Even more reason to run aftermarket arms with a three inch lift.
Another way to correct caster than plates, bushings or bearings??? 80 series (1 Viewer)
- Thread starter GW Nugget
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thanks for the trigonometry lesson courtesy of @Pin_Head
Years ago when I did a cut and turn, I calculated caster correction needed to be 1.7* per 1inch lift, at the time everyone insisted it was 1* per inch.
I suspected the change was not linear, but Trig is not my strongest point, so I didn't know how to calculate it out fully.
1.74 per inch is close enough for our needs and I corrected pinheads post at that time to correct for out trucks construction.
If you correct for caster beyond 4" of lift with arms or frame brackets you will have drive line angles that will cause severe vibrations.
The only way to maintain AWD and factory caster without vibrations is to do the frame drop and a cut and turn. Since a cut and turn has the same limitations as caster plates you would basically equate that to compensating for 4" of the lift and make the rest up with the frame drop. But you would still need to be conscience of pinion angles to combat drive line vibrations.
Or go part time. Which is ok provided you don't need H4 for any length of time.
If you correct for caster beyond 4" of lift with arms or frame brackets you will have drive line angles that will cause severe vibrations.
The only way to maintain AWD and factory caster without vibrations is to do the frame drop and a cut and turn. Since a cut and turn has the same limitations as caster plates you would basically equate that to compensating for 4" of the lift and make the rest up with the frame drop. But you would still need to be conscience of pinion angles to combat drive line vibrations.
Or go part time. Which is ok provided you don't need H4 for any length of time.
- Thread starter
- #24
Do you remember what thread that was so I can reference it?
I’m runnng j springs with 30mm spacer up front. Caster is corrected with Slee arms, I use to run Slee caster plates I which put the truck at 2.1 degrees just within stock. Radflos are made for 6 inch lift plenty of flex no clearance issues, with plates my tie rod use to contact the stock arms, since going to the slee arms I no longer contact tierod and truck drives even tighter
Sure, but if you're going the cut and turn route, you need @Pin_Head fuzzy feeling of ethical propriety, and be aware that tie rods will clash with radius arms before you fix caster at 4"of lift, unless tie rod is shifted to the front. Then you loose correct Ackerman steering geometry.
BTDT with cut and turn, and I think custom radius arms are a far better solution to maintain geometry.
4" lift opens a whole can of worms in the front end. Any solution is going to involve significant compromises in either handling, $$$, or driveline set-up.
2" lifted 105, lockers, and occasional wincing has taken me everywhere a 4" lifted 80 did
Edit
meant to type winching, but as you can see by the factory side steps, there's definitely some wincing involved too
meant to type winching, but as you can see by the factory side steps, there's definitely some wincing involved too
icorradoi
SILVER Star
Edit
meant to type winching, but as you can see by the factory side steps, there's definitely some wincing involved too
I winced at that pic too!
I have 3" (75MM) Slinky HD springs on order and Slee control arms on their way. Getting rid of my OME 850/863 springs and I'll be running Icon shocks front and rear. According to Slee the arms are made for their 6" lift and give about 8 degrees of measured caster change. With my current lift and one inch spacers in the front and the OME bushings, my caster is currently at 0 and my truck feels darty at freeway speeds. I'm thinking I'll end up with about 5-6 degrees of positive caster with this set up. I'll get an alignment done and report back when it's all together.
The Mud world would appreciate you letting us know how your rig drives and the castor numbers with the new set up.I winced at that pic too!
I have 3" (75MM) Slinky HD springs on order and Slee control arms on their way. Getting rid of my OME 850/863 springs and I'll be running Icon shocks front and rear. According to Slee the arms are made for their 6" lift and give about 8 degrees of measured caster change. With my current lift and one inch spacers in the front and the OME bushings, my caster is currently at 0 and my truck feels darty at freeway speeds. I'm thinking I'll end up with about 5-6 degrees of positive caster with this set up. I'll get an alignment done and report back when it's all together.
I winced at that pic too!
I have 3" (75MM) Slinky HD springs on order and Slee control arms on their way. Getting rid of my OME 850/863 springs and I'll be running Icon shocks front and rear. According to Slee the arms are made for their 6" lift and give about 8 degrees of measured caster change. With my current lift and one inch spacers in the front and the OME bushings, my caster is currently at 0 and my truck feels darty at freeway speeds. I'm thinking I'll end up with about 5-6 degrees of positive caster with this set up. I'll get an alignment done and report back when it's all together.
I would love 5° - 6° of caster on my 80 series and you will love it to.
- Thread starter
- #33
This is actually turning into a great thread keep it comin guys.
I had the OME yellow caster bushing plus the MAF drop bracket & it drove like a dream. I figure I was at around +5* derees. Since then I have stock bushings in there & I want my 5* degrees of caster back.
Last time I checked Slee arm correct 11* degrees
8+3=11
Here is a chart I found that is consistent with what has been written above posts.
I had the OME yellow caster bushing plus the MAF drop bracket & it drove like a dream. I figure I was at around +5* derees. Since then I have stock bushings in there & I want my 5* degrees of caster back.
Last time I checked Slee arm correct 11* degrees
8+3=11Here is a chart I found that is consistent with what has been written above posts.
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Nice typo by Slee in that chart.
Those figures are based on standard caster being 3degrees.
My 1990 FSM is ambiguous on caster, it shows two sets of figures for factory tolerance for caster
60' = 60 minutes = 1°.
Based on that table, a standard cruiser could come from the factory with as little as 2/3 of a degree of caster??
That FSM confuses me, as it shows two very different caster settings based on tyre size, but there's no way to change caster if you do change tyre size.
If be interested to know if the FSM changed in later versions. I'm sure I've seen it shown only as 3° +/- 60' ?
From 1990 FSM
I have been mulling over this in my mind and I don’t believe that if one added Slee arms to already installed castor plates the two mods would add up. My reasoning may be off but if the plates have already adjusted 4*, the arms will simply finishing bringing the 7* or whatever the arm manufacture claims castor increase will be with the arm alone.This is actually turning into a great thread keep it comin guys.
I had the OME yellow caster bushing plus the MAF drop bracket & it drove like a dream. I figure I was at around +5* derees. Since then I have stock bushings in there & I want my 5* degrees of caster back.
Last time I checked Slee arm correct 11* degrees
Here is a chart I found that is consistent with what has been written above posts.
View attachment 1720395
And those Bushings suck so they will fail sooner, One day I am going to make my own Radius arms to solve this
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Yes.
I think the best design goal for any multi-use suspension is balance. The more travel you add or modifications you make, the more difficult balance becomes.
This is easy to watch when people start modifying swaybars instead of just taking them off.
That doesn’t mean there is only one right answer, although most vehicles have a pretty obvious sweet spot.
