Here's a couple old posts, one with a picture that might help explain. More people with larger lifts should get the panhard drop correction. Much like UCAs for lifts over 2" on the front end, the drop bracket would be that correction for the rear axle.
Panhard drop bracket option? (3 Viewers)
- Thread starter montegofd3s
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Here's a couple old posts, one with a picture that might help explain. More people with larger lifts should get the panhard drop correction. Much like UCAs for lifts over 2" on the front end, the drop bracket would be that correction for the rear axle.
Problem is thrust angle cannot be reliable measured in the LX because the rear will dump when off. I have another visit this wed and need to seriously bribe some guys to do multiple rollbacks with the truck running somehow. They have a true 4 wheel ramp with floating rear pads too. And will even let me in the bay to play with my panhard (giggity).
Got everything as neutral as possible like i asked, and im aiming for 4+ caster on both, but there is something wrong with my driver side...
Frame warp, welds, something. And its not weighted down because I'm not siting in it.
Also look how the rear "toe" changed for no reason.
There was another poster who mentioned their front left never wearing right i think in my bitch thread too? I seem to have the same issue.
Its the first wheel to always want to break traction and ABS first.
AHC is a real pain sometimes.
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Thrust angle is impacted and why i have adjustable bar back there. Not because youre wrong, but because its skewed relative to the front.
The panhard will pull the rear axle out of square by the nature of its swing against the fixed 4 link, creating tension at the pinion.
Its just a side effect of the amount of articulation back there, not a design flaw.
Thats what solved my driveline wobble in that laborious thread i made.
Why ive always wanted a parallel watts link... Someday maybe.
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Not sure how much you've lifted your rear? Sure seems like you're in need of a panhard drop bracket.
An adjustable bar may only solve part of the issue. In a lifted position, it's at a steeper angle, and more sensitive to ride height changes like from perhaps AHC. When the panhard is at the stock angle, it won't change thrust angle appreciable.
IMO, you're blaming AHC for a number of things you've now changed up. It all works as a system and there's compromises to geometry when outside of it. I personally wouldn't bother with 4+ degrees caster either. Mid to high 3s is fine if offsets are reasonable.
TLC2013
SILVER Star
Those are some good numbers but yeah that rear toe reading seems abnormal. I always try and shoot for a fraction more caster on the passenger side to account for road crown. That is interesting how your thrust angle is at -.30. I do wonder how the system measures the "before" and "actual". I have seen my thrust angle fluctuate from -.15 all the way to -.30 once the alignment was completed. It has got to be a system anomaly as once the tech completes the alignment they hardly ever take the time to put the truck back on the rack to double check their numbers. The next alignment I got after seeing the -.30 thrust angle only registered -.15 degrees
I dont recall but at least 1" in the rear. And yes, i do have some intermittent wobble again since the preload on the rears.
Thats because of the added resistance to the highway speed drop back there from taller coils, its not where i had eyeballed it on the first fix anymore. And cannot be measured unless youre on a dyno, because AHC is difficult to mod correctly. No hate. Just normal musings of the system.
Totally not blaming AHC, its just a pain to do a true 4 wheel scan with it while its off. I could pull fuses though.
Just saying its more complicated than the LC. I still like it, most days...
.I do need the bracket, but I dont know how to weld.
Also my friend, you need to drive a 16+ on 21s on a TX Interstate at 85MPH before judging my caster and offset choices. LOL
Death mobile levels of instability.
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Those are some good numbers but yeah that rear toe reading seems abnormal. I always try and shoot for a fraction more caster on the passenger side to account for road crown. That is interesting how your thrust angle is at -.30. I do wonder how the system measures the "before" and "actual". I have seen my thrust angle fluctuate from -.15 all the way to -.30 once the alignment was completed. It has got to be a system anomaly as once the tech completes the alignment they hardly ever take the time to put the truck back on the rack to double check their numbers. The next alignment I got after seeing the -.30 thrust angle only registered -.15 degrees
Good numbers... yeah I hope!
Took me 4 attempts though to finally find 1) a brand new top of the line hunter rack 2) a tech that gave a s***.
TLC2013
SILVER Star
Very cool. I say tip the guy who gives a hoot. I have had good luck with this tactic and have been able to give the tech who performs the alignment my specific numbers. Generally I get what I want or close to it. This last alignment was a nightmare. He iniatially started trying to adjust caster and camber with the UCA!?!. I stopped him and had to point him toward the LCA bolts. I should have asked my tip back lol. But in the end he got me more or less what I wanted. With maybe a little too much toe in on my driver side so I am closely monitoring for any uneven wear. The unlimited/ lifetime alignment deals are well worth it especially if you get a shop that is open to hearing from you on specifics.
They always find 20s in whatever open shirt pockets theyre wearing. And on the drivers seat...
I might tape a hundred dollar bill on the panhard next time though. LOLOL
TLC2013
SILVER Star
Lol good one. $20's ?!? Must be the Lexus tax haha, I am holding strong at $10 for my Toyota lol.
Thats plenty for a highlander!
kcjaz
SILVER Star
I will preface what I'm about to say with, I don't really know what I'm talking about...
So I can see where if, the rear wheels are perpendicular to the rear axle and the axle itself is not parallel to the front axle that power to the rear wheels would generate a "thrust" not in alignment with where the front wheels are trying to go. Same thing if the front and rear axles were parallel but the rear wheels were not aligned to be perpendicular with the rear axle. You can look at this picture and see this:
However, there nothing adjustable on the rear axle of our 200s to adjust thrust angle. Whatever it is, is how your truck was built or how you have bent something. The side to side motion of the rear axle (sagitta) doesn't change the axle angle relative to the centerline of the vehicle. So, if the rear axle is perpendicular to the vehicle centerline but the suspension lift has caused the axle to be more driver's side compared to neutral, the front and rear wheel tracks are off set but there is no actual "thrust" misalignment. The "butt wiggle" isn't related to thrust angle and panhard brackets and/or adjustable panhards won't address a thrust angle issue. Or, I really just don't understand something here, which is possible and maybe even likely.
I wonder what the 4 wheel alignment machines are really measuring for thrust angle and how, once measured, it would ever change outside of the +/- accuracy of the measurement.
So I can see where if, the rear wheels are perpendicular to the rear axle and the axle itself is not parallel to the front axle that power to the rear wheels would generate a "thrust" not in alignment with where the front wheels are trying to go. Same thing if the front and rear axles were parallel but the rear wheels were not aligned to be perpendicular with the rear axle. You can look at this picture and see this:
However, there nothing adjustable on the rear axle of our 200s to adjust thrust angle. Whatever it is, is how your truck was built or how you have bent something. The side to side motion of the rear axle (sagitta) doesn't change the axle angle relative to the centerline of the vehicle. So, if the rear axle is perpendicular to the vehicle centerline but the suspension lift has caused the axle to be more driver's side compared to neutral, the front and rear wheel tracks are off set but there is no actual "thrust" misalignment. The "butt wiggle" isn't related to thrust angle and panhard brackets and/or adjustable panhards won't address a thrust angle issue. Or, I really just don't understand something here, which is possible and maybe even likely.
I wonder what the 4 wheel alignment machines are really measuring for thrust angle and how, once measured, it would ever change outside of the +/- accuracy of the measurement.
Yes and No. And im no expert at all. I left my ego at the door a long time ago here and always learning.
With a lift being a big caveat, its the overall "play" in the system that will cause it. Not just a left right centering.
Its when lifted, the frame link and axle link are not in plane anymore. One being further than the other.
And in the case of AHC, there not being slip yoked trailing arms or something and being inherently induced by its own lift mechanism.
Thats why the AHC speed parameters are so aggressive. In a perfect world, there would be hydraulic rams in the rear 4 link, linked to the shock height changes, perfectly synched to the lift height.
There is indeed a lot of play in the articulation regardless, which is why i can single handedly adjust my panhard using an adjustable wrench with just the pumpkin on a floor jack and the 2 front wheels still on the ground.
If the 4 link bushings were really that tight and did not shift at all, i would not have the physical strength the recenter anything by hand.
But I can, and thats why the 5th link exists, the axle would be floating otherwise and do all sorts of bad stuff side to side when one wheel is lifted.
Nevermind both side parallel links having competing swing arcs in single sided compression.
I brought my shop a box of donuts when they squeezed me in before a long trip.
jkeithw
Supporting Vendor
I see "panhard drop bracket" a lot in this thread recently - you should never drop the panhard, you should raise it. (Just FYI)
also, thrust angle (and any alignment, FWIW) is based on the rear axle position.
also, thrust angle (and any alignment, FWIW) is based on the rear axle position.
kcjaz
SILVER Star
For those who have installed the panhard “lift” bracket, have you removed/installed rear springs with the bracket installed? Just wondering if the spring would have to come out the front side of the axle which looks like that would require rear shock removal.
I'm running the Ironman 2" lift. Is a 2" enough to need the bracket to re align things or is it only needed for a higher lift?
Thanks you just summed up what I was trying to say. Unless the panhard bracket changes the direction the wheels point (I don’t think so) I don’t understand why shifting the axle and thus both wheels left or right would affect the thrust angle. All wheels are pointing forward, they’re just offset.
A10Driver
SILVER Star
Depending on the push it can misalign the axle a bit, as much as the suspension allows. The panhard does not attach to the middle of the axle, therefore any pushing or pulling will create some misalignment
A10Driver
SILVER Star
There are multiple holes, yes it will work for a 2". I have a little over 3" and used the top hole.
