Can't adjust Reese hitch

[Ron Gratz]

Originally Posted by dkottum

What difference does changing the tilt (angle) of the ball/coupler connection have to do with weight distribution? Isn't weight distribution a function of lift applied to the w.d. bars?

Yes, weight distribution is a function of lift applied to the WD bars -- along with distance from ball to lift brackets and distance from ball to midpoint between TT axles.
However, the amount of "lift" is a function of WD bar stiffness and the amount of "bend" which can be created by pulling up on the bar ends.

Increasing the rearward tilt of the ball mount causes the rear end of an unloaded WD bar to move farther below the lift brackets.
This means the bar end can be lifted a greater distance -- creating more bar curvature and more lift force (i.e. more downward force on the A-frame).

Or are you saying changing the tilt of the ball/coupler connection is also lowering the w.d. bars, and if the same length of chain is used to connect the bars to the A-frame, more lift is applied to the w.d. bars? (Realizing that unless the w.d. bars aren't tilted down somewhat, little or no lift is available.)

Yes, although not unanimous, that does seem to be the majority opinion of those posting in this thread.

I think Andrew Thomson's article above describing how tilting the ball and bars downward keeps the tow vehicle and truck more stable in turns, and helps keep the trailer in-line with the tow vehicle as well as helping it return to center after turns is a more in important function of tilting the ball and w.d. bars downward?

Some setups require little or no rearward tilt in order to generate sufficient load distribution. Some require much or maximum tilt.

IMO, the primary function of a WDH is to add load back onto the TV’s front axle and to remove some of the load which was added to the rear. I believe any increase in yaw stability resulting from rearward tilt is a secondary benefit. Andrew appears to agree with this based on his statement: “Though the primary job of the equalizing hitch is to transfer weight to the front axle of the tow vehicle, how the weight is transferred impacts handling.”

Andrew goes on to state: “However, the main reason for the rearward angle is to change the direction of weight transfer so we have additional traction in sharp turns and additional stability at high speeds.” But, if by “additional traction” Andrew means more load on the TV axles, his ensuing narrative and his table of test results at the top of page 52 seem to show that extreme rearward angle causes the load transfer to remain essentially the same as TV/TT articulation increases. If there is no change in load, where does the additional traction and stability come from?

Furthermore, if you convert the front and rear heights from the table on Page 52 to estimated load changes using an assumed spring rate (I used 100 lb/inch/wheel, but any value can be used), the results indicate the angled mount at 22° gave virtually no load change on the TV while the vertical mount at 22° gave a load increase of about 100 # (using my value of 100 lb/inch/tire).

Of course, simply changing the TV/TT articulation from 0° to 22°should not change the load on the TV (as was the case for the angled mount) so I’m guessing there is an error in the data for the vertical mount. I’m also guessing that Row 2 of the table (“Tow vehicle with trailer in straight line”) applies only to Row 3 and does not apply to Row 5. If so, subtracting Row 5 from Row 2 would give erroneous results for Row 6.

IMO, the test results do not support the hypothesis that increasing the rearward angle gives additional traction in sharp turns and additional stability at high speeds. And, even if there is benefit at articulation of 22°, there is no evidence of any benefit at articulation around +/- 5° which is the range of interest for sway control. Perhaps this is why Andrew recommends using a friction sway control when the WDH does not have integrated SC.

In short, I am not convinced that extreme rearward tilt of the ball mount is a substitute for other means of sway control -- the bicycle forks argument notwithstanding.

Ron

BTW -- If we want to make this a Minnesota thread, we lived in Ely prior to becoming full-time RVers.

[dkottum]

Ron, I surely never intended to indicate downward tilt (if needed) for weight distribution was less important than to assist in sway control and handling in turns but rereading I guess that's how it sounds. Weight distribution is the priority.

Thanks for pointing that out. I do believe Andrew T. uses a number of seemingly insignificant strategies in setting up hitches, including downward tilt of the w.d. bars, shortening of hitch stingers to decrease ball distance to tow vehicle rear axle, changing to lower profile tow vehicle tires for less sidewall movement, selecting tow vehicles based on stability rather than size, to get excellent results from tow vehicles that leave many of us just shaking our heads.

While we may believe tilting the w.d. bars at an extreme downward angle is of little benefit, lots of little benefits become a great improvement.

[Msmoto]

The important message see is that a heck of a lot of trial and error is often required. My goal was to get the trailer level, weight on the front and rear axles of my TV about equal, and have the entire rig drive comfortably.

One variable is of course, what we carry in our TV, in the bed or rear storage area, and how this affects the weight on the TV axles before the AS is connected. In my case, 60 gallons of diesel, generator, air compressor, heavy ground blocks, all of which alter the GVW of my TV.

Across the scales: TV Front 4430 lb, rear 4390, AS 7200.

My suggestion to anyone is to attempt to set up as per the guides from Reese, here is a starter video

https://www.youtube.com/watch?v=7731SkSgEqE

Then adjust as more knowledge is gained.....like over 10,000 miles...LOL

[Ron Gratz]

Originally Posted by Msmoto

My suggestion to anyone is to attempt to set up as per the guides from Reese, here is a starter video

I am very happy to see that the new WDH installation video from Reese specifies that the WDH adjustment is based only on front wheel well height.

At 7:00 it states that the final height should be within 1/2" of the unhitched height.
This later is defined as being "the same or {up to} 1/2" higher" than unhitched.

The new specifications imply the Front Axle Load Restoration should be about 50% to 100% -- consistent with what Reese now states in some of their installation instructions.

100% FALR means that the load restored to the front axle via the WDH is equal to load removed from the front axle when the TT is attached with no WD applied. The net front-axle load change would be zero -- i.e. load on front axle is same before hitching and after hitching with WD applied.

This means that the added load carried by the rear axle is equal to about 75-80% of tongue weight and the load transferred to the TT's axles is equal to about 20-25% of tongue weight.

While you might end up with the front axle load equal to the rear axle load, that is neither an intended nor an expected result.

Ron

[HowieE]

The above video in general is a good illustration of the principles of a WD hitch. It was not a setup for a Reese SWAY CONTROL system.

However I like to go a bit further, especially when working with an Airstream and bring in those consideration when setting up a WD Sway control system.

First of the axles used on and Airstream require that the final position of the trailer be parallel to the ground. To accomplish this it will take a bit longer in the final adjustments.

Second I like to tow the combination to the point of installation having traveled at least 200 ft. in a straight line. This ensures that things are as straight as they will be while on the road.

Once on place disconnect the trailer and go through the set up as described above. It will be necessary to separate the TV and trailer a few inches while working but do so without moving the TV steering wheel. Before moving the TV, and without the trailer load on it, place a piece of masking tape on the front and rear fenders of the TV and mark a measurement on each. This is just a reference number so the number means nothing at this point. As you go through the set up keep 2 things in mind. You are attempting to get the front axle measurement of the TV as close as possible to the reference mark you just made. Not exact but close and limited by the type of suspension your TV has, A frame suspensions are more critical than I beam as they tend to effect tire ware as they go out of alignment with height changes. You do not want a Lower measurement as that indicate you are overloading the front axle.

The placement of the yokes over the trailer frame are not as critical as noted in the video as the chain angle has No Effect on anything. Yes if off by an in. or more you may want different yokes more for looks than mechanics.

What is important for the sway control systems is that the bars have to ride fully seated on the saddles, be it a Duel Cam system or Straight Line system. If setting up a sway control system leave the bolts holding the Duel Cam trailing arms loose to the frame until the last thing. Likewise leave the yoke adjusting nuts loose on the Straight Line system. Make all adjusts to the system to get the ride configuration you want an then while the bars are loaded on the saddle hit the point of contact between the bars and saddles with a 2 pound hammer. This shock will seat the bars on the saddle and you can now tighten the mounting nut on the Duel Can trailing arm to the trailer frame or set the adjustment nuts on the Straight Line yokes.

Since the sway control aspects of this type of hitch is ALL IMPORTANT these steps ensure things are in fact straight. I find it necessary to mark the bars left and right as they are not always the same length as supplied from the factory. If the bars are slightly different in length the system can be additive to sway rather than damping to sway.

[HowieE]

Forgot to mention.

When all is done measure the frame height front and rear of the trailer while on concrete or a very flat roadway. Try for less than a 1/2 in. difference. Keep in mind if the trailer is riding high in the front that increases the tongue weight. If high in the rear that decrease it. Both will effect steering so get it close.

[rideair]

Wow, had I know there was this much to setting up a hitch, I never would have been able to do it. I just remember someone saying, make sure the ball is about 19 3/4 inches high, the end of the WD bar in the resting position should be about 6-8 inches off the ground (adjust head pitch to make this happen) this should allow you to hook up to about the number 8 link in the chain.

This should get you real close.

Enjoy,

[xrvr]

[QUOTE=HowieE;1711237]Forgot to mention.

When all is done measure the frame height front and rear of the trailer while on concrete or a very flat roadway. Try for less than a 1/2 in. difference. Keep in mind if the trailer is riding high in the front that increases the tongue weight. If high in the rear that decrease it. Both will effect steering so get it close.[/QU. Per ride height, do you have it backwards?

[HowieE]

rideair

You lucked out. The trailer riding parallel to the road requirement just does not applies to a single axle trailer. You can drop on the ball at any height an go. However from the picture above it does look like you did it anyway.

The set of a WD hitch become intuitive after you have done it a while but is not that easy to give written instruction to those that may be new to it.

avionstream.

I may have not been clear with this comment
Keep in mind if the trailer is riding high in the front that increases the tongue weight. If high in the rear that decrease it. Both will effect steering so get it close.

It refers to the trailer not the TV. This is a function of the fact that Airstream trailers have separate axles without the center conspirator common on most SOBs. As the front of the trailer is raised less weight is applied to the front trailer axle and thus the load on the tongue goes up. SeeSaw 101.

[xrvr]

Not convinced yet. Agree to disagree.

[slowmover]

Good thread.

[xrvr]

Don't forget about the center of gravity.

[switz]

Before starting this exercise to setup the WD hitch, a few preliminaries need to be addressed.

Make sure the tire pressure is set the same in all of the trailer tires, preferably with a digital pressure gage.

Make sure the tow vehicle tires have the same pressure in each pair (both front and both rear).

Nice to know information is the actual tire weight loading at each location. If one side is heavier than the other, one may have to compensate for this or reload the payload in the trailer.

Make sure the selected work area is as close to level as possible, both front to rear and left to right.

Changing the payload in either vehicle will impact the setup work just accomplished. Depending on the weight margins on the axle loads and GVW ratings, one may be okay with minor weight changes, But going from a full 54 gallon water tank to an empty one will definitely have an impact.

[Ron Gratz]

Originally Posted by HowieE

---As the front of the trailer is raised less weight is applied to the front trailer axle and thus the load on the tongue goes up.---

Originally Posted by avionstream

Don't forget about the center of gravity.

You're both correct.

Lifting the tongue will decrease the front axle load (It also will increase the rear axle load). The tongue load will increase, but not nearly as much as the decrease in front axle load.

Lifting the tongue will cause a slight rearward movement of the location of the CG. This will cause a decrease in tongue load. The effect of CG movement will cause the tongue load increase to be reduced by about 25%.

Lowering the tongue will decrease the tongue load. This will have a slight effect on the "tongue weight" calculated from scales measurements if there is any appreciable drop in the rear of the TV with TT attached and no WD applied.

Ron

[dickschaak]

Originally Posted by Ron Gratz

Yes, weight distribution is a function of lift applied to the WD bars -- along with distance from ball to lift brackets and distance from ball to midpoint between TT axles.
However, the amount of "lift" is a function of WD bar stiffness and the amount of "bend" which can be created by pulling up on the bar ends.

Increasing the rearward tilt of the ball mount causes the rear end of an unloaded WD bar to move farther below the lift brackets.
This means the bar end can be lifted a greater distance -- creating more bar curvature and more lift force (i.e. more downward force on the A-frame).

Yes, although not unanimous, that does seem to be the majority opinion of those posting in this thread.

Some setups require little or no rearward tilt in order to generate sufficient load distribution. Some require much or maximum tilt.

IMO, the primary function of a WDH is to add load back onto the TV’s front axle and to remove some of the load which was added to the rear. I believe any increase in yaw stability resulting from rearward tilt is a secondary benefit. Andrew appears to agree with this based on his statement: “Though the primary job of the equalizing hitch is to transfer weight to the front axle of the tow vehicle, how the weight is transferred impacts handling.”

Andrew goes on to state: “However, the main reason for the rearward angle is to change the direction of weight transfer so we have additional traction in sharp turns and additional stability at high speeds.” But, if by “additional traction” Andrew means more load on the TV axles, his ensuing narrative and his table of test results at the top of page 52 seem to show that extreme rearward angle causes the load transfer to remain essentially the same as TV/TT articulation increases. If there is no change in load, where does the additional traction and stability come from?

Furthermore, if you convert the front and rear heights from the table on Page 52 to estimated load changes using an assumed spring rate (I used 100 lb/inch/wheel, but any value can be used), the results indicate the angled mount at 22° gave virtually no load change on the TV while the vertical mount at 22° gave a load increase of about 100 # (using my value of 100 lb/inch/tire).

Of course, simply changing the TV/TT articulation from 0° to 22°should not change the load on the TV (as was the case for the angled mount) so I’m guessing there is an error in the data for the vertical mount. I’m also guessing that Row 2 of the table (“Tow vehicle with trailer in straight line”) applies only to Row 3 and does not apply to Row 5. If so, subtracting Row 5 from Row 2 would give erroneous results for Row 6.

IMO, the test results do not support the hypothesis that increasing the rearward angle gives additional traction in sharp turns and additional stability at high speeds. And, even if there is benefit at articulation of 22°, there is no evidence of any benefit at articulation around +/- 5° which is the range of interest for sway control. Perhaps this is why Andrew recommends using a friction sway control when the WDH does not have integrated SC.

In short, I am not convinced that extreme rearward tilt of the ball mount is a substitute for other means of sway control -- the bicycle forks argument notwithstanding.

Ron

BTW -- If we want to make this a Minnesota thread, we lived in Ely prior to becoming full-time RVers.

Ron,
You have been gone too long to consider yourself a Minnesotan. It is possible to restore your status but it is very involved. A check would have to be done on your winter clothing, an accent check would have to be done and a check of your recollection of envied sayings: ie, ya sure, Ohhhhhhhh and many others. It is possible though.

[dickschaak]

I am absolutely blown away by reading the many fantastic posts to this thread. Some of the respondent are so intelligent that I have no idea what they are talking about. I still like to read them though. It really is amazing the wealth of knowledge available for the asking. It is a good testament to the caliber of individuals that own Airstreams. Now that I own one again I hope I get smart too.

[Bob662]

Howie, GREAT post! Thanks.

[Wishbone]

Originally Posted by dickschaak

I am absolutely blown away by reading the many fantastic posts to this thread. Some of the respondent are so intelligent that I have no idea what they are talking about. I still like to read them though. It really is amazing the wealth of knowledge available for the asking. It is a good testament to the caliber of individuals that own Airstreams. Now that I own one again I hope I get smart too.

WOW I could not agree more !!!