80 series caster problem (1 Viewer)

[stvrn6]

I purchased this project 1997 land cruiser that i just finished working on. I took it on the highway and its very unstable. The steering seems to very jerky. The steering wheel is also not straight either its a few degrees to the right to go straight as well as has a ton of free play.
I'm running Eibach shocks with OME heavy springs front and rear due to extra load. i went to get an alignment to get a base line for my caster and its showing -2 left and -1.9 right. Do i get a 4 degree correction plat or 2? Im just asking since the 4+ correction is recommended for 4+ inch lift and im runnin 2-3 in lift. should i do bushings or plates?
edit: running 315s r17

 

[Nay]

Wow very long winded.
I run the landtank 4” lift plates and they work well and I agree that the design is preferred as it rotates the axle instead of just dropping the front.
I also run OEM Arms and I’m happy with them.
I also run some of the hardest trails out there and have posted on many videos of it.
I have also run 5” of lift and IMO it down right scary and very old school.
A more common theme today is a low lift with a big tire = a lower center of gravity and a more stable vehicle.
Yes that might mean some cutting is needed but make a safer vehicle.

Hey I post videos and anybody can make their judgements.

I see lots of poorly designed suspensions that lift front wheels, unload, and are generally floppy on lower lifts. Sad!

The key with the 80 is avoiding the temptation of travel over stability. If you don’t unbalance front to rear, it’s a stupid stable rig.

Which is why I disagree with the general design premise that has been advocated here forever - you add a bunch of weight and stiff linear springs biased to up travel and those dominoes will never, ever, stand back up .

Sort of like just picking caster on a solid front axle and ignoring the simple and commonly understood physics that a u-joint operating at an angle moves in an oval and if you have different oval paths at each end it’s going to vibrate.

We unsolve problems here so aggressively it’s just straight fascination to play along.

 

[mudgudgeon]

The key with the 80 is avoiding the temptation of travel over stability. If you don’t unbalance front to rear, it’s a stupid stable rig.

My 105 series had 2" spring lift, 5" shocks, shock mounts modified to retain full uptravel. 2⁰ caster correction. No front sway bar, rear sway bar in place.

Thing was super stable and predictable

 

[Nay]

My 105 series had 2" spring lift, 5" shocks, shock mounts modified to retain full uptravel. 2⁰ caster correction. No front sway bar, rear sway bar in place.

Thing was super stable and predictable

We can agree on no swaybars and optimizing suspension travel to the sweet spot of the spring travel. A willingness to relocate mounts including into the cabin changes things.

Stable, planted, and willing to climb anything as long as too much body weight isn’t in contact are hallmarks.

This is with the 4.5” Dobinson Flexi coils and 37’s, which really are too small.



This is 5.5” with the CVT coils and 38’s.



I’ve never thought to look for these terrible compromises about having a perfectly tuned suspension. The ocean of sheet metal and glass is another story that keeping the body low doesn’t really solve.

 

[Broski]

We can agree on no swaybars and optimizing suspension travel to the sweet spot of the spring travel. A willingness to relocate mounts including into the cabin changes things.

Stable, planted, and willing to climb anything as long as too much body weight isn’t in contact are hallmarks.

This is with the 4.5” Dobinson Flexi coils and 37’s, which really are too small.



This is 5.5” with the CVT coils and 38’s.



I’ve never thought to look for these terrible compromises about having a perfectly tuned suspension. The ocean of sheet metal and glass is another story that keeping the body low doesn’t really solve.

THE ROCK PILE
They should call that the ramp !

 

[Broski]

Not my video

 

[mudgudgeon]

THE ROCK PILE
They should call that the ramp !

Not exactly most people's use case.

If this is your primary goal, neither caster or driveline vibes matters much.

 

[Nay]

Not exactly most people's use case.

If this is your primary goal, neither caster or driveline vibes matters much.

I don’t trailer it, so 6 or 7 hours drives to cool places like Moab are in the cards. I could take it part time 4WD now that I don’t rely on it for winter use, but selectable AWD is damn useful for tight switchback trails we have in Colorado.

This baby needs 5.29’s and lockers. Talk about fun.

 

[Nay]

Not my video

So I’ve been watching the Stellar Built Rubicon vids with the Moscow Mule, exactly to this point where they took a 4th gen Runner down to the bare frame with no mounts and then built the travel up into the interior, notched the frame for front clearance of the suspension arms, and are running 42’s with dual cases. It’s so clean if you can do that kind of fab work.

I own a 4th gen on a couple inches of lift and 33’s (well it’s passed down to one of my sons), and the visibility out is terrible compared to an 80, but that project makes me want a 4th gen, minus the $50K entry fee. It’s such a lame stock platform and people are doing some exceptional builds with them.

This whole convo is like “well let’s see it on Soup Bowl”

This is good for perspective.

 

[Broski]

So I’ve been watching the Stellar Built Rubicon vids with the Moscow Mule, exactly to this point where they took a 4th gen Runner down to the bare frame with no mounts and then built the travel up into the interior, notched the frame for front clearance of the suspension arms, and are running 42’s with dual cases. It’s so clean if you can do that kind of fab work.

I own a 4th gen on a couple inches of lift and 33’s (well it’s passed down to one of my sons), and the visibility out is terrible compared to an 80, but that project makes me want a 4th gen, minus the $50K entry fee. It’s such a lame stock platform and people are doing some exceptional builds with them.

This whole convo is like “well let’s see it on Soup Bowl”

This is good for perspective.

Some nice Rigs !
I don't see a Green 80 on 38s
That's a bad A** trail Hats off to all the full bodyed rigs running it. More of a Buggy trail !

 

[Nay]

Some nice Rigs !
I don't see a Green 80 on 38s
That's a bad A** trail Hats off to all the full bodyed rigs running it. More of a Buggy trail !

There is no amount of tire to take an ocean of sheet metal and glass up Carnage.

We’ll be running some of the Montrose stuff like Die Tryin’ once I get my steering sh$t sorted now that I’m mostly on the Western Slope for wheeling. Will see how long my philosophy of 38’s are enough will last.

Front driveshaft still won’t vibrate on the way home . Rear…well that’s what spares are for.

Anyway if you want to watch Sherpa destroy their 4th gen this is good stuff.

 

[Broski]

There is no amount of tire to take an ocean of sheet metal and glass up Carnage.

I was looking for that perspective

 

[Nay]

I was looking for that perspective

None of this makes me want to intentionally design a crazy expensive a low lift with a vibrating driveline. Using a crowbar to bend out the rear PS quarter panel and replacing the Depo tail light again is another story.

 

[Broski]

None of this makes me want to intentionally design a crazy expensive a low lift with a vibrating driveline. Using a crowbar to bend out the rear PS quarter panel and replacing the Depo tail light again is another story.

That why I built my RQP projection
Except I prefer a piece of Hardwood.

 

[stvrn6]

Hey guys, installed panhard bracket from delta and was able to source some dobinson bolt on plates locally for cheap and the truck drives so much better, night and day. But now I have another question. When I went in for an alignment for my initial caster numbers i was running a different set of springs (eibach) but i since changed them to some heavier springs i bought some time ago for added weight. well i changed out the tie rods and draglinks so i took it back for an alignment and my new caster readings are 5 degrees. the OME springs are 2 in and the eibach are 3+in. How worries should i be about having 5 degrees vs 4?
front: ome 2850 rear : ome 2863. I found some 2864s on fb market place for cheap and was planning on getting those since ive added more weight since than.
I could source some 2850j and 2863j and or dobinsons heavy springs if it'll correct my caster.

 

[Broski]

Hey guys, installed panhard bracket from delta and was able to source some dobinson bolt on plates locally for cheap and the truck drives so much better, night and day. But now I have another question. When I went in for an alignment for my initial caster numbers i was running a different set of springs (eibach) but i since changed them to some heavier springs i bought some time ago for added weight. well i changed out the tie rods and draglinks so i took it back for an alignment and my new caster readings are 5 degrees. the OME springs are 2 in and the eibach are 3+in. How worries should i be about having 5 degrees vs 4?
front: ome 2850 rear : ome 2863. I found some 2864s on fb market place for cheap and was planning on getting those since ive added more weight since than.
I could source some 2850j and 2863j and or dobinsons heavy springs if it'll correct my caster.

How do you like the way it drives ? more Caster will make the steering feel heavier and the steering return to center faster.
IMO 5-6 degrees is fine and good for big tires. I set the caster to 6 degrees on my Buggy that's on 42s

 

[Nay]

The best way to avoid these concerns is to not pay money to have them measured - I haven’t had a shop alignment in 15 years. There’s nothing to align on a solid axle once pinion angle is correct except toe, which you can do yourself with a telescoping rod and then center the wheel with the relay rod.

 

[Broski]

The best way to avoid these concerns is to not pay money to have them measured - I haven’t had a shop alignment in 15 years. There’s nothing to align on a solid axle once pinion angle is correct except toe, which you can do yourself with a telescoping rod and then center the wheel with the relay rod.

Unhelpful at best

 

[Nay]

Unhelpful at best

What the point of measuring stuff you can’t change?

That’s what the medical system does and the primary outcome is just anxiety. If we started properly calling ‘caster plates’ “pinion angle plates” it would save this community a tremendous amount of pearl clutching.

When you have separate upper and lower adjustable front control arms like on a Jeep, nobody calls them “caster arms”. You just use them to properly adjust pinion and make minor adjustments to wheelbase. Then if you really want to spend $80 on a printout you can go get one.

I’ll be more helpful, here’s how you use a telescoping rod to set toe - make sure the front of the tire measurement at 9 o’clock is 1/8” less than the measurement from the rear at 3 o’clock. We have a wonderfully easy to use tierod and relay rod system and a bit of toe-in is what you want with big tires. Cuts down a lot of wandering due to your pinion angle. Get a shop alignment and keep toe at zero or with ‘in-spec’ toe out and enjoy the high speed float feeling.

 

[Broski]

What the point of measuring stuff you can’t change?

That’s what the medical system does and the primary outcome is just anxiety. If we started properly calling ‘caster plates’ “pinion angle plates” it would save this community a tremendous amount of pearl clutching.

When you have separate upper and lower adjustable front control arms like on a Jeep, nobody calls them “caster arms”. You just use them to properly adjust pinion and make minor adjustments to wheelbase. Then if you really want to spend $80 on a printout you can go get one.

I’ll be more helpful, here’s how you use a telescoping rod to set toe - make sure the front of the tire measurement at 9 o’clock is 1/8” less than the measurement from the rear at 3 o’clock. We have a wonderfully easy to use tierod and relay rod system and a bit of toe-in is what you want with big tires. Cuts down a lot of wandering due to your pinion angle. Get a shop alignment and keep toe at zero or with ‘in-spec’ toe out and enjoy the high speed float feeling.

I think you missed the point.
And castor and drivability are connected.
In a perfect world one would do a cut and turn then you could have proper pinion angle and proper caster at the same time. but that's not the question that was presented.
Per the FSM toe should be set at 2mm and yes I do my own at home

 

[Nay]

I think you missed the point.
And castor and drivability are connected.
In a perfect world one would do a cut and turn then you could have proper pinion angle and proper caster at the same time. but that's not the question that was presented.
Per the FSM toe should be set at 2mm and yes I do my own at home

I redirected the point

I’m pretty sure very few people here has ever driven a rig where caster made it undriveable. Caster isn’t an isolated variable that has to be in a black and white spec.

A Jeep XJ, for example has 7 degrees as optimal factory spec. So why not 2-4? For starters, that vehicle doesn’t have radius arms and it also comes factory with a y-linkage steering setup (relay is attached directly to tierod). That means toe changes with suspension compression and there is terrible vulnerability to bump steer. We don’t deal with either of those things.

I converted an XJ to a long arm radius setup with a custom Dana 44 axle and we deliberately set caster at 2 degrees so avoid quick/touchy steering on a big lift at speed. This worked perfectly 5 degrees under factory spec in conjunction with a crossover steering linkage (like what we do with high steer).

Early on, I had a set of customer front coils built and then provided 9” of lift instead of the 6” we spec’d. The truck drove in a Z down the highway, it wasn’t steering feel or touch, the caster situation was so bad in conjunction with the factory steering and control arm linkage that it was unable to drive straight.

Given that you can convert the front 80 series driveshaft to double cardan, which uniquely to the 80 lowers the pinion and increases caster to offset up a 4” lift, you need to get up in the range I have before ‘driveability’ relative to other platforms is rearing its head.

I also take videos. Look at this terrible time I’m having with driveability.



And before we start arguing that caster isn’t about driving in a straight line, here’s canyon driving. Pay attention to the speed signs in the corners vs. the speedo as I run down that Subaru. 38” tires, no sway bars. My speedo is corrected so that’s accurate. Just in case we’re having conceptual interpretation problems, in order to take these vids I’m driving with one hand.