Panhard drop bracket option?

[CharlieS]

I feel like this is good theory but more applicable to extreme suspension build outs like on rock buggies, desert racing trucks, extreme jeeps, and things like that. Without measuring it, and knowing how long the panhard is on the 200, I doubt a couple of inches of lift or additional down travel is going to have that much side to side movement in the range of the arc it will travel. IMHO, YMMV, etc.

 

[bloc]

I can understand the reasons for wanting to minimize the “wag” and how the geometry of the panhard means having it horizontal when the truck is at “normal” ride height does this. Great thread here. I just have never noticed any “wag” and I have 30mm spacers on top of my rear 2721s.

Also, I don’t see how the bump stops could miss the targets at full up travel. The panhard is a fixed radius so the bump stop has to hit the target. What am I missing?

When you move the frame end of the panhard down, if the suspension cycles up to its original upper limit the arc starts to pull the axle toward the frame end of the panhard more than stock. Basically with a lower frame end the sagitta increases as you move to the original bump stop position. Obviously this will depend on the length of the panhard and how much we relocate the end.. and as mentioned an extended panhard to return the axle to center with a significant lift will have the same problem the other direction.

Just saying there isn’t a perfect solution when we start modifying ride height.

I feel like this is good theory but more applicable to extreme suspension build outs like on rock buggies, desert racing trucks, extreme jeeps, and things like that. Without measuring it, and knowing how long the panhard is on the 200, I doubt a couple of inches of lift or additional down travel is going to have that much side to side movement in the range of the arc it will travel. IMHO, YMMV, etc.

I dunno.. I definitely feel it. Bridge expansion joints are the classic cause of the type of suspension movement that makes it obvious to me. And when loaded for a trip it is less obvious, just as @montegofd3s noted.

 

[Toyoland66]

@eimkeith makes relocation brackets for other platforms not sure if he’s considered the 200

 

[jkeithw]

@eimkeith makes relocation brackets for other platforms not sure if he’s considered the 200

in development, actually. (but it's a lift bracket - I'm all about raising that roll center)

 

[mdh384]

in development, actually. (but it's a lift bracket - I'm all about raising that roll center)

I am glad to hear that a solution is in the works. Are you working on a weld-on or bolt-on bracket?

Edit - I see you're in NC. My LC200 is currently located Durham for the next few years, in the possession of family and will not be getting driven much. If you need a test mule for development I'd be happy to offer up my truck.

 

[jkeithw]

I am glad to hear that a solution is in the works. Are you working on a weld-on or bolt-on bracket?

Thanks!

All my PCK®s are weld-on (like the factory mount) and selectable for height (since that changes according to load level).

- in addition to the 4Runner/FJC/GX models and the 80-series, I've also just released the PCK® for the first-gen Sequoia, am now finalizing the 200-series (a lot of requests from my resellers for these), and the 100 is in progress as well (several client requests lately for this one).

 

[TeCKis300]

Even stock, the panhard sagitta is noticeable on bigger bumps. It's part of the characteristic of this type of suspension architecture vs say rear IFS. It was noticeable to me on the stock LX lower profile tires. Once going to larger profile tires, the added sidewalls seemed to help absorb some part of the lateral displacement. Same with carrying more load. Inertial ballast that pushes other parts of the system to absorb the lateral motion.

Those dynamics on an LC with stock 18" wheels, perhaps modded with larger tires still, with added armor, and stiffer racier lift suspensions, could minimize some of the perceivable affects in gentle to moderate driving. Glad to hear there's venders developing this still. Just as front UCAs compensate geometry for higher lifts, the panhard relocation will be a major win for the rear.

Prioritizing suspension geometry is why I've only sensor lifted my rear .75". The LX at speed will drop ~1" which puts the suspension back into its sweet spot for higher speed handling. Most of my choices has really been to maintain suspension performance and towing safety as geometry impacts get greatly magnified, perhaps becoming safety issues hauling that type of load. I really wouldn't want rear lateral displacement setting up a trailer sway event.

Maybe interesting, trucks designed to carry load use leaf spring suspension. As archaic as it can be for suspension control, and it has its own compromises, it doesn't have sagitta issues links can have. And can be more easily modified to extremes.

 

[bloc]

Even stock, the panhard sagitta is noticeable on bigger bumps. It's part of the characteristic of this type of suspension architecture vs say rear IFS. It was noticeable to me on the stock LX lower profile tires. Once going to larger profile tires, the added sidewalls seemed to help absorb some part of the lateral displacement. Same with carrying more load. Inertial ballast that pushes other parts of the system to absorb the lateral motion.

Those dynamics on an LC with stock 18" wheels, perhaps modded with larger tires still, with added armor, and stiffer racier lift suspensions, could minimize some of the perceivable affects in gentle to moderate driving. Glad to hear there's venders developing this still. Just as front UCAs compensate geometry for higher lifts, the panhard relocation will be a major win for the rear.

Prioritizing suspension geometry is why I've only sensor lifted my rear .75". The LX at speed will drop ~1" which puts the suspension back into its sweet spot for higher speed handling. Most of my choices has really been to maintain suspension performance and towing safety as geometry impacts get greatly magnified, perhaps becoming safety issues hauling that type of load. I really wouldn't want rear lateral displacement setting up a trailer sway event.

Maybe interesting, trucks designed to carry load use leaf spring suspension. As archaic as it can be for suspension control, and it has its own compromises, it doesn't have sagitta issues links can have. And can be more easily modified to extremes.

It actually seems like the 1” drop at speed might put the panhard in a more beneficial position to reduce sagitta, specifically when you’d want it. Whoever mentioned high speed stability (then deleted their post apparently) nailed it.. that is the thing that bothers me.

You are totally correct in that there is some movement on a stock LC, and I interpreted this as toyota having to compromise between total travel for off-road and acceptable on-road behavior. Plus loading the rear might reduce sagitta exactly when you’d have all the extra weight back there and need more stability. So in effect planning ahead. Lots of speculation here on my part, I’m aware.

The ironic thing is that this is all caused by the need for a lot of travel. There are other axle location schemes like a watts link that can work great, but would struggle with packaging and how much travel we need out of the rear. I had an old fb rx7 which came with watts link and those often deal with the exact opposite of our issue, when they lower the vehicle a significant amount it starts to do odd things to the rear. But within the normal range of travel of a sports car it avoids sagitta almost completely.

 

[montegofd3s]

now finalizing the 200-series (a lot of requests from my resellers for these), and the 100 is in progress as well (several client requests lately for this one).

This is great news! Thank you for tackling this, and I would greatly appreciate if you could let us know when they are ready for production. I know I will be getting in line immediately to hand over some money.

 

[OwnerCS]

It actually seems like the 1” drop at speed might put the panhard in a more beneficial position to reduce sagitta, specifically when you’d want it. Whoever mentioned high speed stability (then deleted their post apparently) nailed it.. that is the thing that bothers me.

You are totally correct in that there is some movement on a stock LC, and I interpreted this as toyota having to compromise between total travel for off-road and acceptable on-road behavior. Plus loading the rear might reduce sagitta exactly when you’d have all the extra weight back there and need more stability. So in effect planning ahead. Lots of speculation here on my part, I’m aware.

The ironic thing is that this is all caused by the need for a lot of travel. There are other axle location schemes like a watts link that can work great, but would struggle with packaging and how much travel we need out of the rear. I had an old fb rx7 which came with watts link and those often deal with the exact opposite of our issue, when they lower the vehicle a significant amount it starts to do odd things to the rear. But within the normal range of travel of a sports car it avoids sagitta almost completely.

It was me. I shouldn't have deleted the post. I think this thread is more scientifically grounded than times I've listed the benefits of running a PCK kit. Yes, I'm an advocate of PCKs. I started learning about the kit benefits from my 4Runner friends with extreme lifts. My 100 series build and use case are different than most. I'm lifted 3+ inches in the rear with 2" in the front with the heaviest springs available. I often run over GVWR due to a metal storage box full of tools, parts, jacks, recovery gear. My rig is strictly for off-road use. It is driven less than 5,000 miles a year. It is driven very fast on the highway between off-road destinations.

Benefits:

1) Improved stability during high-speed highway driving over overpasses, bumps in the road, and railroad tracks.
2) Improved handling while driving high speed on paved switchback-type roads. The suspension allows it to handle more like a sports truck than a big lumbering SUV.
3) Improvided control when driving off-road at higher speeds over washouts and dips. Near Raptor trail jumping off-road behavior.

I've been familiar with sagitta and like to show the video to people who will listen. I come from a lowered sports car world where we have the sagitta problem from incorrect Panhard angles from being lowered instead of lifted. I also have two lowered cars with Scott-Russell link rear suspensions (oh yea the weird ones) and enjoy them.

It looks like you guys are on the right track. You seem like a fun group. I would love to talk to you guys someday about suspensions and how to optimize performance. I plan to be in Silverton CO during the last week of July should we have that opportunity.

Cheers!

 

[bloc]

Random thought today..

A panhard relocation bracket with multiple location options could be combined with an adjustable panhard to dial in panhard angle for different loads.

For instance if someone is heavily loaded for a trip and that weight causes 2” of suspension sag, it wouldn’t be very difficult to move that end to flatten the bar. But move it back and keep better manners for unloaded daily driving.

 

[jkeithw]

Random thought today..

A panhard relocation bracket with multiple location options could be combined with an adjustable panhard to dial in panhard angle for different loads.

For instance if someone is heavily loaded for a trip and that weight causes 2” of suspension sag, it wouldn’t be very difficult to move that end to flatten the bar. But move it back and keep better manners for unloaded daily driving.

right! - but an adjustable panhard wouldn't be required, necessarily (since you're re-leveling each time you adjust, and the holes are vertical in orientation).

 

[kcjaz]

right! - but an adjustable panhard wouldn't be required, necessarily (since you're re-leveling each time you adjust, and the holes are vertical in orientation).

But the adjustable panhard would allow you to adjust the axle position side to side so you could align the bump stops at full up travel.

As long as we are at it, we should add actuators…

 

[afgman786]

An AHC type switch for the panhard to click thru 3 stages? Unloaded, mild, heavy?

 

[AnyMal]

What it really needs is a watts link fitment.
Perfect for AHC.

 

[TeCKis300]

What it really needs is a watts link fitment.
Perfect for AHC.

Academically, okay, an interesting solution. In practice, watts setups are more complex with more links and pivots (read: reliability and durability). For an off-roader, they create low hanging suspension components presenting clearance issues to the ground at full stuff.

There's really nothing wrong with a panhard bar. On the contrary, it's part of a premium 5-link setup that's generally considered a robust and and high performing for a solid rear axle. You'll find them used on a whole host of modern high performance vehicles. From RAM TRX, to the new Raptor R that now uses 5-link over the leaf spring config of the previous 2 generation Raptors.

Only thing "better" is a triangulated 4-link for real dedicated off-roaders. Yet they're not as accurate laterally for street use with packaging challenges so it's strictly a rock crawler / race car configuration.

5-links are great. It's when we modify them that creates compromises unless paying attention to geometries and details.

 

[AnyMal]

Academically, okay, an interesting solution. In practice, watts setups are more complex with more links and pivots (read: reliability and durability). For an off-roader, they create low hanging suspension components presenting clearance issues to the ground at full stuff.

There's really nothing wrong with a panhard bar. On the contrary, it's part of a premium 5-link setup that's generally considered a robust and and high performing for a solid rear axle. You'll find them used on a whole host of modern high performance vehicles. From RAM TRX, to the new Raptor R that now uses 5-link over the leaf spring config of the previous 2 generation Raptors.

Only thing "better" is a triangulated 4-link for real dedicated off-roaders. Yet they're not as accurate laterally for street use with packaging challenges so it's strictly a rock crawler / race car configuration.

5-links are great. It's when we modify them that creates compromises unless paying attention to geometries and details.

Super interesting with the more linear travel yeah.
Ive been wondering how durable this sort of setup would be myself, it seems like its mostly in the slamming and airbagged show trucks.
You are never the first to think of something so in this case i know there must be several good reasons why we dont see them implemented industry wide.

Speaking of our 5 link, do you know why is the panhard angle so vertical at mid travel (or should i say at ride height) when all the technical recommendations are for parallel? Ive spoken about my wag some time ago and brought up the watts link then as well but im wondering how much influence the panhard can have on linear rear axle articulation if any. Not like i am pursuing it seriously or anything but my curiosity is piqued.

 

[eurosonic]

I added one to my truck.
Helped out quite a bit. No more butt wiggle

 

[kcjaz]

I added one to my truck.
Helped out quite a bit. No more butt wiggle

View attachment 2849407

Got a pic with the panhard installed?

 

[eurosonic]

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