Thoughts on which hitch to use please.

[jondrew55]

Lol. Got that right.

Originally Posted by ROBERT CROSS

It's all in the set-up...Power over an inanimate object.

Then there is road harmonics which is something none of us can control.


Bob
🇺🇸

[Air Cruiser]

Thanks so much for the sharing of information you all have been doing, I am very thankful! Your “personal experience information” is invaluable in helping us decide which hitch is right for us.

Majorairhead — I love your pics of your hitch showing how you clean & inspect your hitch. It’s very inspiring to see and read the correct things to do.

PatLee — Thanks for adding the information re: JC’s preferred hitch — calling them was on my “honey do” list given me by my DH.

mgblake13 — We had not heard of a “genyhitch” before, so thanks for that info — will definitely research those.

tbrowne — I thought you more than likely had a reason for asking about our tv, but wasn’t certain the connection. Now wondering, when we do upgrade to a “newer” tv which will be gently used and a diesel, is there a chance the hitch we purchase now may not work with the new tv? Just thinking this through.

aftermath — Thanks for sharing re: “2’-itis jealousy”, we had that same thing going on here for some time. We have had our ‘99, 25’ for 10 1/2 years, did a quick and “dirty” 3/4” plywood laid over the twin bed area to make a Queen. That was great for sleeping but not easy to make bed or for dressing. We really enjoyed our “Lola”, but not the bed. Took years to actually pull the plug and move up to the 27’ — actually getting ready for retirement gave us the “push”.

Ekbruster — Thanks for mentioning the “Husky centerline hitch”, we had not heard of that hitch before, or at least do not recall it; will read up on the Husky.

Many thanks again for everyone taking the time to post your thoughts and I hope if anyone else might have more, please share.

Deb

[pteck]

Originally Posted by ROBERT CROSS

Prove it don't just say, it is just your opinion.

Stream Happy

Bob
����

If you're not being dismissive and defensive...and would actually like to have an objective discussion, I'm happy to entertain.

I believe we agree that ideally, dynamic forces are concentrated at the rear axle like a 5th wheel where they are best managed. Bumper pulled trailers are different in that there's overhung and leveraged forces on the tow vehicle. A WD hitch is all about helping manage those overhung forces.

Again, there's no argument from me in regards to the advantages of a PPP type hitch in the horizontal plane which governs sway. This is proven and there's significant geometric advantages here as it locates the virtual pivot closer to the rear axle for sway forces.

On the vertical plane, which impacts porpoising, the geometry is worse than a standard hitch. The geometry is simple to compare. A PPP type hitch increases the overhang distance to the rear axle by approximately an additional foot, giving trailer forces additional leverage on the tow vehicle. Because it moves the physical pivot farther away from the rear axle for tongue forces.

What a PPP type hitch does to improve sway, it worsens for porpoising.

There's the additional factor that it adds another 100lbs. Much of this weight is localized to the rear axle even after WD.

Picture may help

[ROBERT CROSS]

^
Where in the drawing is it presented that the PP is now at the TV rear axle and not the ball...POOF goes the 'theory'.

It's just PPP after all. 🤔

Bob

[pteck]

Originally Posted by ROBERT CROSS

^
Where in the drawing is it presented that the PP is now at the TV rear axle and not the ball...POOF goes the 'theory'.

It's just PPP after all. ��

Bob

Shows how much you care to actually read because it's acknowledged if you even bothered looking past the picture which is focused on vertical forces, but cheers anyways.

I know there are others here that actually want to collaborate and discuss. Don't get me wrong, PPPs are brilliant hitches and magic for the right rigs. As with anything, there's trades. Going in eyes wide open and informed is the best way to make a decision.

[ROBERT CROSS]

Originally Posted by pteck

Shows how much you care to actually read because it's acknowledged if you even bothered looking past the picture which is focused on vertical forces, but cheers anyways.

I know there are others here that actually want to collaborate and discuss. Don't get me wrong, PPPs are brilliant hitches and magic for the right rigs. As with anything, there's trades. Going in eyes wide open and informed is the best way to make a decision.

I just feel bad that I don't have the intellect to explain it to you. 🥲

All I know is what I know.
Porpoising has little to do with a PPP hitch. They are no more susceptible to it than any other type of hitch. It's all about balance, loading, and proper weight distribution.
POI, most porpoising is caused by harmonic undulations in the road surface.

Bob
🇺🇸

[Silvr_Bullet]

In the diagram I do not see any downward reference applied force from the PPP towers. That should count for something.

[Bcc75]

25’ International RB towed with F250. Equalizer with 1000lb bars. 2500 miles of towing so far and no issues, no popped rivets. No sway whatsoever. I run the stock Goodyear Endurance tires at 65lbs psi with the trailer loaded. I have found that this tire pressure is ideal for ride quality eases stress on the trailer. For the money, the Equalizer can’t be beat IMO.

[pteck]

Originally Posted by Silvr_Bullet

In the diagram I do not see any downward reference applied force from the PPP towers. That should count for something.

Correct and the point wasn't to identify the WD tension force. As that is equally something all WD hitches are generally capable of.

The point is that dynamic vertical forces at the trailer tongue are acting on an extended lever arm relative to standard WD hitches.

Hence why it exacerbates porpoising. Forces and resulting harmonics that are harder for the front or rear suspension dampers to manage, as they prorogate and seesaw across axles, including the trailer axles.

[ROBERT CROSS]

Uncle

Bob
🇺🇸

[Silvr_Bullet]

Originally Posted by pteck

If you're not being dismissive and defensive...and would actually like to have an objective discussion, I'm happy to entertain.

I believe we agree that ideally, dynamic forces are concentrated at the rear axle like a 5th wheel where they are best managed. Bumper pulled trailers are different in that there's overhung and leveraged forces on the tow vehicle. A WD hitch is all about helping manage those overhung forces.

Again, there's no argument from me in regards to the advantages of a PPP type hitch in the horizontal plane which governs sway. This is proven and there's significant geometric advantages here as it locates the virtual pivot closer to the rear axle for sway forces.

On the vertical plane, which impacts porpoising, the geometry is worse than a standard hitch. The geometry is simple to compare. A PPP type hitch increases the overhang distance to the rear axle by approximately an additional foot, giving trailer forces additional leverage on the tow vehicle. Because it moves the physical pivot farther away from the rear axle for tongue forces.

What a PPP type hitch does to improve sway, it worsens for porpoising.

There's the additional factor that it adds another 100lbs. Much of this weight is localized to the rear axle even after WD.

Picture may help
Attachment 399787

Please cite the ‘sources’ of the conclusion that PPP type hitches “worsens porpoising “ more so than other weight distribution hitches. Also where did you obtain the diagram you posted. BTW Hensley states that it’s hitch operates similar to a fifth wheel. I can post Hensley’s video for that citation or you can view it at their website. I am interested in fact based information about weight distribution hitches.

[ROBERT CROSS]

Originally Posted by Silvr_Bullet

Please cite the ‘sources’ of the conclusion that PPP type hitches “worsens porpoising “ more so than other weight distribution hitches. Also where did you obtain the diagram you posted. BTW Hensley states that it’s hitch operates similar to a fifth wheel. I can post Hensley’s video for that citation or you can view it at their website. I am interested in fact based information about weight distribution hitches.

With some it's just the fact that the ppp design extends the tongue length which, on its own can negatively affect towing. That does leave out the fact the design does move the pivot point from the trailer ball to the tow vehicle rear axle.
Any porpoising we have had has been corrected by proper weight distribution and TV & trailer loading.

Disclaimer...I noe nutt'n and have only used the Hensley since 2007.

Bob
🇺🇸

Oh my it's so far away, are we porpoising yet? No

[mgblake13]

Originally Posted by Air Cruiser

mgblake13 — We had not heard of a “genyhitch” before, so thanks for that info — will definitely research those.

I am quite happy with my equalizer/GEN-Y hitch combo. I believe it makes for a smoother ride.

The downside of adding it initially was the additional expense. A continuing downside is the weight. It’s heavy. I use a flat garden cart to wheel it out of my garage to my truck because it weighs just over 100lbs. Fortunately the garden cart is exactly the right height so I just have to move it horizontally.

[Bill M.]

Our Reese Dual Cam sure seems to do a great job. I run 750 bars on the 25’ and 1000 for the 32’. Lots of people run and like the Equalizer. Bob Cross is correct that setup is the key factor for a hitch.

[jcl]

Originally Posted by ROBERT CROSS

With some it's just the fact that the ppp design extends the tongue length which, on its own can negatively affect towing. That does leave out the fact the design does move the pivot point from the trailer ball to the tow vehicle rear axle.

I fully get that. I like the idea of a four bar linkage to create a virtual pivot point. It seems to me an elegant engineering solution. But that refers only to the horizontal plane, not the vertical plane. So, sway (side to side) would be addressed/mitigated, but there is no projection of the pivot point in the vertical plane.

This isn’t to say that porpoising would happen, just that the PPP design doesn’t reduce it in the same way that it addresses side to side forces, and the increased longitudinal offset with the PPP design may impact the critical speed at which roadway undulations initiate porpoising.

I would choose the PPP myself. I would adjust WD tension to manage any tendency to porpoise. If I couldn’t resolve it that way, I would adjust my travel speed. But I wouldn’t expect the PPP design to better manage porpoising than a non PPP WD hitch.

[jcl]

Originally Posted by Silvr_Bullet

Please cite the ‘sources’ of the conclusion that PPP type hitches “worsens porpoising “ more so than other weight distribution hitches. Also where did you obtain the diagram you posted. BTW Hensley states that it’s hitch operates similar to a fifth wheel. I can post Hensley’s video for that citation or you can view it at their website. I am interested in fact based information about weight distribution hitches.

See above. It is based on engineering principles.

The fifth wheel reference refers to side to side, not to vertical forces.

[Silvr_Bullet]

Originally Posted by jcl

See above. It is based on engineering principles.



The fifth wheel reference refers to side to side, not to vertical forces.

Thanks! It’s my understanding that what makes a fifth wheel stable is the pivot / weight over the rear wheels as the PPP WDH mimic. But I thought the discussion is that PPP is more prone to proposing. I am waiting for concrete answers that’s the case.

[ROBERT CROSS]

Originally Posted by jcl

See above. It is based on engineering principles.

The fifth wheel reference refers to side to side, not to vertical forces.

No the reference is to a PROPER lash-up.
A PPP hitch can't 'worsen' something that isn't happening, nor will it cause it on a proper lash-up.
Most common cause...road conditions, not operator error.
Bob
🇺🇸

[jcl]

Originally Posted by Silvr_Bullet

Thanks! It’s my understanding that what makes a fifth wheel stable is the pivot / weight over the rear wheels as the PPP WDH mimic. But I thought the discussion is that PPP is more prone to proposing. I am waiting for concrete answers that’s the case.

What makes a 5th wheel configuration stable is two things.

1) the tongue weight is applied over top of the tow vehicle rear axle, or close to it.

2) the lateral forces from the trailer are applied near the rear tires of the tow vehicle, which are what resist the lateral forces.

With an overhung rear hitch, the lateral forces are applied at the hitch ball, so there is a lever arm from there to the rear tire contact patch. The PPP design projects this forward to a point near the rear tires of the tow vehicle. This addresses the propensity to sway side to side. That mimics point 2, above.

The PPP does not project the pivot point forward vertically. Correct WD setup helps here, and will reduce the tendency to porpoise (vertical oscillation) for both PPP and non PPP WD hitches.

The proposition under discussion is whether the greater longitudinal offset of the PPP over other WD designs increases that tendency to porpoise. Physics says it will. That doesn’t mean it will be a problem, as adjusting WD tension may overcome the longer lever arm. That may be what Bob is referring to IMO.

[jcl]

Originally Posted by ROBERT CROSS

No the reference is to a PROPER lash-up.
A PPP hitch can't 'worsen' something that isn't happening, nor will it cause it on a proper lash-up.
Most common cause...road conditions, not operator error.
Bob
����

I think that you are failing to distinguish between the horizontal and vertical planes. The four bar linkage in a PPP design is configured to address one of these, the horizontal plane, and by all accounts does so very well.

Porpoising can happen with any overhung hitch. I think we agree that it is initiated by road undulations, in combination with travel speed. The PPP design is not immune. It may be more prone to porpoising due to the longer offset. You apparently are able to address that by adjusting WD tension. That’s great. But you can’t deny that there is a longer lever arm.