Suspension Tech Have a question about modifying your suspension? Ask it here.

Modified Camber/Caster adjustment cams. Need help.

  #1  
Old 05-02-2015, 07:14 PM
dharvey4651's Avatar
New Member
Thread Starter
Join Date: Jun 2011
Location: Kansas
Posts: 52
dharvey4651 is on a distinguished road
Default Modified Camber/Caster adjustment cams. Need help.

So I have the RC 2.5" suspension lift and a nice set of 31" BFG'S that are quickly becoming junk BFG'S thanks to a very annoying positive camber issue.

I've aligned my truck probably 5-6 times since I installed the lift and the camber keeps going positive and out of spec.

I found these eccentric cam plates on Rough Country's website that says they're compatible with 99-up GM's.

http://www.roughcountry.com/gm-cam-plates-1002.html

The problem is that all the models listed under the compatibility table are full sized trucks like Silverado's and Tahoe's.

Has anyone here ever installed these cams on their upper control arm bolts and if so, did they actually make a difference?
 

Last edited by dharvey4651; 05-02-2015 at 07:19 PM.
  #2  
Old 05-02-2015, 07:54 PM
Captain Hook's Avatar
Moderator
Join Date: Mar 2009
Location: Belleville, Michigan
Posts: 8,445
Captain Hook is a jewel in the roughCaptain Hook is a jewel in the roughCaptain Hook is a jewel in the rough
Default

Originally Posted by dharvey4651 View Post
So I have the RC 2.5" suspension lift and a nice set of 31" BFG'S that are quickly becoming junk BFG'S thanks to a very annoying positive camber issue.

That's one of the trade offs for a suspension lift. Tires, along with steering & suspension parts will wear out prematurely. Front chassis ride height must be within factory spec, for camber to remain within factory spec.
The cams will not fit on T series, they are for full size only.
 
  #3  
Old 05-02-2015, 08:38 PM
dharvey4651's Avatar
New Member
Thread Starter
Join Date: Jun 2011
Location: Kansas
Posts: 52
dharvey4651 is on a distinguished road
Default

Though the cams may not fit, I respectfully disagree about the ride height / camber statement. My left front camber is dead nuts center. Along with caster and toe. And that's lifted.

Its only the right front that has been giving me issues.

I've rounded off several eccentric cams trying to get my camber and caster into spec and was able to bring my right front camber down to 0.8 which is actually within spec. Its on the high side of spec but still in spec.

The caster is another story though. It is at about -1.2 with my camber at 0.8.

I just want to fix it and I know it's gotta be fixable. I just don't know how. Short of elongating the lower control arm mounting holes and pulling the lower control arm further out away from the frame...
 
  #4  
Old 05-02-2015, 10:28 PM
Captain Hook's Avatar
Moderator
Join Date: Mar 2009
Location: Belleville, Michigan
Posts: 8,445
Captain Hook is a jewel in the roughCaptain Hook is a jewel in the roughCaptain Hook is a jewel in the rough
Default

Caster spec is +2 to +4 degrees. Cross caster spec is 1 degree, which is way too much using 31's. At -1.2 degrees, if cross caster is within spec, it will wander like a big dog!


Camber spec is -1 to +1 degrees, cross camber spec is 1 degree, which is also way to much for 31's. You need to be at zero if you expect them to last.


31's have a huge footprint, with some serious traction and rolling resistance. This is why camber & caster need to be set to the desired spec. Factory specs are designed for 235-70-15, a much narrower tire, and far more forgiving.


As front chassis ride height increases, so does camber. Eventually you'll get to a point when it is geometrically impossible to decrease camber without serious modifications. Just for grins & giggles, measure your front chassis ride height and post it. If you need the measuring points and specs, let me know.


With caster at -1.2 degrees, and camber at +.8 degrees, you need to move the rearward end of the upper control arm inward. This will increase caster, and decrease camber. Being lifted though, I doubt you can move it far enough.
 

Last edited by Captain Hook; 05-02-2015 at 10:39 PM.
  #5  
Old 05-02-2015, 11:00 PM
dharvey4651's Avatar
New Member
Thread Starter
Join Date: Jun 2011
Location: Kansas
Posts: 52
dharvey4651 is on a distinguished road
Default

Originally Posted by Captain Hook View Post
Caster spec is +2 to +4 degrees. Cross caster spec is 1 degree, which is way too much using 31's. At -1.2 degrees, if cross caster is within spec, it will wander like a big dog!
It does. Believe me. When you let go of the steering wheel, It pulls to the right so hard that you'd think you were exiting the highway. Actually... When my exit is coming up I truthfully just let go of the steering wheel lol.

Originally Posted by Captain Hook View Post
As front chassis ride height increases, so does camber. Eventually you'll get to a point when it is geometrically impossible to decrease camber without serious modifications. Just for grins & giggles, measure your front chassis ride height and post it. If you need the measuring points and specs, let me know.
From center of hub to bottom of fender, my ride height is between 20 & 3/4" - 21", left and right. Rough Country says my rude height should be 21" so I'm right on the money.

With my ride height where it is, my driver side alignment is dead nuts center. Passenger side has serious positive camber.

Originally Posted by Captain Hook View Post
With caster at -1.2 degrees, and camber at +.8 degrees, you need to move the rearward end of the upper control arm inward. This will increase caster, and decrease camber. Being lifted though, I doubt you can move it far enough.
I cannot adjust either eccentric in the passenger upper control arm any further inwards without rounding them off. Believe me I've tried and rounded off more than one eccentric already.
 
  #6  
Old 05-02-2015, 11:26 PM
Captain Hook's Avatar
Moderator
Join Date: Mar 2009
Location: Belleville, Michigan
Posts: 8,445
Captain Hook is a jewel in the roughCaptain Hook is a jewel in the roughCaptain Hook is a jewel in the rough
Default

It pulls because cross caster is out of spec. But you knew that already


You can't move the eccentric any farther, because the front chassis ride height is too far out of spec.

"From center of hub to bottom of fender, my ride height is between 20 & 3/4" - 21", left and right. Rough Country says my rude height should be 21" so I'm right on the money."


This is NOT an accurate way to measure front chassis ride height. Body height changes with chassis ride height, but you're not concerned with body height. It is what it is, when front chassis ride height is within spec. What you're concerned with, is front chassis ride height so you can get the alignment where it needs to be, to save your BFG's.


Name:  Frontchassisrideheight_zps1c940df5.jpg
Views: 1518
Size:  118.5 KB


Vehicle must be on a level surface, front to rear, and side to side. All four wheels on the ground. Vehicle loaded like it normally is when you drive it. Measure a plumb line from the pivot bolt center down to the ground, and a plumb line from the lower most inboard point of the knuckle down to the ground. Subtract knuckle to ground measurement from pivot bolt to ground measurement. Do this on both sides, and post the measurement.


EDIT: The vertical red arrow is front chassis ride height.
 

Last edited by Captain Hook; 05-02-2015 at 11:33 PM.
  #7  
Old 05-02-2015, 11:40 PM
dharvey4651's Avatar
New Member
Thread Starter
Join Date: Jun 2011
Location: Kansas
Posts: 52
dharvey4651 is on a distinguished road
Default

Originally Posted by Captain Hook View Post
It pulls because cross caster is out of spec. But you knew that already


You can't move the eccentric any farther, because the front chassis ride height is too far out of spec.

"From center of hub to bottom of fender, my ride height is between 20 & 3/4" - 21", left and right. Rough Country says my rude height should be 21" so I'm right on the money."


This is NOT an accurate way to measure front chassis ride height. Body height changes with chassis ride height, but you're not concerned with body height. It is what it is, when front chassis ride height is within spec. What you're concerned with, is front chassis ride height so you can get the alignment where it needs to be, to save your BFG's.





Vehicle must be on a level surface, front to rear, and side to side. All four wheels on the ground. Vehicle loaded like it normally is when you drive it. Measure a plumb line from the pivot bolt center down to the ground, and a plumb line from the lower most inboard point of the knuckle down to the ground. Subtract knuckle to ground measurement from pivot bolt to ground measurement. Do this on both sides, and post the measurement.


EDIT: The vertical red arrow is front chassis ride height.
Ok see this measurement is new to me. I'm familiar and accomplished as a technician and with aligning vehicles but this is my first experience dealing with a lifted vehicles as I work for an auto manufacturer that doesn't presently sell trucks.

I will definitely get that measurement for you. I don't know of any level surfaces to park on besides at work and they're shut down for the weekend so it'll be later unfortunately.
 
Attached Thumbnails Modified Camber/Caster adjustment cams. Need help.-frontchassisrideheight_zps1c940df5.jpg  
  #8  
Old 05-02-2015, 11:50 PM
dharvey4651's Avatar
New Member
Thread Starter
Join Date: Jun 2011
Location: Kansas
Posts: 52
dharvey4651 is on a distinguished road
Default

Basically what you're saying though is that my chassis ride height is not even left to right and that's why I'm able to align the left side but not the right? If that were the case then how would one correct that?
 
  #9  
Old 05-03-2015, 10:54 AM
Captain Hook's Avatar
Moderator
Join Date: Mar 2009
Location: Belleville, Michigan
Posts: 8,445
Captain Hook is a jewel in the roughCaptain Hook is a jewel in the roughCaptain Hook is a jewel in the rough
Default

Not necessarily level left and right, but the possibility exists, causing your difficulty. In the image, notice the angle of the CV halfshaft, almost level. Front chassis ride height is what makes and keeps it where it must be in order to have full adjustment of camber.

You could get a ballpark measurement sitting on a relatively flat surface, but for an accurate measurement and adjusting, the vehicle must be level.

The torsion bar adjusters are at the rearward end of the torsion bars. Clockwise increases ride height, counterclockwise decreases ride height. Ideally it should be with in one 16th of an inch side to side. If you really want it accurate, have someone with the approximate same weight as the driver, sit in the drivers seat while you check and adjust ride height.


Specs:


1996 & newer:
4WD (except ZR2) = 4.6” to 5.0” (4.8” is preferred)
4WD ZR2 = 4.6” to 5.2” (4.9” is preferred)

 

Last edited by Captain Hook; 05-03-2015 at 11:43 AM.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
95blazerlt
2nd Gen S-series (1995-2005) Tech
1
03-08-2014 05:40 PM
basicconcepts
2nd Gen S-series (1995-2005) Tech
0
02-28-2011 01:22 PM
freakgt
Steering, Suspension & Drivetrain
1
08-25-2010 06:38 PM
jsmz
Lifting Tech
6
12-25-2009 12:23 PM
ChevyBlazer1989
Steering, Suspension & Drivetrain
2
07-14-2009 06:00 PM


Thread Tools
Search this Thread
Quick Reply: Modified Camber/Caster adjustment cams. Need help.


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.