Setting caster/pinion? Adjustable control arms - JeepForum.com
 
LinkBack Thread Tools
post #1 of 10 Old 03-27-2020, 04:00 PM Thread Starter
Mr. Puddles
Senior Member
1996 ZJ 
 
Join Date: Mar 2018
Location: Little Elm
Posts: 722
Garage
Setting caster/pinion? Adjustable control arms

Ive got adjustable upper and lower front arms I need to look at installing soon before the weather gets hot. Ive swapped arms before but Ive never had to do it with adjustable arms. If Im reading the suspension correctly Id use the upper arms to set pinion angle and the lowers for caster correct? Or is it a mix of the two?


Follow the build!

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


2002 Dakota aka Winnie aka Mad Max
1996 Grand Cherokee aka Puddles aka Pikey Life
Quote:
Originally Posted by kg6mov View Post
The 4.0 is dumb old tractor motor, itís too stupid to know itís supposed to die.
Mr. Puddles is offline  
Sponsored Links
Advertisement
 
post #2 of 10 Old 03-27-2020, 04:25 PM
CatSplat
Registered User
 
CatSplat's Avatar
1994 ZJ 
 
Join Date: Jul 2009
Location: Calgary
Posts: 1,889
Garage
In general terms, the lowers are first used to set axle location and then the uppers set pinion angle and caster. There's a bit of interplay between both as lengthening the uppers will move the axle forward a bit too, but that's the general idea.


On our solid axles, changing the pinion angle also changes the caster - they are intrinsically linked. You generally need to shoot for a balance between the two.

1994 5.9L ZJ | IRO 5.5" CPLA | NP242 | 33" Cooper Discoverer STT Pro
The Jeep of Theseus
CatSplat is offline  
post #3 of 10 Old 03-27-2020, 04:57 PM
222Doc
Registered User
 
222Doc's Avatar
2012 JK Wrangler 
 
Join Date: Sep 2011
Location: Lake Havasu City
Posts: 9,299
Garage
I would try to set it for caster. If that ends up with vibes, then dial the pinion up a little at a time until its happy. If that ends up with very low or zero caster it wont drive well on the street. The higher the lift the more issues you will have as well the higher the gears are will set of vibes sooner as well.

Like Cal said caster and pinion angle are locked in by where the Cs are welded at the factory. Whats is your caster now? measure that. You can get a free phone app that can do angles rather well or buy a magnetic one. a lifted solid axle will loose caster angle. The more the lift the more its off. but will make that pinion rise up with stock arms. Some adjustable arms its real easy to adjust if they are double ended or have a combination sleeve at one end. Like some Synergy types and i believe Tera flex came up with similar design. Others with say a jamb nut on one side only you will be taking one end off to adjust it and that takes more time.

Home of the Parker Desert Splash

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
222Doc is offline  
 
post #4 of 10 Old 03-27-2020, 05:03 PM Thread Starter
Mr. Puddles
Senior Member
1996 ZJ 
 
Join Date: Mar 2018
Location: Little Elm
Posts: 722
Garage
Not sure what caster is right this moment. My biggest issue is in the pinion angle due tot he cv front shaft. If it were a u joint setup I wouldnt be as concerned.

Follow the build!

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


2002 Dakota aka Winnie aka Mad Max
1996 Grand Cherokee aka Puddles aka Pikey Life
Quote:
Originally Posted by kg6mov View Post
The 4.0 is dumb old tractor motor, itís too stupid to know itís supposed to die.
Mr. Puddles is offline  
post #5 of 10 Old 03-27-2020, 05:16 PM
222Doc
Registered User
 
222Doc's Avatar
2012 JK Wrangler 
 
Join Date: Sep 2011
Location: Lake Havasu City
Posts: 9,299
Garage
Cv meaning a Rzeppa joint ? Or a DC type with three u joints? The Rzeppa joint type are far more forgiving as long as the angle is not out of its range. meaning at fool droop it doesnt get into a bind or near it. when they do the boot tends to fail fast on a CV.

Unless this is say AWD the fronts in a no load so the CD shaft do not have to be perfect in most cases< depend on angle again and gears. people with higher gear ratios tend to run into issues with a DC type shaft. since the drive line speed goes up the ability in a no load become much more of an issue.

You should measure what you have now, so you know where you are going latter. Does it vib now? or do you have issues with caster? caster if to low will make it not want to return to center well. Can lead to loose feeling, wander. if none of the latter then set the new arms at what you have.

Home of the Parker Desert Splash

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
222Doc is offline  
post #6 of 10 Old 03-27-2020, 07:01 PM Thread Starter
Mr. Puddles
Senior Member
1996 ZJ 
 
Join Date: Mar 2018
Location: Little Elm
Posts: 722
Garage
Quote:
Originally Posted by 222Doc View Post
Cv meaning a Rzeppa joint ? Or a DC type with three u joints? The Rzeppa joint type are far more forgiving as long as the angle is not out of its range. meaning at fool droop it doesnt get into a bind or near it. when they do the boot tends to fail fast on a CV.



Unless this is say AWD the fronts in a no load so the CD shaft do not have to be perfect in most cases< depend on angle again and gears. people with higher gear ratios tend to run into issues with a DC type shaft. since the drive line speed goes up the ability in a no load become much more of an issue.



You should measure what you have now, so you know where you are going latter. Does it vib now? or do you have issues with caster? caster if to low will make it not want to return to center well. Can lead to loose feeling, wander. if none of the latter then set the new arms at what you have.
I have a DC Rzeppa. I am not awd anymore about a year ago I swapped in a 242 case. A lot of noise (which I will address later when I start on brakes and hubs) but not much in the way of vibrations. I know my caster angle is little over a half degree off the wrong way (more driver side than passenger) but I dont know the exact numbers. I plan to take it in and get a reading done so I have a known starting point.

The biggest issues I have now is a healthy pull to the right which I suspect is a result of the caster and an odd front end wobble. Comes in about 40 and is gone by 45 but I suffer from dw induced by what I believe is bump steer above 55. Makes for a not fun hour drive to/from work. I know I have a suspension geometry issue that I suspect will help but I think there is a tire issue as well.

Sent from my LM-V405 using Tapatalk

Follow the build!

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


2002 Dakota aka Winnie aka Mad Max
1996 Grand Cherokee aka Puddles aka Pikey Life
Quote:
Originally Posted by kg6mov View Post
The 4.0 is dumb old tractor motor, itís too stupid to know itís supposed to die.
Mr. Puddles is offline  
post #7 of 10 Old 03-27-2020, 07:08 PM
PolkaPower
Registered User
 
PolkaPower's Avatar
1998 ZJ 
 
Join Date: Aug 2011
Location: The Abyss
Posts: 22,815
Get a magnetic angle finder.

Sent from my BND-L24 using Tapatalk
PolkaPower is offline  
post #8 of 10 Old 03-28-2020, 07:16 AM
jcjunkie
Registered User
 
jcjunkie's Avatar
1998 ZJ 
 
Join Date: Dec 2019
Location: Hickory
Posts: 47
Save yourself countless hours and get control arms with sleeves so you can adjust without removing. If you are like me, I had to remove everyone of them and readjust. Took about two days and when your axle flops forward. You'll need ratchet straps to pull axle to the rear and then you'll need two Jack's to stick under the drag link mount and driver side coil spring perch to tilt it backwards.

Major PITA. My time would've been spent better paying a shop. But oh well I learned how to do it better.

Use your phone or buy a magnetic angle finder. To check driveshaft angles and axle angle. It's not to hard just time consuming.

98 5.9
jcjunkie is offline  
post #9 of 10 Old 03-28-2020, 08:08 AM
Timo_90xj
Web Wheeler
 
Timo_90xj's Avatar
1998 ZJ 
 
Join Date: Mar 2006
Location: Helsinki, Finland - on the European side of the Atlantic
Posts: 10,403
Quote:
Originally Posted by Mr. Puddles View Post
Not sure what caster is right this moment. My biggest issue is in the pinion angle due tot he cv front shaft. If it were a u joint setup I wouldnt be as concerned.
In fact, with the Rzeppa + double cardan joint front DS it is MUCH more forgiving for incorrect angles because both of those joint types are constant velocity joints - meaning it does not matter at what angle they are they operate smoothly.
With a single u-joint + double cardan joint, pinion angle usually needs to be very close to optimal or you end up with driveline vibes. That is because you only have a constant velocity joint at the TC, so the operating angle of the single u-joint @ pinion needs to be very close to zero for it not to cause vibes.

The ONLY problem with the Rzeppa- joint is that it has the slip built into the joint, and the fact that the joint itself is not built strong enough. Generally speaking, Rzeppa- joint is the best joint there is. U-joint is a simple design -> fairly cheap & easy to manufacture a strong joint, but that's about the only good thing about them

As for the adjustments, use the LCAs to set wheelbase and UCAs for pinion/ caster angle. However if you look at the link lengths and their mounting locations on the axle, you do realize adjusting either will change WB & caster/ pinion angle. I agree 100% with the post above that dual- adjustable arms are MUCH better because they are easy to adjust without removing the control arm - and more precise adjustment.


1998 Grand Cherokee 5.9 LX daily driver, 1.75" BB, 32" KM2s, HPD30 Eaton e-locker/D44a stock LSD, 4.56 gears, custom- fabbed tube bumpers and tube fenders,...


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.



1990 XJ Limited (4-door), 4.0 I6, AW4, NP242, ***rolled and totalled @ 165k miles***

***Under construction***
1990 XJ (4-door), 4.0 I6, AW4, NP242, PBR 42" tires, Unimog 404 portal axles, 110" WB, full cage + uniframe completely rebuilt, front 3-link + panhard / double triangulated 4-link rear,... ***SOLD***
Timo_90xj is offline  
post #10 of 10 Old 03-31-2020, 03:49 PM Thread Starter
Mr. Puddles
Senior Member
1996 ZJ 
 
Join Date: Mar 2018
Location: Little Elm
Posts: 722
Garage
When I finally have the cash to swap into a long arm kit i plan to do double adjustables. For now Im just trying to get back to where I can safely drive at highway speeds.

Follow the build!

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


2002 Dakota aka Winnie aka Mad Max
1996 Grand Cherokee aka Puddles aka Pikey Life
Quote:
Originally Posted by kg6mov View Post
The 4.0 is dumb old tractor motor, itís too stupid to know itís supposed to die.
Mr. Puddles is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.



Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome