weight of fluids, battery and dealer-installed options.

Al and Missy · 02-20-2014, 04:28 PM

He never knows what time it is.

The same goes for the man who weighs his trailer twice! I'd like to believe that there was a problem with the moving and storage weights from yesterday, but I can't figure out what is going on with the CAT weights.

The scale I used has three separate platforms. I parked with the TV front axle on the front (steer axle), the TV rear axle on the middle (drive axle) and the TT on the back platform (trailer). First weigh, with WD on gross weight was 12,200#. Then, without moving the combination on the scale, I jacked up the tongue, disconnected the WD bars, and lowered the trailer off the tongue jack. The gross weight for this came out at 11,980#. This makes no sense. The truck and trailer never changed position on the scale and the total weight should have been the same.

I'm reviewing the data and trying to figure out what happened. The only things I can come up with are they may have done the first weight while I was standing on the scale, or something to do with the brakes. The sign says to release the brakes, which I did for the first weigh. But when I started raising the tongue everything started moving, so I set the brake and left them on for the rest of the measurements.

And try as I may, I didn't do apples to apples. Yesterday I was in the truck and today I wasn't, and today I left the WD bars hanging for tests 2 and 3 and yesterday I put them on the ground. I'm trying to incorporate corrections and when I have more data I'll report back, but the preliminary conclusion is that the trailer is substantially overweight.

Al

gmw photos · 02-20-2014, 04:38 PM

Quote:

Originally Posted by Al and Missy

He never knows what time it is.

The same goes for the man who weighs his trailer twice! I'd like to believe that there was a problem with the moving and storage weights from yesterday, but I can't figure out what is going on with the CAT weights.

The scale I used has three separate platforms. I parked with the TV front axle on the front (steer axle), the TV rear axle on the middle (drive axle) and the TT on the back platform (trailer). First weigh, with WD on gross weight was 12,200#. Then, without moving the combination on the scale, I jacked up the tongue, disconnected the WD bars, and lowered the trailer off the tongue jack. The gross weight for this came out at 11,980#. This makes no sense. The truck and trailer never changed position on the scale and the total weight should have been the same.

I'm reviewing the data and trying to figure out what happened. The only things I can come up with are they may have done the first weight while I was standing on the scale, or something to do with the brakes. The sign says to release the brakes, which I did for the first weigh. But when I started raising the tongue everything started moving, so I set the brake and left them on for the rest of the measurements.

And try as I may, I didn't do apples to apples. Yesterday I was in the truck and today I wasn't, and today I left the WD bars hanging for tests 2 and 3 and yesterday I put them on the ground. I'm trying to incorporate corrections and when I have more data I'll report back, but the preliminary conclusion is that the trailer is substantially overweight.

Al

Al,
Ok, so that is a diff of 220 pounds. The scale has a tolerance of 20 pounds. My guess is, you weigh....around 200 to 220 pounds ?

So give us all the weights from all three separate weights, and lest's see if we can make sense of it.

BTW, I am a little surprised the weighmaster allowed you to be messing around disconnecting, etc, on the scale. Generally that is considered to be "unacceptable".

SteveSueMac · 02-20-2014, 05:12 PM

Al,

Ron G (whose method was posted earlier here) calculated my personal weight based on my tickets and my explanation of sheer confusion about similar stuff - which I caused by weighing once in and once out of the truck. Sounds like you may have done the same. No prob - like I said, it took me a half dozen times to finally figure it out. You still have 4 to go for that record and odds are you won't need that many :-)

If you're sitting in your tow vehicle, do exactly that for each weigh in.

Also, I think they want you to drive off and come back around for each adjustment.

Keep going! You'll get a baseline soon!!

gmw photos · 02-20-2014, 05:18 PM

For my own trips over the scales, since with my pickup trucks, I have to be out of the cab to reach the call button, I always make sure I am standing off the platform when asking for the weight.

Al and Missy · 02-20-2014, 08:13 PM

I adjusted the CAT weights for the apparent error of weighing while I was still standing on the scale. I didn't get separate TV axle weights in 3, only gross for the TV and TT . The CAT numbers, when adjusted for measurement differences, are within spitting distance of the numbers from the moving and storage scale.

I asked how to handle the separate weighs and they said doing it on the scale was OK. As I was doing the last weigh I got a couple of semis behind me. Next time I'll go around.

Adjusted CAT ......1-WD On ......2- WD Off........3- TV Only
TV Front ................3170.............2960
TV Rear..................3540.............3900
TT..........................5200.............5120. ..............5860
TV GVW..................6710.............6860........ .......6140

Tongue 720
TT GVW 5920
TT "extras". 504 full water, propane and tanks, microwave, LCD TV, battery
"Unloaded" 5416 Actual
"Unloaded" 4920 Spec
Overweight 496

I suppose it is possible that replacing the gaucho with two recliners and some storage furniture added nearly 500# but that seems like a lot.

Comments?

Foiled Again · 02-21-2014, 12:55 AM

Clothing - any woman will tell you that you only weigh yourself with your shoes off, and no heavy clothing on. Preferably in underwear. Weight without shoes will be 2 lbs. less than with - without a jacket, sweater, sweatshirt - or a pocket full of coins, a pocketknife and keys - almost another 2 lbs.

Look at the clothing you store in the Airstream. I'll bet you have 20-25 lbs per person. And I'll also bet that about 7-10 lbs you wear all the time, and the rest languishes in closets, drawers and plastic containers. Kitchen crap is one of my weaknesses. I got rid of about 20 lbs of stuff with the new Airstream.

The little stuff adds up. Edit it ruthlessly.

Paula

Al and Missy · 02-21-2014, 12:32 PM

You have to be careful picking and choosing data from different sources, even from one set of CAT weighs to another as neither I nor the scale operator were diligent about controlling conditions. IMO the best data to use is my last posted adjusted set. Depending on how you calculate it, tongue weight comes around 700#.

Nevertheless I concur that I need to dial in a little FA weight. The problem is exacerbated by the fact that the trailer was a little tongue down for these measurements. I have corrected that and now I need to readjust the WD. Thanks for looking. When I get it dialed in I'll take another data set and post it.

Al

gmw photos · 02-21-2014, 01:02 PM

Al,
From your posted numbers from the CAT scale, I was unsure how you obtained the weight of the truck, in weighing three. Was it on the scales by itself, with the trailer totally off the scales ?
That is why I was attempting to use your previous day numbers of the truck alone.

Again, just to reiterate, ( mostly for a new person looking at this for the first time ) my procedure is this:

first weigh is as I arrive at scales, truck, trailer, WD hooked up.

drive off scales, disconnect weight bars, take second weigh pass.

drive off scales, disconnect trailer, leave in parking lot, take third pass truck only.

Bill M. · 02-21-2014, 02:15 PM

What is your GVW and axle load on the trailer sideplate? I have found listed empty trailer weight to not be a useful number. Our 25', 1988 Excella has a GVW of 6800 lbs and a axle loading of 6300 lbs. I just walked to the next site and read the tag on the mid 90's 25' next door. It says 8800 lbs GVW. So your number sounds awful low to begin with. When we are on the road we have 5600 lbs on the trailer axles. I have not done the other weights.