Is 4 degree caster angle a problem?


Mr. Bills

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Not unless your jeep tries to wander as you go down the road. How large are your tires? Larger tires seem to require less caster.
 

Jerry Bransford

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I just had an alignment and my caster angle was measured at 4 degrees, is this a problem?
4 degrees is a little light. How tall is the lift, what size tires do you have, and are your control arm lengths adjustable?

Does your Jeep steer stable down the highway and does the steering wheel return back to center after completing a turn?
 
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Glenn Hodges

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The lift is 2.5" (actually a 3.25 without the 3/4 inch spring spacer).
Tires are 32.5 (255/75R17) JK tires with lug adapters. Control arms are stock.
I've not driven many highway miles, the jeep does seem to be sensitive to undulation in the road.
I will need to take notice of the steering returning to center. I have some play I need to eliminate.
I am strongly considering longer control arms in the near future.
Don't know why but I prefer rigid arms over adjustable??? Fewer variables, I guess.
 

Jerry Bransford

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Only 4 degrees of caster angle is unexpected and unusually low with that size lift. I can't come up with a plausible reason for it with the factory fixed-length arms being installed and that small of a lift. For your 32.5" tires, I'd want closer to 6 degrees. Was that 4 degree caster angle given to you verbally or is it on a printout?

Caster angle is not a critical angle, it doesn't need to be some exact number, you just need enough caster angle to give stable steering on the highway and good steering return-to-center after completing a turn.
 
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Jerry Bransford

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I'm in total agreement and would like to get back to 6. The 4 degrees is from a computer alignment printout (LF3.9, RF4.0)
What is the best way to fix this, the alignment tech mentioned eccentric bolts?
There is a cam bolt kit made for the front axle that allows the caster angle to be adjusted slightly. IIRC its range of adjustment is only something like +/- 1.5 degrees. but it might do the trick. Otherwise a pair of adjustable length arms would be the way to go.

TJs used to come with those cam bolts in '97 to mid-99 model years. :)

Looks like this...

Cam bolt.JPG
 
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BendLarry

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A cam bolt is a common solution to minor caster adjustments. I find it interesting though that it’s being offered as a solution. I was beat up pretty good a few months ago for suggesting the very same cam bolts as a solution for my caster issue. I guess it matters more who makes the suggestion than whether or not the information is viable.


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Erik V

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I have what I believe to be 6 deg caster angle and my return to center sucks.
06 TJ X with 2” lift and 33X10.50 tires.

Mine has the cam bolts front and rear.
 

1515art

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2006 Rubicon 3 1/2” lift (more like 4) I’m dealing with this issue again too, dropped a chunk of my paycheck at 4 wheel parts last year on new front control arm hardware after it got loose on me and did some damage to the cam bolts and mount, now I just caught them loose again after noticing excessive wandering on the highway. I’d just put 33’s on it so both things at the same time kind of hid the issue a little with me wondering if the wandering was due to the new tires. Saw some slight movement in the front axle backing up looking out the drivers side window, checked the control arm bolts and saw clearly where the passengers side had a 3/4” shadow where the cam bolt had moved from it’s previous spot. I’m guessing the castor went as far to the positive as the play allowed and was also acting dynamic while driving? I was thinking of going for 5 deg positive castor with my set-up, should I shoot for 6? I used a floor jack to gently push the lower control arm mount back to what looked like the correct place and tightened the cam bolt to 108’#’s, I have a new set of cam bolts on order and will replace them and do the adjustments when they come in to the store. Also bought some square tube and clamps to check the toe angle, anything else to look for. Thanks for starting this thread hope I’m on topic enough to jump on. Thanks again
 

Jerry Bransford

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I'd go for 6 degrees but if that causes any new vibrations which would indicate that caused excessive pinion angle, just drop back a tad on the caster angle until the vibration goes away. I'd think you'd be able to get 6 degrees without problem with your amount of suspension lift.
 
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1515art

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I'd go for 6 degrees but if that causes any new vibrations which would indicate that caused excessive pinion angle, just drop back a tad on the caster angle until the vibration goes away. I'd think you'd be able to get 6 degrees without problem with your amount of suspension lift.

Jerry, thank you. I’ll be working on it tomorrow, something slipped driving home on the freeway tonight and the rest of the drive home was pretty unpleasant, felt like a large boat. Turn the wheel and wait’n see how far then back, combined with road crown float and just a tiny bit of the start of the o’l DW, (probably going 65-70 a tiny bit to fast for the moment). Picked up one of those gauges I shouldn’t use at Home Depot earlier for measuring castor, so guess I’ll just use it for the basic install set-up and then have a shop dial it in, unless it drives just like I want then, we’ll probably still good a idea anyway to have it put on something accurate?