Caster Specification for the JL

Roky

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True. The thing definitely pulls tho, usually to the right, which I've read is a symptom of high caster. Hopefully I'll hear back from Teraflex tomorrow.
Check your toe, it might be out, set it to 1/16” toe in and try that.
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dlporter

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I just had my ‘18 JLUR aligned after installing 2.5” Teraflex ST2 lift. They said that the caster is not adjustable? It’s at 7.1 . I’ve seen others in this thread saying 6.0 is ok? How to adjust if it’s not factory adjustable? Caster kit?
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I realize this is an old thread, but figured I’d chime in with my experience. I have the same teraflex ST2 lift and 37s as well. My caster numbers were around the same 7 degree mark also. It drives really well, but i definitely feel it in 4hi above 40 mph. My front driveshaft was replaced with a Woods 1350 driveshaft as well.
 

MattT69

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New 2" Duratrac Eurosport lift plus 1/2 teraflex load leveler spacer with teraflex sport LCAs. Castor is at 7.4 after alignment. It rides smooth and straight as an arrow, no wandering. Not sure why stock JLR is more like 4.8 +/-1 ... Maybe that is why stock felt so jittery at high speeds...
 

wbee

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New 2" Duratrac Eurosport lift plus 1/2 teraflex load leveler spacer with teraflex sport LCAs. Castor is at 7.4 after alignment. It rides smooth and straight as an arrow, no wandering. Not sure why stock JLR is more like 4.8 +/-1 ... Maybe that is why stock felt so jittery at high speeds...
That seems like quite a bit of caster. I wonder if the drive line will vibrate in 4WD at speed. In 2WD it won’t matter because of the FAD. You’ll have to let us know how it goes.
 

MattT69

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I realize this is an old thread, but figured I’d chime in with my experience. I have the same teraflex ST2 lift and 37s as well. My caster numbers were around the same 7 degree mark also. It drives really well, but i definitely feel it in 4hi above 40 mph. My front driveshaft was replaced with a Woods 1350 driveshaft as well.
Same reading with my 2door JLR , My caster is at 7.4 and they said its not adjustable...it drive straight and feels solid on the road. Will a new front driveshaft make a difference 🤔 my lift is the danatrac euro 2 with .5 load spacer so exactly 2.5inch with new teraflex sport LCA..
 

dlporter

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Same reading with my 2door JLR , My caster is at 7.4 and they said its not adjustable...it drive straight and feels solid on the road. Will a new front driveshaft make a difference 🤔 my lift is the danatrac euro 2 with .5 load spacer so exactly 2.5inch with new teraflex sport LCA..
A new driveshaft probably won’t help with driveline vibrations in this case. As I mentioned earlier, I have a Tom woods 1350 driveshaft and it would start vibrating at about 40mph. Caster number greater than 6 degrees mean that the front pinion is slightly pointed down toward the ground, which is not great for the front driveline.

I’ve since replaced all of my control arms with teraflex alpine ir arms. I set the front uppers to stock length and the front lowers to 24 5/16 inches (5/16 inches shorter than the lower sport arms). I haven't had it aligned yet, so I don’t know what my new caster numbers are, but it did help quiet the front driveshaft down a little. It didn’t completely correct the vibrations, but it is better.
 

MattT69

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A new driveshaft probably won’t help with driveline vibrations in this case. As I mentioned earlier, I have a Tom woods 1350 driveshaft and it would start vibrating at about 40mph. Caster number greater than 6 degrees mean that the front pinion is slightly pointed down toward the ground, which is not great for the front driveline.

I’ve since replaced all of my control arms with teraflex alpine ir arms. I set the front uppers to stock length and the front lowers to 24 5/16 inches (5/16 inches shorter than the lower sport arms). I haven't had it aligned yet, so I don’t know what my new caster numbers are, but it did help quiet the front driveshaft down a little. It didn’t completely correct the vibrations, but it is better.
Great Point, maybe need to get the upper control arms longer to match the lower control arms. Thanks for the response!
 

MattT69

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That seems like quite a bit of caster. I wonder if the drive line will vibrate in 4WD at speed. In 2WD it won’t matter because of the FAD. You’ll have to let us know how it goes.
So I tested the JLR Rig in 4-hi up to 50mph and still no change. It drove straight with no vibrations. I even went hands-free on the straight-away with no issues, HMMM??? not sure if I should still order the Upper Control Arms to match the longer LCA from Teraflex...
 

dlporter

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So I tested the JLR Rig in 4-hi up to 50mph and still no change. It drove straight with no vibrations. I even went hands-free on the straight-away with no issues, HMMM??? not sure if I should still order the Upper Control Arms to match the longer LCA from Teraflex...
if it’s driving straight and smooth, I wouldn’t worry about it.
 

jlgolfcart

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if it’s driving straight and smooth, I wouldn’t worry about it.
So I had the Mopar lift put on at the dealership. I have 315/70/17 KO2 with 33psi. I don’t do any wheeling just fire trails. I have the new sterling box and Fox steering stabilizer. My Jeep wonders much more than before. Here’s my alignment sheet. If I need to add longer LCA I would like to go with no maintenance LCA. Please help with suggestions.

DDD85004-6BEF-4023-9380-90EE420A8CDD.jpeg
 

Roky

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So I had the Mopar lift put on at the dealership. I have 315/70/17 KO2 with 33psi. I don’t do any wheeling just fire trails. I have the new sterling box and Fox steering stabilizer. My Jeep wonders much more than before. Here’s my alignment sheet. If I need to add longer LCA I would like to go with no maintenance LCA. Please help with suggestions.

DDD85004-6BEF-4023-9380-90EE420A8CDD.jpeg
Yeah, you’re in a Rubi, they are already low on caster, combined with you probably got more than 2”’of lift, those lcas are useless to you now. Get which ever brand adj. lca you want and get your caster to 6-6.5 degrees, it will show out of spec on alignment sheet but that’s ok, it’s what you want when it comes to caster.
 

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So I had the Mopar lift put on at the dealership. I have 315/70/17 KO2 with 33psi. I don’t do any wheeling just fire trails. I have the new sterling box and Fox steering stabilizer. My Jeep wonders much more than before. Here’s my alignment sheet. If I need to add longer LCA I would like to go with no maintenance LCA. Please help with suggestions.

DDD85004-6BEF-4023-9380-90EE420A8CDD.jpeg
if you're looking for easy use maybe check out synergy arms. They aren't jam nuts and they can be adjusted without having to drop and end of the arm and retorquing every time.
 

CodyB

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This thread has been a big help. I had an RK Ulti Adv. Series 2.5in lift put on my 20 2dr JL Rubicon. I am running 37's. After bringing it back from the shop, steering on the highway was twitchy as heck. After reading this thread and plenty of investigation with a digital angle finder, I determined that I was running about 4.5° of castor. Bottoming out the adjustment in my UCA's got me to 5.9°, and the steering is improved. It seems like I can still use a bit more angle, but I will need to add adjustable LCA's. Thanks to everyone for sharing your experiences.
 

Fuel Fire Desire

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Older thread, but relevant I guess...

I have a Sport S that had a sagged front suspension from a heavy bumper/ winch by just over an inch. After installing the Mopar lift on RK isolators, which gained me 5” over what I had before, I noticed the springs had no outward bow (yay) but had a slight forward bow. The coils are within 1/8”-1/4” from the sway bar links. I had thought it was the spring isolators, but started thinking it was a caster issue. Sure enough, the axle measures 2 degrees forward, which means I’m only at 4 degrees of caster. Still within the 4.80+-1.00, but on the very edge.

It drives no worse than it did before (a bit darty, but it’s been like that since new), but the coil/ sway bar clearance bothers me. It looks like 6 degrees is the caster to aim for with lifted JL’s? I’m currently on 285/70R17’s, but will be going up to 35x12.50’s soon. I’d guess adjustable LCA’s are in my future?
 

Hucke_250

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Older thread, but relevant I guess...

I have a Sport S that had a sagged front suspension from a heavy bumper/ winch by just over an inch. After installing the Mopar lift on RK isolators, which gained me 5” over what I had before, I noticed the springs had no outward bow (yay) but had a slight forward bow. The coils are within 1/8”-1/4” from the sway bar links. I had thought it was the spring isolators, but started thinking it was a caster issue. Sure enough, the axle measures 2 degrees forward, which means I’m only at 4 degrees of caster. Still within the 4.80+-1.00, but on the very edge.

It drives no worse than it did before (a bit darty, but it’s been like that since new), but the coil/ sway bar clearance bothers me. It looks like 6 degrees is the caster to aim for with lifted JL’s? I’m currently on 285/70R17’s, but will be going up to 35x12.50’s soon. I’d guess adjustable LCA’s are in my future?
You’ll definitely benefit from a set of lower control arms. I’d also get a front adjustable track bar to center the front axle left to right.
 
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