Drop hitch me thru the goal posts of life

[tvanwave]

The floor - to top of ball measurement on my F250 is 24 1/2 inches. If I assume (havent measured yet) my AS coupler is at 18.75 inches, I will need to drop my hitch head about 6" to get near level. I have a reese 800/10,000 WD hitch for my AS with a solid hitch head. What MFR of drop shank hitch will work with the set up pictured here?

Tim

[barts]

I'd avoid doing anything until you try it out... the 'stream may well be higher, and the truck hitch will certainly drop significantly once the tongue weight comes to bear.

- Bart

[tvanwave]

Originally Posted by barts

I'd avoid doing anything until you try it out... the 'stream may well be higher, and the truck hitch will certainly drop significantly once the tongue weight comes to bear.

- Bart

New to all of this -- what I understand is the TV & TT ball/ coupler height should be as close to the same as possible before hookup. The WD hitch will level the truck load front and rear after hook up. Adjusting the ball angle should fine tune the TT leveling. OR am I getting this wrong? The ball dropped 3" w/o the WD hooked up. The F250 is the super duty version w/ tow pacakge and extra leaf spring.

[CanoeStream]

You've got two objectives. [love the title of your thread! ]

First and without exception -- get it so that your Airstream is fairly level during the final tow setup with WD bars engaged. Keep that in mind throughout.

The theoretical second objective may not be perfectly achievable. Before hooking up measure the height off the ground of your truck's wheel well surround, front and back. Any spot will do. I measure to the trim at the top of the sheet metal over the wheel cutouts. In a perfect world, after hitching & engaging the WD bars, the front and back index points should settle the same amounts. You & I have a 3/4 ton -- we're not on such a fine breaking point. For maneuverability's sake, it's good to get some of the hitch weight transferred forward to the front wheels. I've fiddled with measuring these heights and it's virtually impossible for me to overdo the WD bars so that the front settles more than the rear.

Think further -- overhitching and torquing so darn hard that you accomplish equal settling of the front & back index points will cause a very rough ride for your Airstream. Hmm... you've got a 34'er. Anybody use as little as 800# bars for a 34? How many use 1000# bars?? Giving your Airstream a softer ride will help it in the end. You've got a fairly generous rear axle weight rating. I'd accept a bit less transfer-forward with your WD setup. On very flat ground, then just how level does your trailer look with WD bars engaged? Figure how much bar drop you need from that if it's still nose high.

At least that's how I'd approach it. Your results may vary...

[tvanwave]

Originally Posted by CanoeStream

You've got two objectives. [love the title of your thread! ]

First and without exception -- get it so that your Airstream is fairly level during the final tow setup with WD bars engaged. Keep that in mind throughout.

The theoretical second objective may not be perfectly achievable. Before hooking up measure the height off the ground of your truck's wheel well surround, front and back. Any spot will do. I measure to the trim at the top of the sheet metal over the wheel cutouts. In a perfect world, after hitching & engaging the WD bars, the front and back index points should settle the same amounts. You & I have a 3/4 ton -- we're not on such a fine breaking point. For maneuverability's sake, it's good to get some of the hitch weight transferred forward to the front wheels. I've fiddled with measuring these heights and it's virtually impossible for me to overdo the WD bars so that the front settles more than the rear.

Think further -- overhitching and torquing so darn hard that you accomplish equal settling of the front & back index points will cause a very rough ride for your Airstream. Hmm... you've got a 34'er. Anybody use as little as 800# bars for a 34? How many use 1000# bars?? Giving your Airstream a softer ride will help it in the end. You've got a fairly generous rear axle weight rating. I'd accept a bit less transfer-forward with your WD setup. On very flat ground, then just how level does your trailer look with WD bars engaged? Figure how much bar drop you need from that if it's still nose high.

At least that's how I'd approach it. Your results may vary...

OK - I'll try the WD set up again and send a few pictures and measures to help ensure I understand what I am doing. The F250 is a 4x4 so the front is fairly heavily sprung. Does the set up site have to be exaclty level or more imporatant that the TV & TT are on the same plane? My drive is paved but has a very slight slope. Thanks for the help!

[tvanwave]

Originally Posted by barts

I'd avoid doing anything until you try it out... the 'stream may well be higher, and the truck hitch will certainly drop significantly once the tongue weight comes to bear.

- Bart

Thanks for the advice - I will try again. I had trouble with 9th grade algebra - is there a relationship to WD hitch installation?

[tvanwave]

Originally Posted by tvanwave

OK - I'll try the WD set up again and send a few pictures and measures to help ensure I understand what I am doing. The F250 is a 4x4 so the front is fairly heavily sprung. Does the set up site have to be exaclty level or more imporatant that the TV & TT are on the same plane? My drive is paved but has a very slight slope. Thanks for the help!

Measurements TV to top of fender wells unloaded front- 39.25; rear- 40.75 inches; to top of ball: 24.25 inches; TV loaded to fender wells front- 39.5; rear 38.5

Measurement to top-inside of AS coupler - 17inches w/full water tank and 1/2 full waste tanks

As photo shows below. The AS hitch is at 17" and the TV at 24.75 so the pre loaded differnece is 7.75 inches. With the weight on the ball the difference is lessned by 2.25 inches (40.75 minus 38.5) SO I need to drop the hitch head by 5.50 inches - right?? (7.75 minus 2.25)

Tim

[tvanwave]

Originally Posted by tvanwave

Measurements TV to top of fender wells unloaded front- 39.25; rear- 40.75 inches; to top of ball: 24.25 inches; TV loaded to fender wells front- 39.5; rear 38.5

Measurement to top-inside of AS coupler - 17inches w/full water tank and 1/2 full waste tanks

As photo shows below. The AS hitch is at 17" and the TV at 24.75 so the pre loaded differnece is 7.75 inches. With the weight on the ball the difference is lessned by 2.25 inches (40.75 minus 38.5) SO I need to drop the hitch head by 5.50 inches - right?? (7.75 minus 2.25)

Tim

Moved the hitch head as far down the drop shank as possible and tilted the ball forward as far as possible. Now top of hitch ball is 21.75 (three inches lower than earlier). SO, if the AS weight drops the hitch by 2.25" then the coupled height becomes 19.5". This is still 2.5" higher than the AS coupler height of 17" at level. IS the drop on the hitch shank I have already the max? The measurment from the top hole in shank to bottom hole is 6.5" so I'm guessing this equates to a 5-3/4 drop shank?

[olddog299]

Two choices. Go with the lowest practical settings on the drop hitch head and call it good. Or, bite the bullet and buy a different hitch head with a greater range of motion. Reese (the hitch manufacturer) makes a head with a greater range of motion, but it may not be what you need. I strongly suggest a call to Reese's engineers for guidance in this matter,

[tvanwave]

Originally Posted by olddog299

Two choices. Go with the lowest practical settings on the drop hitch head and call it good. Or, bite the bullet and buy a different hitch head with a greater range of motion. Reese (the hitch manufacturer) makes a head with a greater range of motion, but it may not be what you need. I strongly suggest a call to Reese's engineers for guidance in this matter,

I have viewed the reese long-drop hitch on their website 'Reese Weight Distributing Shank, Extra Long Drop, 15,000 lbs no. 63971' but cannot tell if it provides extra drop or not compared to what I have. My tow vehicle is a plain old F250 4x4 w/o any lift kits etc and wonder what others have done with a similar tow vehicle. I'm glad to buy the right parts if I know what will work.

becoming unhitched in TN

[Dave Park]

I would mount the trailer, drive for a little while, then pull up at your supermarket of preference and go inside and do some shopping for 90 minutes or so, while the suspension settles.

Then I would take fresh measurements. Given you have a 34 footer, if you measure the ground clearance at the front and back of the body of the trailer, and you see a difference of around two inches or less, I think you're golden.

This is a personal opinion.

[tvanwave]

Defintion: drop - the distance from the top of the shank to the top of the ball platform. If this is an accurate defintion of drop, then would the drop shank I have (pictured here) be providing about 2" of drop? SO, if I bought a 5-3/4 drop shank then I will gain almost 4 more inches of drop ?

[2airishuman]

a 2 INCH difference front/2/back may be golden...

but it is significantly UNLEVEL and will result in UNeven loading of the tires and brakes...

and the axles which may have already settled significantly in 20 years.

looking at the profile of a 34 a 2 inch variance is obvious and too much.
_________

LONGER drop shanks (10 inches +) are widely available...

aluminum, steel, adjustable and custom fabrications.

MOST are rated to 10,000 lbs, (some made from 2.5 stock are much stronger)

while the STRONGER ones are often limited by the ball dimensions used or the tv's receiver.

SEARCH in gooogooo land and at some of the E RE tailers with detailed websites.

it's impossible to predict how much the truck will sink once connected and exactly what shaft drop is needed.

using whatever is available (even a straight bar) to hook up will provide a reasonable approximation of truck squat.

even after getting APPROXIMATELY the correct drop, only a trip to the scales can confirm proper w/d bar tensioning...
__________

my understanding is the RECeiver height is measured INSIDE the box but regardless it looks like the need is 5-7 inches.

cheers
2air'

[tvanwave]

I like the reese extra drop pictuted here. Provides 5.75 inches of drop... but if I need more thene not so good. Is your recommendation to look for a 7" drop and if i need less - OK? I'm worried about some fabricated hitches not having the real rating that they advertise. Thanks for the comments.

[tvanwave]

Forgot to ask... the pin hole to center of ball hole on current shank is 15.5 inches. Some drop shanks I've seen are 10-14 inches long in that same measurement. Will I lose turning ability or risk bumper crushing with a shorter shank length like these?

Tim

[2airishuman]

keep look'n

is the one you've included rated for W/D?

looks 2 me, mehbe knot.

here's another example that IS rated properly.



yes shorter=less clearance 4 turns.

but shorter also = less influence from tongue mass on drive axle (yaw)

cheers
2air'

[Dave Park]

Originally Posted by 2airishuman

a 2 INCH difference front/2/back may be golden...

but it is significantly UNLEVEL and will result in UNeven loading of the tires and brakes...

and the axles which may have already settled significantly in 20 years.

looking at the profile of a 34 a 2 inch variance is obvious and too much.

A 34' A/S has a 31' body, and three axles on 30" centers. with 60" from the front to back axle (5 feet) the axles cover 1/6th of the length of the body of the trailer. Therefore, the maximum 2" difference across the entire body represents a 1/3" difference from the front to back axle (or 1/6" difference between adjacent axles). Remember, a 2" variance means the nose is up 1" and the tail is down 1" from level.

With 7000 lbs dry weight, minus 800 lbs tongue weight, 6200/6=1033 lbs per wheel. With this low loading, a 1/6" difference between the axles is a non-issue, given the axles will take half the difference. A back of envelope calculation shows the rearmost axle would be taking about 2.6% higher load than the front - less than the difference induced by running on wet road. The difference in braking effort - less than that. In this application, uneven brake effort requires either lack of traction or a different rotation speed - certainly greater than the likely difference of a new tire next to a partially worn tire - which is the sort of height difference we're talking about. This worst case is about 12 lbs load difference from the front to back axle, and assumes very very stiff suspension.

Remember, I said "up to" - I'm guessing it'll end up with an arrangement where you have less than 1/2" difference front to back. On that length of trailer I'd be looking for less than 1" front to back. As I said in my previous post, I'd consider it "safe" to tow at 2".

This raises the question why this trailer has three axles instead of two when two would carry the weight and three axles introduce tire wear problems? Distributing shock loads across three more lightly loaded axles reduces transmission of shock energy to the very long frame by one third, allowing them to keep the frame weight down, and to use the standard shell design without heavy reinforcements, while also keeping the center of gravity low. Plus the lovely handling characteristics.

[2airishuman]

lotza good math there.

now if ONLY my 34 showed that loading at the wheelz (it doesn't but it does weigh more) or tongue.

Originally Posted by Dave Park

...Distributing shock loads across three more lightly loaded axles reduces transmission of shock energy to the very long frame by one third, allowing them to keep the frame weight down, and to use the standard shell design without heavy reinforcements, while also keeping the center of gravity low. Plus the lovely handling characteristics.

i like this notion TOO, but leaving OUT 'reinforcements' has created issues...

http://www.airforums.com/forums/f36/...ion-35237.html

http://www.airforums.com/forums/f36/...oor-54952.html

cheers
2air'

[Dave Park]

*grins* You know what they say...

In theory, there's no difference between theory and practice.

In practice, there is.

[Ahzmyrah]

Originally Posted by tvanwave

I like the reese extra drop pictuted here. Provides 5.75 inches of drop... but if I need more thene not so good. Is your recommendation to look for a 7" drop and if i need less - OK? I'm worried about some fabricated hitches not having the real rating that they advertise. Thanks for the comments.

I have a '05 F350 we tow our 31' with and use a Reese "tall" draw bar with a 6" drop. In our original 1980 Airstream manual it suggests that the ball height and hitch height should be about 1/2 inch of each other. After we replaced the axles on the trailer we measured the hitch height with the trailer leveled at 17 1/2 inches and luckily the ball is about 18 inches high with the drop hitch. I drop the trailer onto the ball until it just settles on the hitch, snap the coupler closed and then install the equalizer bars with two chain links and then fully retract the tongue jack. The truck settles and trailer is level at that setting. We have about 25K miles on the set up now with no problems.