What should my caster angle be?
- Thread starter Breto31
- Start date
I guess my next question would be: When adjusting the upper CA’s, do I need to remove BOTH arms at the same time (at the axle) to shorten them - or - do one at a time? I’m thinking removing both sounds like the proper way.
I reached out to Core 4x4 and they were very helpful. They sent me the attached chart outlining their recommended CA lengths. Looks like they recommend the same length (15”) for all upper CA from stock to 4.5” lift.
First, I plan to measure my current CA’s to see where they stack up against Core 4x4’s recommendations, and then adjust as needed.
I reached out to Core 4x4 and they were very helpful. They sent me the attached chart outlining their recommended CA lengths. Looks like they recommend the same length (15”) for all upper CA from stock to 4.5” lift.
First, I plan to measure my current CA’s to see where they stack up against Core 4x4’s recommendations, and then adjust as needed.
To adjust the castor anything more than a tiny amount, you will need to remove both. Otherwise, if you pull one, adjust it, and try to reinstall it, it will be nearly impossible to reinstall the bolt.
You can do it with the rig on the ground, but be sure to chock all four wheels so the axle doesn’t roll on you when you unbolt the control arms. Take care to adjust each arm the same amount.
You can do it with the rig on the ground, but be sure to chock all four wheels so the axle doesn’t roll on you when you unbolt the control arms. Take care to adjust each arm the same amount.
I measured my CA’s this morning based off of the measurements that Core 4X4 provided for a 4” lift. The uppers look to be right at the proper 15”. The lowers look to be a smidge short at 16 1/8” compared to the 16 3/8” that Core says.
Would adjusting the lowers out a bit by 1/4” (to reach 16 3/8”) increase my caster at all, or should I go more out to 3/8” (to get to 16 1/2”)?
Would adjusting the lowers out a bit by 1/4” (to reach 16 3/8”) increase my caster at all, or should I go more out to 3/8” (to get to 16 1/2”)?
We don't do it that way ever. There is nothing that says that both upper control arm mounts are in exactly the same spot.
If you set arms dimensionally the same, that can easily put them in a bind fighting each other.
Remove the bolt from one end of one upper. Adjust the other upper to set pinion/caster and leave the bolt at one end loose.
When you are happy with the adjustment, jack up the front side of the axle to relieve the pressure on the loose bolt so you can turn it easily. When that is done, adjust the other upper arm over until you can get the bolt in, that now sets the load on both uppers the same and they aren't fighting each other.
This assumes one is smart enough to do all this on level ground without the vehicle leaning over to one side.
I’m assuming this process would apply to the lowers too?
I measured my CA’s based on the chart that Core 4x4 sent me. For the 4” lift, my lowers measured a little short….. Would adjusting the lowers out a bit by 1/4” (to reach 16 3/8”) increase my caster at all, or should I go more out to 3/8” (to get to 16 1/2”)?
LONGJP2
TJ Expert
Is this your first Jeep?
Solid front axle vehicle is going to react to road a little differently than IS. Add steering gear vs. rack and pinion, and it's lifted from stock; it all adds up to a different experience.
Its not my first Jeep, but it’s my first TJ. I drove a YJ for a few years when I was younger (2.5” lift, 32’s), and my dad had a CJ7 (6” lift and 35’s).
I understand that the shorter wheel base will feel differently than, say, my F150. I don’t believe that this is normal, however. The reason being, it didn’t do this when I bought it. It drove fine. I really only started noticing it after I put my new CA’s on while chasing a wheel shimmy, which makes me think that my caster may be off slightly after the change. I didn’t my best to keep the length the same as my original arms, but I don’t believe I did.
Much clearer explanation, Blaine. I was mainly responding to Bret’s question of whether he could do one arm at a time, which with his single adjustables you can’t (as you describe). My comment about adjusting the arms the same length was just wrong - thinking about it I’ve never done it that way either, but rather do it just the way you describe. Been a while since I’ve had to deal with single adjustable arms.
Thanks for clarifying - you are the master.
When you guys add caster (by extending the lower arm length), how do you recommend getting the axle to actually line back up to the arm hole? Obviously the longer arm won’t line back up to the existing axle position, and the axle will need to be rotated a bit to achieve the additional caster.
Lots of videos show ratchet straps being used to pull the axle, but I didn’t know what everyone recommended to accomplish that.
Lots of videos show ratchet straps being used to pull the axle, but I didn’t know what everyone recommended to accomplish that.
You can rotate it with the factory jack either above or below the nose through which the pinion shaft exits.
I adjusted my lower CA’s out today from 16 1/4” to 16 3/8” per the Core 4X4 specs for a 4” lift. Feels like it rides/drives better on the highway, but can’t say much difference for the backroads.
Also, my return to center still sucks. Here’s a video. It’s very slow, and doesn’t return all the way back to center - same way it was before.
Also, my return to center still sucks. Here’s a video. It’s very slow, and doesn’t return all the way back to center - same way it was before.
What is your caster angle? Check that your toe-in is correct and what air pressure is in your tires?
Not sure what the caster or toe-in is right now. I just did the adjustments a few mins ago, and none of the alignment shops are open. I’m planning to get by there this week and see if I can get a printout or at least a pic of the screen.
Tire pressure is at about 28-29 psi.
The CA adjustment ended up being about 3 full turns to get to the recommended height.
For what it’s worth, I think the lack of return to center with the steering is a big issue with my “darting”…. Its almost like when the road dips/dives, the steering wheel/suspension pulls and moves with the contour of the road, and since the return to center is garbage, I am constantly having to correct it because the steering is not fighting against it.
Am I off-base with that assessment?
Am I off-base with that assessment?
Too wide of wheel stance will also cause wander, look at what your back space is. Here is an exaggerated example of all roads due to tire wear, too wide and the vehicle will dart from side to side...
What am I using this angle finder for? Seeing what the caster angle is?
Where do you measure your caster angle from anyway?