campercajun
Central Texas Hill Country
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I have the same Reese Strait-Line hitch with Dual-Cam HP sway control, and I don't have that much tilt on my hitch head, but I have a 3/4-ton truck and my trailer is higher off the ground than yours. I think the main thing that caused the guy to have to put that much down-angle on the hitch head is that the hitch bar coming from your truck's receiver is not level, but is rising at a significant angle. Surely this is not a factory receiver hitch for your Toyota?
The tech who adjusted the hitch head to that angle did so because he had to in order to level the truck and trailer and transfer the proper amount of weight to the TV's front axle. Although it looks strange, the steep angle on the hitch is caused by the hitch bar being mounted at an upward angle itself. As long as everything is tight and the rig is level, though, you should have no problems, except that the steep hitch head angle makes the WD bars ride fairly low at the ends. You may occasionally hear them drag if you don't angle into service station driveways and go across street gutters and other low places at a slight angle, to keep both sides from lowering at the same time.
2003 GMC Sierra Crew HD; 6.0L; Prodigy
2006 Thor Tundra 30RL-DSL; Reese Strait-Line & Dual-cam HP
2001 Honda Elite Scooter
Jim & Gayle Bryant
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Golden_HVAC
Fulltime, CA, USA
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Hi,
When hitching up to the trailer, a good tip is to lower the hitch into place, lock the hitch onto the ball, then raise the hitch about 4" so it is easy to tighten up the chains without putting a lot of pressure on the bar that locks the chains into place.
Also mark the chain with a black marker, so you will know what link to hook onto the bracket. With the hitch in a raised position, putting on and taking off the chains is really easy, not something that can break your arm if the handle slips. Yes the camper next door was taken to the hospital once many years ago with a broken arm.
Fred.
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wittmeba
Roanoke, Va
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BenK,
Quote:It looks like your trailer is pointing up in the pictures, which is
wrong, as that has the trailer axle caster incorrect and it will not
steer (follow) correctly. It will be easier to induce sway or exacerbate
any sway that 'will' come along.
I have never heard of this before. How would you have 'caster' with a round axle on a welded plate attached to leaf springs? Caster applies to vehicles because the wheels turn. Placing the center of the axle behind the top pivot of the steering is what makes the caster work by causing the wheel to lag behind the front most point.
This is a castering wheel:
This is not a castering wheel:
Also, I realize the tilt angle of the head will affect the tension on the spring bars, but isnt the adjustment primarily in the chain length?
* This post was
edited 08/20/08 08:51am by wittmeba *
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tvman44
Southwest Louisiana
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Sounds normal to me with weight distributing bars. You adjust the angle of the ball to increase or decrease the tension of the bars.
Papa Bob
1* DW "Granny"
1* 2008 Brookside Sunnybrook 32'
1* 2002 F250 Super Duty 7.3L PSD
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BenK
SF BayArea
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Joined: 04/18/2002
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wittmeba wrote:snip....
I have never heard of this before. How would you have 'caster' with a round axle on a welded plate attached to leaf springs? Caster applies to vehicles because the wheels turn. Placing the center of the axle behind the top pivot of the steering is what makes the caster work by causing the wheel to lag behind the front most point.
snip....
Also, I realize the tilt angle of the head will affect the tension on the spring bars, but isnt the adjustment primarily in the chain length?
Goes way back when still in college and working full time as a designer
in a small motor controls company. Assigned to architect the trailer
for a contract with the Navy to supply shore power to submarines in
for drydock work. Since they didn't want to run their onboard
generators, these trailers took 480VAC and knocked it down to whatever
that voltage was (getting old). Big one was 450KVA, IIRC.
First test tow with next door biz's 6 ton dump truck had the trailer sway
like mad. Lucky we decided to use that 6 ton truck, as any of our
light duty picups/4x4's would have had an accident.
Called the axle folks and talked to an engineer. After about 20
minutes he finally said: "kid, you know what caster is...yes...it's
kind of like that".
For decades referenced that till someone called me on it over at the
Suburban forum. Stopped making that reference till just this year
when poking around for info to help someone solve their trailer sway
issues.
Came across this image and now can prove that a live axle with leaf
springs do have 'caster'.
Why most all rear live axle with leaf springs will have the leading
leaf eye lower than the trailing. Why most all front live axle leaf
springs will have the leading leaf eye higher than the trailing.
This is the traditional caster diagram for the 'FRONT' axle.
This is the new to me diagram showing how a leaf spring live axle
will have caster designed in.
-Ben Picture of my rig
1996 GMC SLT Suburban 3/4 ton K3500/7.4L/4:1/+150Kmiles orig owner...
1980 Chevy Silverado C10/long bed/"BUILT" 5.7L/3:73/1 ton helper springs/+329Kmiles, bought it from dad...
1998 Mazda B2500 (1/2 ton) pickup, 2nd owner...
Praise Dyno Brake equiped and all have "nose bleed" braking!
Previous trucks/offroaders: 40's Jeep restored in mid 60's / 69 DuneBuggy (approx +1K lb: VW pan/200hpCorvair: eng, cam, dual carb'w velocity stacks'n 18" runners, 4spd transaxle) made myself from ground up / 1970 Toyota FJ40 / 1973 K5 Blazer (2dr Tahoe, 1 ton axles front/rear, +255K miles when sold it)...
Sold the boat (looking for another): Trophy with twin 150's...
51 cylinders in household, what's yours?...
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BenK
SF BayArea
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Forgot to address the head tilt and the WD bar tension.
by tilting the head back, the bars are also tilted or more correctly,
pointed downwards.
This increases the distance from their end to the trailer tongue.
So 3 links for both situations will have more tension with the head tilted back.
Also, since the distance from the WD bar end to the tongue is larger, during
whopdeedos, the WD system will have more bar tension to work with and *NOT*
unload the system as much if the bar ends were closer to the tongue.
There is also the turning or during sway that will have the WD bars
tension increased by that off line sway/turn. This is how the cams
work, as they will increase the WD Bar tension as the trailer goes
off center line.
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BarneyS
S.E. Lower Michigan
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wittmeba wrote:
Also, I realize the tilt angle of the head will affect the tension on the spring bars, but isnt the adjustment primarily in the chain length?
They both work together. The more tilt, the more links you can have under tension for the same amount of weight transfer. You try to adjust the tilt so you have a minimum of 5 links under tension when you have the amount of weight transfer you need or want. In some cases, you need to adjust head tilt to give clearance for the WD bars to operate in tight turns.
Head tilt, spring bar weight, chain links used, receiver rigidness, bar clearances, tow vehicle spring compression, and sometimes even trailer tongue configuration and strength, are all factors that must be considered in getting the WD hitch set up correctly - but primarily, the head tilt is used to adjust the number of links necessary to get the weight transfer you want.
Barney
2004 Sunnybrook 30FKS TT
Hensley "Arrow" 1400# hitch
2002 Ford F250 Super Duty, 7.3L PSD
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wittmeba
Roanoke, Va
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BenK and BarneyS,
Thanks for the replies. This is very educational for me.
BenK,
I understand what you are saying, but in the case of a trailer caster does not apply (NON-Kingpin axles). That would suggest that the center does not remain in the center. With a Kingpin, certainly, you can change the angle which WILL relocate the center relative to vertical, but you CANNOT with a concentric axle.
Ill give BarneyS the 'Best Answer' award for the answer to tilt angle and spring bar tension. Both...thats what I suspected too. It appears you would make major changes with the chain adjustment (different link) and fine tune for level with the head angle.
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BenK
SF BayArea
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that was my hangup back then with that axle engineer...there isn't a
king pin, therefore no caster, in my mind. After about 20 minutes
over the phone, in exasperation, he just said it's kind of like
caster and to go ahead and lower the leading eye.
Noodling it ever since found that image and think that if the center
line of the axle is 'not' centered on the leaf stack, then there is
a lever arm that attenuates that effect. Positive vs negative caster
and whether that is a steer or follow axle. Think that center line
of this lever arm is like the king pin center line.
Back on that original trailer design and the tremendous sway we
experienced.
The only thing we changed was to the recommendation that engineer told
me to do. Drop the leading eye about 2 inches below the trailing eye.
Solved and had that done to the other trailers. They were all towed
down to San Diego from the San Francisco Bayarea with no sway. Pintel
and eye with no WD hitch system. Surge brakes.
Simply readusting the trailer tongue from pointing up to down has
solved most of the sway issues I've ever helped with.
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BenK
SF BayArea
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did a fast/crude modification of the above image to show where the live
axle tube would be and the reference to the off axis angle.
Again, since there isn't a king pin, there for no 'rotation' at this point,
this isn't 'caster' per say.
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