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Airstreamer67 · 01-17-2008, 08:52 AM

SilverCabin, as you know, the weight transfer bars fit into the recepticles on the tow vehicle hitch right under the hitch ball. In turn, these are bolted onto an attachment plate on the AirSafe mechanism, which slides into the tow vehicle's two-inch hitch recepticle. Therefore, the AirSafe mechanism part of the hitch is on the tow vehicle side of the equasion, while the weight transfer bars and ball are on the trailer side. In other words, the AirSafe mechanism is placed between the tow vehicle and the weight transfer bars/ball. So, when the weight transfer bars are cinched-up, they are pushing up on the Airsafe mechanism, which, in turn, pushes up on the back of the tow vehicle and thus transfers the desired amount of weight to the front of the tow vehicle. This means the weight transfer bars/ball are cushioned via the AirSafe air hitch just like the trailer is. The shock and jerk caused by the traditional hard hitch connection is largely gone. It all works very well.

Regarding the several inches of extra length to fit the AirSafe mechanism on, I have noticed absolutely no problems. In fact, the cushioning effect of an air hitch is said to reduce sway. For sure, it definitely smoothes-out the ride for both the trailer and the tow vehicle.

No more popped rivets and separated frames for me. No sir. No more.

SilverCabin · 01-17-2008, 10:18 PM

Thanks 2air and Phil. I was kind of thinking that myself.

Airstreamer67: Thanks for the explanation. I'm still having trouble visualizing it, and now that I'm thinking it's not for me, trying to understand is an academic exercise. So, don't feel obligated to enlighten me. Here's my confusion:

When I hitch up with my Equal-i-zer, the weight transfer is through the hitch shank to the receiver. The bars pull up, making the hitch head tilt toward the truck, which forces the shank against the top of the receiver, raising the rear of the truck and the front of the trailer, and lowering the front of the truck and the rear of the trailer. If everything is set-up right, you end up with a trailer parallel to the road and the truck squatting the same front and rear.

With the Airsafe, there is an airbag between the hitch head and the receiver. Somehow, that bending force needs to get to the truck's receiver. If you hitch up with no air in the bag, and attach the bars, what happens? It seems like the bending force would lift the hitch until it hit the stop at the top making the suspension aspect of the airbag moot.

I'm a EE not an ME so maybe that's my problem trying to see how this works to provide suspension (through the airbag) and weight transfer at the same time. Again, I've decided my set-up doesn't need the Airsafe, so I'm just trying to understand the manufacturer's claims.

Randy

2airishuman · 01-17-2008, 11:17 PM

that's a pretty good description of how w/d redistributes load rodney...

i'm no m.e. or e.e. but i did sleep in an airstream last night!

the pix safari rick posted are of the model withOUT w/d potential.

only the class 5 and above a-s hitches have w/d...

looks to me like there are 2 almost parallel tie rods on each side that project the w/d forces past the airbag...

they allow compression at the bag, but the spring bars can still transfer downward force to the front axle...

at least that's my guess about this from the a-s website photos.

and could be absolutely incorrect.

IF anyone with this set up has visited a cat scale, they could confirm this.

cheers
2air'

Phil Gobie · 01-18-2008, 06:17 AM

I am not sure I can explain it but I think I understand it. If you can visualize a vertical slot instead of the pivoting arms where the weight transfer pivot point is they would actually work in the same way. the vertical slide could allow for the weight transfer to the front and still slide up and down. the pivot does the same.

Airstreamer67 · 01-18-2008, 08:01 AM

Randy, if the AirSafe were hitched "out of air," I think the whole thing becomes a hard connection, like you said. There no longer would be air in the bag providing a fluid-like connection. Kind of like what an airbag suspension system would be without air.

2Air and Phil, your explanations sound right to me.

Or, I might be like the Wizard who, while rising uncontrollably in the basket of the balloon while Dorothy and Toto watch in horror, shouts, "I can't go back. I don't know how it works."

May all of you have a great 08 on the road, even if we don't know how it all works,

Mike

Ron Gratz · 01-18-2008, 04:38 PM

Quote:

Originally Posted by SilverCabin

With the Airsafe, there is an airbag between the hitch head and the receiver. Somehow, that bending force needs to get to the truck's receiver. If you hitch up with no air in the bag, and attach the bars, what happens? It seems like the bending force would lift the hitch until it hit the stop at the top making the suspension aspect of the airbag moot.

I'm a EE not an ME so maybe that's my problem trying to see how this works to provide suspension (through the airbag) and weight transfer at the same time. Again, I've decided my set-up doesn't need the Airsafe, so I'm just trying to understand the manufacturer's claims.

The upward force applied to the rear ends of your weight distribution bars exerts a pitch-axis torque on the hitch head. There is also a vertical (downward) force applied to the hitch head which is equal to the tongue weight minus the amount of load which is transferred to the TT's axles.

The vertical force adds load to the TV's rear axle and removes load from the front axle. The pitch-axis torque causes load to be removed from the rear axle and causes load to be added to the front axle. The question is -- how does the torque get transmitted from the TT side of the AirSafe to the TV side?

The torque is transmitted via the AirSafe's tie rods. The WD system causes the rods at the top of the hitch to be placed in compression. The rods at the bottom are placed in tension. This "push-pull" action produces a CCW (when viewed from the driver's side) torque on the TV side of the hitch. The tie rods produce the necessary torque; and weight distribution results.

The vertical (downward) force on the hitch head is carried by the air bag.

Ron

Phil Gobie · 01-19-2008, 05:36 PM

Yea yea thats it!

plowboy · 01-19-2008, 07:14 PM

I bought an air ride receiver for our Ford E150 van and Tradewind combo. It arrived a day before we were to depart to The International Rally in Salem Oregon.
The Receiver was VERY low (about 2"-3") off the ground, properly inflated. With the thing sitting that low down, I was afraid of bottoming out going down the road.
Be very carefull to check your tow vehicle for compatability before ordering.

Airstreamer67 · 01-20-2008, 05:20 AM

Ron, thanks for that explanation. You nailed it, as usual.

Plowboy, I wonder why the hitch is hanging so low. Did the hitch weight bring down the back of the van? If that is what happened, then I assume you did not get the hitch that allows the use of weight-distribution bars? It seems the bars would be able to bring the height up. However, if the weight of the hitch is enough to lower the van to within two or three inches of the ground, then I would question the van's suspension.

Mike

remcolent · 01-30-2008, 07:07 AM

I would realy like to see some more detailed pics / drawings of the AirSafe hitch.
I'm thinking of making my own hitch for the F350 with the airbag just under the bumper of the car.
Thinking of making it a not removable system with a reciever tube.
Where I either fit the reese WD hitch or our plain european hitch.

So I don't want to just copy the AirSafe but change it to suite my needs.
I'm thinking of using 2 smaller airbags so I have room in between for a reciever tube,
This will make the whole construction a lot wider that the AirSafe but as it is hidden under the F350 that would not make a problem.
Regards
Remco