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Old 09-16-2011, 12:26 PM   #21
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Originally Posted by Jeep4Two View Post
I think the Wrangler only has the 3.21 with the 6 speed. In reality there are few Jeeps with the 3.21 as common equipment upgrades usually change the gear. All automatics include the 3.73 gearing, and even most 5 speeds end up with the $50 add on charge for the 3.73. The 4.10 is still available on the Rubicon as well.

Mine has the 3.73 (Automatic Sahara).
.

Not knowing before that you had an automatic opens up some other problems. You will probably need an auxialary transmission cooler so that you don’t fry your tranny.

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Funny thing about all this. If you go to the Jeep website and use their "Build Your Own" tool and click on DETAILS for the Trailer Tow Package, they list the hitch as a Class V -

So what does that tell you about consistency.
I think someone at the Jeep printing department messed up…..my F150 doesn’t even have a Class V hitch. The individual pages of the Wrangler and Wrangler Unlimited state either Class I or II hitches.

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Originally Posted by Jeep4Two View Post
I agree you want the heaviest receiver possible when using WDH.

Here's why I'm not worried with the factory hitch (same part on my 2 door rated for 2000,200 as on the 4 door rated for 3500, 350):

Without a WDH, the weight of the trailer tongue rests on the ball, connected to the draw bar that fits into the receiver. The receiver is held with a hitch pin that then serves basically as a pivot point (and retainer) for the draw bar. The weight pressing down on the ball (and thus the draw bar) places pressure DOWN on the trailer side of the receiver and UP on the TV side of the receiver. This would be the same type of force that would be applied if I stuck a crow bar into the receiver and pressed down.

With a WDH things change and we can effectively redistribute the net down force at the receiver (thus reducing downward force (weight) on the rear axle and increasing upward force (weight) on the front axle of the TV, while also adding downward force (weight) to the TT's axle).

This happens by way of the torsion bars attached to the A-frame of the trailer that then connect to WDH hitch on the vertical portion of the draw bar shank. The result is that the down forces (weight) at the shank get redistributed by way of the two attachment points on the vertical part of the WDH shank and the torsion bars of the WDH. When pressure is applied to the vertical portion of the shank at the top (top pin of the WDH Head) pressing toward the TV --> and pressure at the bottom of the shank (Bottom Pin of the WDH head) is applied away from the TV <-- the net result is LESS upward force (weight) on the front of the receiver. The weight at the front of the receiver doesn't change.

I like to think of it like this: If you had an L shaped crow bar and stuck one end into the receiver and had the other end pointing to the ground. One person holds the horizontal portion and pushes down with a constant force. Another person puts their hands one on top of the other on the vertical portion and applies a forward force with their top hand and a reverse force with their bottom hand. The result of the 2nd person adding the forward reverse pressure will reduce the net effect of the downward force.

Based on this, I believe that the stresses inside the receiver are actually reduced (lessened) as the actual fulcrum is the WDH Shank. The weak link in this process is actually the vertical portion of the shank.

I hope that makes sense. It does to me, but then again I've been reading too much about all this and had to draw this out on paper to get the physical forces acting in the whole system make sense
You have a very good grasp of how a WDH works. But 1 thing to consider is this: Without a WDH, and using the pin as a pivot point, the hitch shank is pushing up on the front of the receiver, and pushing down on the rear of the receiver. When using a WDH, that is now reversed…..pushing down on the front of the receiver, and pulling up on the back of the receiver. It is this stress that concerns me about a receiver that is not meant to be used with a WDH. There may be no problem with that…..I just don’t have that type of knowledge to know for sure.
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Old 09-16-2011, 01:59 PM   #22
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Yes on the Aux Cooler. It's on my list. Heck, folks in the Jeep Wrangler (JK since 2007) with the automatic highly recommend it in general (even without towing) as the tranny can get way too hot when off road at low speeds. I've got the B&M cooler on my to do list very soon.

I agree on the printing dept. The 2 door has a class I weight rating, 4 door Class II and both have same 2" receiver hitch from the factory (option).

The question I have is this. Does the WDH actually completely reverse the pressures in the receiver and on the hitch bar (shank)?

I would think no, since if it did completely reverse it you would have the effect of negative weight at end of the receiver bar. This shouldn't be the case since even a properly adjusted WDH will still allow some sag in the rear suspension (at least a significant portion of the dead tongue weight would still be pressing down on hitch at the end of the receiver bar (shank)). If it were completely reversed I would imagine it would create lift in the rear suspension and introduce sag in the front. In addition to have that happen we would have to create enough lift from the WDH to have a negative force (UP Force) at the hitch ball.

I think I'm starting to My brain hurts
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Old 09-16-2011, 02:09 PM   #23
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Originally Posted by Jeep4Two View Post
The question I have is this. Does the WDH actually completely reverse the pressures in the receiver and on the hitch bar (shank)?

I would think no, since if it did completely reverse it you would have the effect of negative weight at end of the receiver bar. This shouldn't be the case since even a properly adjusted WDH will still allow some sag in the rear suspension (at least a significant portion of the dead tongue weight would still be pressing down on hitch at the end of the receiver bar (shank)). If it were completely reversed I would imagine it would create lift in the rear suspension and introduce sag in the front. In addition to have that happen we would have to create enough lift from the WDH to have a negative force (UP Force) at the hitch ball.

I think I'm starting to My brain hurts
Hmmm, this might make my brain hurt, also. I would say yes to your question. You are correct that a properly adjusted WDH should put the lost weight back on the TV front axle, and the rear axle will still settle some. But if you were over do things, putting too much weight on the front TV axle and the trailer axles, then the rear axle could actually have less weight then before the trailer was hooked up. With really stiff spring bars, I would imagine it would be possible to completely lift the rear TV wheels off of the ground, putting all of the tongue weight and rear axle weight on the front TV axle and the trailer axles.
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Old 09-16-2011, 02:27 PM   #24
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I think you guys are over-thinking this:
1) no matter what WDH you have or how it is set up, it will NEVER actually lighten the load on the rear springs. There will always be some tongue weight.
2) the WDH will place some weight BACK onto the TRAILER frame. The trailer pivots on the single axle, the WDH puts some of the wqeight on the trailer axle, forcing the trailer suspension to compress slightly.
3) the published trailer weight rating is NOT the actual theoretical capacity of the receiver hitch. It is an overall capacity of the vehicle. The simple strength of the receiver hitch in question far exceeds any published GCWR for the vehicle. Again, you can hoist you JK from the point suspended from a crane. I have seen it done.
4) you actually want a slight rear weight bias in the TV when towing, it keeps the trailer from wagging the dogs tail.
5) the receiver is a sleeve, the pin does not act either as a fulcrom or a pivot point. It cannot.
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Old 09-16-2011, 04:29 PM   #25
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Even though this has gotten away from the orginal question of pulling an A Cabin type trailer with a Jeep Wrangler, I think it has turned into a interesting discussion. Hope others chime in here so it is just not a 2 way discussion.

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I think you guys are over-thinking this:
1) no matter what WDH you have or how it is set up, it will NEVER actually lighten the load on the rear springs. There will always be some tongue weight.
Using my WDH, I lessen the load on my rear axle by 440 lbs. 320 lbs go to my front TV axle, and 140 lbs. go to my trailer axle. Those figures don’t add up exactly, which may be contributed to the 20 lb. increments of the quarry scales that I used. You can check out all of my stats here if you want something to put you to sleep: Weight Stats

The trailer tongue does not change for any given load in the trailer, sitting on level ground. Only the effects of the tongue weight are changed using a WDH….it is redistributed.

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2) the WDH will place some weight BACK onto the TRAILER frame. The trailer pivots on the single axle, the WDH puts some of the wqeight on the trailer axle, forcing the trailer suspension to compress slightly.
Agreed.

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3) the published trailer weight rating is NOT the actual theoretical capacity of the receiver hitch. It is an overall capacity of the vehicle. The simple strength of the receiver hitch in question far exceeds any published GCWR for the vehicle.
Agreed. But there is no way to actually know what the limits of any given hitch are. That is why I think it is always good to have a heavier hitch rating than the trailer that is in tow.

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4) you actually want a slight rear weight bias in the TV when towing, it keeps the trailer from wagging the dogs tail.
Agreed.

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5) the receiver is a sleeve, the pin does not act either as a fulcrom or a pivot point. It cannot.
I was quoting you from a previous post, to use that as an analogy. You wrote:
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Originally Posted by Jeep4Two View Post
The receiver is held with a hitch pin that then serves basically as a pivot point (and retainer) for the draw bar. The weight pressing down on the ball (and thus the draw bar) places pressure DOWN on the trailer side of the receiver and UP on the TV side of the receiver.
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Old 09-16-2011, 05:16 PM   #26
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All very good points.

My main concern revolves around ensuring I'm not putting any undue stresses on the hitch receiver by using a WDH. Based on my understanding I'm not. I'm redistributing part of the load to the TT axle using the forces of the spring bar. This in turn reduces the effective weight at the receiver due to the rotational forces at the shank, thereby allowing less weight to be borne on the TV rear axle and giving weight back to the TV front axle. The 'rule, is that this happens in thirds divided equally among the three axles, but in reality never truly is perfect.

My worry was that a reversal of the forces on the front and rear of the receiver could be an issue. After reading more into it and reading some detailed threads on the physics (statics) of the WDH system in now understand that in order to cause upward force on the front (TT SIDE) and downward force on the rear (TV SIDE) of the receiver that you would have to have spring bars strong enough and tight enough to create an effective negative hitch weight.

If you managed to do that you would get a reduction of weight on the rear axle and increase of weight on the front axle of the TV which would create a towing nightmare.

My end conclusion is that a properly adjusted WDH will not cause any additional stress at the receiver of the TV hitch, rather lessen the load carried there through redistribution. End result is my Jeep and trailer sitting level and towing well, and safely without having my Jeep looking like it's all stuck-up with it's nose in the air.

I was incorrect earlier when I stated that the hitch pin is a pivot point. The receiver bar is where the forces are applied to the TV
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Old 09-19-2011, 02:24 PM   #27
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Reese 60065 hitch showed up today, but it's raining and the shank shipped from a separate warehouse and won't be here till tomorrow anyway.

I'll post back my results of leveling and how things go once installed this week.

Anyone else have any input on WD Hitches in the mean time?
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Old 09-21-2011, 08:55 PM   #28
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Finally got a chance to get the WD Hitch setup and all adjusted. Here are my experiences and some questions.

First, my statement from the 16th is WRONG:

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My worry was that a reversal of the forces on the front and rear of the receiver could be an issue. After reading more into it and reading some detailed threads on the physics (statics) of the WDH system in now understand that in order to cause upward force on the front (TT SIDE) and downward force on the rear (TV SIDE) of the receiver that you would have to have spring bars strong enough and tight enough to create an effective negative hitch weight.
While there is still no 'negative' hitch weight (just redistributed weight across the 3 axles). The part about reversing the forces inside the receiver is the wrong part. After hooking up the hitch you can see the change an angle of the WD Shank into the receiver and clearly see that it is pushing up on the rear (trailer side) of the receiver and down on the front (TV side) of the receiver tube. The weight carried at the receiver is of course the same, but the reversing of the forces inside the hitch provide the shift of weight in the TV.

This was unexpected for me - but I'm a noob to this stuff.

So my questions:

1) My Shank has about 3" behind the hitch pin and about 11" going out to the rear toward the trailer to the vertical bar of the shank. It doesn't go all the way through the receiver tube (about 1" short of going completely through. Should this be a concern?

2) Considering the length that is outside the receiver, the length of the horizontal part of the shank adds a lot of extra distance (compared to the shorter draw bar I was using without the WD Hitch). That gives the weight of the trailer more leverage against the vehicle. Is this a problem? Should I trade out for a shank with a shorter horizontal length? (The Curt 17120 that I have has a 12" distance from hitch pin center to center pin on the horizontal part of the shank). The only option I've found that has sufficient drop is the Convert-A-Ball cushioned WD Shank (AMAC1 at eTrailer). It has a 6 3/4" distance from hitch pin center to center pin.

The other concern with the longer Curt 17120 shank is that my safety chains aren't long enough to connect to the hitch. If I keep the 17120 how would I address the chain issue? Just a direct replacement of existing chains and hooks? On the upside my breakaway wire is the right length LOL.
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Old 09-22-2011, 02:07 AM   #29
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So my questions:

1) My Shank has about 3" behind the hitch pin and about 11" going out to the rear toward the trailer to the vertical bar of the shank. It doesn't go all the way through the receiver tube (about 1" short of going completely through. Should this be a concern?
No, this is not a concern, the shank has been engineered to universally fit the receiver hitch as the receiver tube will invariably be different with different manufacturers.

Quote:
2) Considering the length that is outside the receiver, the length of the horizontal part of the shank adds a lot of extra distance (compared to the shorter draw bar I was using without the WD Hitch). That gives the weight of the trailer more leverage against the vehicle. Is this a problem? Should I trade out for a shank with a shorter horizontal length? (The Curt 17120 that I have has a 12" distance from hitch pin center to center pin on the horizontal part of the shank). The only option I've found that has sufficient drop is the Convert-A-Ball cushioned WD Shank (AMAC1 at eTrailer). It has a 6 3/4" distance from hitch pin center to center pin.
I don't have the answer for this, my gut feeling is there should be no worries.

Quote:
The other concern with the longer Curt 17120 shank is that my safety chains aren't long enough to connect to the hitch. If I keep the 17120 how would I address the chain issue? Just a direct replacement of existing chains and hooks? On the upside my breakaway wire is the right length LOL.
The chains can be changed easily enough, you may want to talk to your dealer about needing the chains being replaced. Also, you can find chains at Lowe's, Home Depot, or inquire at a local metal fabricating supply company. You can remove the chains and take with you to know you have a match in the size and capacity of the current chains.
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Old 09-22-2011, 08:15 AM   #30
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Many hitch shanks have 2 pin holes. Use the furthest back on the shank if possible. Some receivers has 2 pin holes....use the furthest forward if possible.
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