Weights - What's it all mean?

[Pat Cassity]

So Yesterday, I decided to take my Suburban and 27' International to the nearest CAT scale. I came away with some numbers but I believe I need some help determining what they mean. Also, I realized when I left that I did not separate front and rear axel weights. Here is what is on the printout:

1st weight
Suburban only (unhitched) - 5780lbs ( gross weight)

2nd weight
steer axle - 6860 lbs
Drive axle - 5480 lbs
Gross weight - 12340

The Suburbans GVWR is 7200lbs. The 'curb weight' is 5846 lbs
It would appear that I am ok as far as not exceeding my TV's GVWR but what confuses me is the trailer weight of 5480 lbs. Airstream states that the unloaded weight of the 2014 27' International to be 5600lbs. I have added approximately 150 lbs ( if not less) into the trailer and all water and holding tanks are empty. Is this the result of the WD hitch?
Your thoughts?

[SteveSueMac]

Hi. Good start but I think you need some additional info to really see what's going on. Here's a link to a CAT scale "how to": http://catscale.com/how-to-weigh

Can you post pics of your tickets? You need one where the front (steer) and rear (drive) axles if the tow vehicle are on their own (unhitched) so you know what you start with on each axle. Then when you connect the trailer you weigh again (preferable without applying weight distribution) to see the impact on the tow vehicle. This is where you'll see (probably) a few hundred pounds get lifted off the steer axle and a few hundred loaded on to your drive axle. Then you can apply weight distribution to dial in what you need to restore the front axle to whatever the desired restoration is (for some it's 50% for some it's 100% - your tow vehicle's documentation will provide a recommendation). Don't worry if the trailer seems light - those published weights are max. Mine cants exceed 7200 but weighs in at 5880 loaded for camping.

Also, it's best to do all those weights with a full tank of fuel in your tow vehicle, and full propane and fresh water tanks on your trailer (full black tanks would be ideal for max load - no pun intended). If you travel with people, pets, luggage and gear, have that with you too. You're trying to set a baseline fully loaded for camping.

See if that link helps any. It might take a few trips to the scales at first (I think I went 6 times with several weigh ins each time) before I understood what I needed to see. Odds are you'll get it faster than me! :-)

Good luck!!

[Pat Cassity]

Here are pictures of the Cat Tickets

[HowieE]

It appears you were not placed correctly on the scales. I say this because of the excessive weight of the steering axle during the loaded weight.

A cat scale has 3 plates designed to weigh the steering axle, dive axle, and trailer individually while the combination is on he scale.

I would go back and before driving on the scale study the plates and position your truck on the 2 smaller plates so the steering and drive axles are on individual plates. The hitch up and return with the trailer. The 3 sets of axles should be on 3 different plates for this weigh for this weight.

It is not necessary to get weights while loaded with your WD hitch loaded and unloaded.

[Pat Cassity]

Based on the Cat link I didn't position my vehicles correctly. When weighing the TT and TV hitched together I position the Suburban entirely on scale number 1 and the trailer entirely on scale number 2. I then unhitched and weighed the suburban. The Suburbans unhitched weight is 340lbs less than the first weight due to my wife and I not being in the vehicle.

[gmw photos]

Pat,
If you want to know all of your numbers, including how much weight is being "restored" to your steer axle by the action of your weight distributing hitch, you need three passes:
Truck only
Truck and trailer with weight bars engaged
Truck and trailer with weight bars not engaged

And, as has been stated, the steer axle goes on platform one, drive axle on platform two, and trailer axles on platform three.

PM me if you would like some more details.

[J. Morgan]

Actually the way you pulled on the scale tells quite a lot when taken in account with the suburban only weight.

What this means is that in the act of hooking the trailer, the tongue weight plus the "weight" of the WD hitch, you transferred 1080 lbs from the trailer to the Suburban.

An additional ticket might tell you more about weight transferred to the front axle of the Suburban if you were to weigh both axles of the Suburban on separate platforms both hooked to the trailer and unhooked.

[J. Morgan]

I think that the most important thing is to see how the combination drives at this point, with adjustments to meet the end of having the unit handle as best as possible.

In my minds eye, the 1100 lb transfer seems pretty close to ballpark right.

[Pat Cassity]

Although, I didn't position the vehicles correctly to establish axle weight, it would appear from the weights that I obtained that I am well within the limits of both my TV and trailer. I am perfectly happy with the way the two handle on the road. I do plan to return and re-weigh based on your recommendations. What I really needed to establish was that my current setup is safe. I have been in the market for a different tow vehicle but it would seem at this point that the only advantages that may give me is the ability to 'get off the line' a little faster.

[SteveSueMac]

Originally Posted by Pat Cassity

Although, I didn't position the vehicles correctly to establish axle weight, it would appear from the weights that I obtained that I am well within the limits of both my TV and trailer. I am perfectly happy with the way the two handle on the road. I do plan to return and re-weigh based on your recommendations. What I really needed to establish was that my current setup is safe. I have been in the market for a different tow vehicle but it would seem at this point that the only advantages that may give me is the ability to 'get off the line' a little faster.

Yup! I think you're looking for 2 pieces of information and have one already (you're not overtaxing your axles). I think the other piece of safety info you want is how to dial in the weight distribution correctly so your front/steer axle is properly "reloaded" based on your tow vehicle manufacturer's recommendation. A rule of thumb is fender measurements (e.g., if your front wheel well is 40" from the ground without the trailer and 42" with the trailer attached, you want it back to 40" with WD applied). But it's best to see the exact impact on the scales to know for sure.

[J. Morgan]

I think your Suburban will do fine. My 08 5.3 equipped pulls my heavier than average 31 footer just fine, I passed very near the highest point in Texas on Tuesday at speed limit .

[J. Morgan]

Additionally I would speculate that the tongue weight of the trailer is about 600 lbs, then it might be assumed that the the WD hitch is throwing another 500 lbs on the tow vehicle, which by virtue of geometry is going to push much of this 1,100 lbs forward onto the steer axle.

[Ron Gratz]

Originally Posted by Pat Cassity

Suburban only (unhitched) - 5780lbs ( gross weight)

2nd weight
steer axle - 6860 lbs
Drive axle - 5480 lbs
Gross weight - 12340

---When weighing the TT and TV hitched together I position the Suburban entirely on scale number 1 and the trailer entirely on scale number 2. I then unhitched and weighed the suburban. The Suburbans unhitched weight is 340lbs less than the first weight due to my wife and I not being in the vehicle.

If you were not in the Suburban when the first weighing was done,
the unhitched weight should have been 5780+340 = 6120#.

The trailer's weight would be 12340-6120 = 6220#.

The load added to the TV when hitched with WD applied would be 6860-6120 = 740#.
Assuming the WDH causes a load equal to 15-25% of TW to be transferred to the trailer's axles,
the TW would be in the range of 870 to 990#.

Ron