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doorgunner · 05-09-2007, 05:03 PM

Today I drove over to the scales to weigh my Burb and AS. 93 2500 454 2wd, and 73 29' ambassador. Both stripped , only front seat in burb others removed. AS empty, no battery and no propane tanks. Tha first time thru with AS attached steering axle 3080lb, drive axle 3700 lb. trailer 5020 lb. gross 11800lb. Then I disconnected the AS and drove the burb thru steering 2940lb, gross truck 6280lb. So for all you engineers Rip this apart and let me know how long I have to live.Looks to be 500 lb of tongue wt. that sounds ok for an empty trailer. It was also interesting to see that only 140lbs was transferred to the steering axle with the WD bars in place. Any way cost me 7 bucks and a little time. just interesting to know stuff. DG

Fyrzowt · 05-09-2007, 05:05 PM

It's interesting to see your figures. I need to do the same myself. I'll keep watching here to compare others real-world weights...
Did you get the drive axle weight the second time through? (Or did I just miss it?)
Dave

doorgunner · 05-09-2007, 06:09 PM

Dave, basic subtraction 6280-2940=3340. I know owning an AS you are always into the addition mode, weight and $$. Anyway the trailer weight was listed as empty 4820, tongue wt 485 in some airstream table some member was kind enough to link to. but I forgot to bookmark it! I'm kinda wondering how far off the factory numbers are anywho. DG

wkerfoot · 05-09-2007, 06:13 PM

Quote:

Originally Posted by doorgunner

Dave, basic subtraction 6280-2940=3340. I know owning an AS you are always into the addition mode, weight and $$. Anyway the trailer weight was listed as empty 4820, tongue wt 485 in some airstream table some member was kind enough to link to. but I forgot to bookmark it! I'm kinda wondering how far off the factory numbers are anywho. DG

Here is the link, again: http://www.airstream.com/airstream/p.../weights-1.pdf

Bill

doorgunner · 05-09-2007, 09:36 PM

Thanks Bill, yup their weight was low.

AgZep · 05-09-2007, 11:44 PM

For what it's worth, we performed a similar experiment on our rig right after we bought it, and again right after we departed for full timing. To make a long story short, the factory-published empty weight was only off by maybe 100 lbs (low of course), and that could have been due to things like the hitch hardware, heater compartment cover locks and so forth.

We thought we loaded up pretty light when we took off, but we were actually about 250 lbs over gross on the trailer. It felt fine, but we dutifully stripped out the excess weight anyway. We always had plenty of suspension travel left, and it always towed beautifully. I guess I'm a believer in careful weight management.

BillTex · 05-10-2007, 06:24 AM

Hey DG, well you are putting a greater load on your rear axle than your front, not necessarily a problem.
I would think more importantly are you getting the same amount of drop front/rear when you hook up?

Bill

nickcrowhurst · 05-10-2007, 05:39 PM

Quote:

Originally Posted by doorgunner

It was also interesting to see that only 140lbs was transferred to the steering axle with the WD bars in place.

DG, your figures look good to me. Bear in mind that without the WD bars, the front axle would have been unloaded by the tongue weight pushing down, and the TV pivoting about a point near the rear axle. The bars have thus transferred considerably more than 140 pounds. To calculate the WD chain tension to bring the front axle back to its original height, you could check this thread out:
http://www.airforums.com/forums/f464...sis-19236.html?
I would be well pleased with your figures.
Nick.

doorgunner · 05-10-2007, 07:18 PM

BTex. UM uh well the way I set my tension on the bars is to jack as high as I can then put the chains on as tight as I possibly can. Not very scientific but it works for me. Then I eyeball the TV for level look.
Nick-thanks for the insight, your other thread and your explanation took a few times thru to set in for me.
Agzep I'm thinkin a whole lotta folks are overloaded.but there must be some margin for error. Thanks Nick

BillTex · 05-11-2007, 06:09 AM

Quote:

Originally Posted by doorgunner

BTex. UM uh well the way I set my tension on the bars is to jack as high as I can then put the chains on as tight as I possibly can. Not very scientific but it works for me. Then I eyeball the TV for level look.
Thanks Nick

DG, it is not just a matter of getting your chains as tight as possible. Although I have found that it does take a LOT of force as the trailer weight increases. Really it is about finding the correct amount of force to achieve proper weight distribution. A quick way of checking this is verifying that the front and rear of your TV drop an equal amount when you hitch up. The amount of this drop (distribution) can be varied by just how much tension you put on the chains (or bars). Not to worry, it SOUNDS like you are in pretty good shape.Getting the tow vehicle to compress fairly evenly front-to-back indicates that you have proper weight distribution. This provides several benefits for towing: it presses all four tires down equally on the road surface to maximize traction, steering and braking. This helps to keep your headlights level when towing at night instead of having them point up to the sky. Proper weight distribution also helps to minimize the "porpoising" or bouncing that typically comes from driving over sectioned or rough roads. This bouncing is at its worst when no weight distribution is used at all, but should be minimized if not eliminated when properly transferring the weight. In addition, proper weight distribution also helps to minimize the risk of bottoming-out or hitch dragging. The Spring Arms are designed to flex, so you will still get a cushioning effect when driving over bumps and dips. When a WD Hitch is properly transferring tongue weight, the corresponding amount of friction should be generated at the same time to maximize sway control for that specific towing set-up.
If proper weight distribution is not achieved, the rear of the tow vehicle would end up squatting more than it should (and the front of the tow vehicle could potentially lift up or lighten). This would cause a "floaty" feeling in the handling, as steering, traction and braking would be reduced. The headlights would point up too high, the vehicle will "porpoise" or bounce, and the increased amount of tongue weight pressing down on the back of the vehicle would allow the rear to squat more than it should. This would not only place the hitch area closer to the ground than it should be when towing, not having Spring Arms that are stiff enough would also allow the rear of the vehicle to drop even more when driving over bumps and dips. This increases the risk of bottoming-out or hitch dragging. These drawbacks in performance would be more severe on vehicles with soft suspensions, and less severe on vehicles with stiff suspensions.

Bill

Chuck · 05-11-2007, 08:01 AM

Quote:

Originally Posted by BillTex

...A quick way of checking this is verifying that the front and rear of your TV drop an equal amount when you hitch up.

that'll give you a ball-park idea, but it doesn't account for the differences in suspensions of front and rear axles, and how much the springs are already compressed by the truck's own weight.

If I stand on my rear bumper, I can make it bounce up and down like a diving board. If I stand on the front bumper...it hardly moves.

the only way to really know how much weight is being transferred is with a scale.

BillTex · 05-11-2007, 08:26 AM

Quote:

Originally Posted by Chuck

that'll give you a ball-park idea,

Exactly...I would make sure I didn't drop 3" in the rear and nothing up front for instance...

Quote:

Originally Posted by Chuck

the only way to really know how much weight is being transferred is with a scale.

Which DG has already done...

Regards, Bill

nickcrowhurst · 05-11-2007, 10:34 AM

Quote:

Originally Posted by Chuck

that'll give you a ball-park idea, but it doesn't account for the differences in suspensions of front and rear axles, and how much the springs are already compressed by the truck's own weight.

If I stand on my rear bumper, I can make it bounce up and down like a diving board. If I stand on the front bumper...it hardly moves

My experience is the same as Chuck's. There is no way I can get my truck anywhere near level. The front suspension is hard, so as to support a heavy diesel engine. and the rear suspension is soft so that the unladen rear end doesn't bounce around. The end result is that when the scales tell me the weight is correctly ditributed by the WD bars, the back end is significantly lowered in relation to the front end. Levelling front and back could be done by using perhaps 2000 pound WD bars (if they existed), but a concientious observer would notice that the rear wheels were not touching the ground.

Nick.