Caster Specification for the JL

[Predatorjl]

Okay so here's a new one for you guys. I've read this entire thread and It only accounts for factory axles.

How about aftermarket axles. I just finished installing Ultimate 60s front and rear on my JLS.
Full RK 3.5 X Factor all adjustable arms. Steer Smarts Tierod and Drag link as well as Trackbar. 40 inch Nitto Trail Grapplers and Adams Driveshafts front and rear.

Spicer says run 4.8. Before the axle swap I was at 5.5.
Seeing most are finding success around 6. Any input.

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[Tech Tim]

Okay so here's a new one for you guys. I've read this entire thread and It only accounts for factory axles.

How about aftermarket axles. I just finished installing Ultimate 60s front and rear on my JLS.
Full RK 3.5 X Factor all adjustable arms. Steer Smarts Tierod and Drag link as well as Trackbar. 40 inch Nitto Trail Grapplers and Adams Driveshafts front and rear.

Spicer says run 4.8. Before the axle swap I was at 5.5.
Seeing most are finding success around 6. Any input.

It really depends on a few things including wheel/tire choice and offset. In a perfect world, you might get by with 4.8, but we find that 6-7° for typical 40" wheel/tire combos and definitely towards the higher end if you are running hydro assist.

 

[Predatorjl]

It really depends on a few things including wheel/tire choice and offset. In a perfect world, you might get by with 4.8, but we find that 6-7° for typical 40" wheel/tire combos and definitely towards the higher end if you are running hydro assist.

Not running Hydro yet but in the future.

My dial indicator off the case spreader hole shows 80* . Off the bottom f the C its between 6-7 and off the yoke to the DS is 6-7 as well. My understanding is if the case shows 90* I should be roughly at 6*

 

[B&Wpro]

Hi.
I need some help with castor angle with jeep rubicon . I have installed with long arm upgrade from ironrockoffroad , but i dont have any lift . I have ko2 37 inch tires which runs small and wheel with 4.5 back space . I set 6.3 with driver and 6.0 with passenger of castor angle . Driving 70ml at highway , i got little bit vibration of handle, so what castor angle should i set up ??

Thanks

 

[Roky]

Hi.
I need some help with castor angle with jeep rubicon . I have installed with long arm upgrade from ironrockoffroad , but i dont have any lift . I have ko2 37 inch tires which runs small and wheel with 4.5 back space . I set 6.3 with driver and 6.0 with passenger of castor angle . Driving 70ml at highway , i got little bit vibration of handle, so what castor angle should i set up ??

Thanks

That’s a little high for long arms. Your arm angles are a lot flatter now so you don’t need as much caster. When I switched to long arms I went from 6.2-6.4 to 5.8-5.9 and it feels better than it did before.

Also it’s better to run a little higher caster on passenger to help with crown in road, unless you have right hand drive, lol.

 

[B&Wpro]

That’s a little high for long arms. Your arm angles are a lot flatter now so you don’t need as much caster. When I switched to long arms I went from 6.2-6.4 to 5.8-5.9 and it feels better than it did before.

Also it’s better to run a little higher caster on passenger to help with crown in road, unless you have right hand drive, lol.

Thanks so much .
I will try to change it tomorrow.

 

[Monster1926]

Not sure if anyone on here can help out, I picked up adjustable LCAs and I am wondering if I should do the UCAs at the same time? The goal is 6-6.5 degrees of caster. Since the Jeep is AWD I’m wondering if I should get the uppers too?

 

[word302]

Not sure if anyone on here can help out, I picked up adjustable LCAs and I am wondering if I should do the UCAs at the same time? The goal is 6-6.5 degrees of caster. Since the Jeep is AWD I’m wondering if I should get the uppers too?

The fact that it’s AWD doesn’t matter. If you have both you can center the wheel in the wheel well. If you only have one or the other you can only adjust caster.

 

[Fuel Fire Desire]

Not sure if anyone on here can help out, I picked up adjustable LCAs and I am wondering if I should do the UCAs at the same time? The goal is 6-6.5 degrees of caster. Since the Jeep is AWD I’m wondering if I should get the uppers too?

I asked Metalcloak about this on the phone. I was surprised to hear them tell me it was unnecessary given that I’m on a Mopar lift, and unless I wanted greater articulation their joints provided by also getting longer shocks (and a new front driveshaft), the LCAs on their own was completely adequate if all I wanted to do was reset pinion angle.

 

[Reinen]

Not sure if anyone on here can help out, I picked up adjustable LCAs and I am wondering if I should do the UCAs at the same time? The goal is 6-6.5 degrees of caster. Since the Jeep is AWD I’m wondering if I should get the uppers too?

No JL is AWD. It's Full-Time 4WD. They're different.
Full-Time 4WD is 2WD (100% rear) unless the rear tires slip, then 4WD kicks in (50% front/50% rear) and it returns to 2WD once traction is regained.
AWD balances power anywhere between 0-100% front/rear.

This has no bearing on your caster.

 

[Roky]

I asked Metalcloak about this on the phone. I was surprised to hear them tell me it was unnecessary given that I’m on a Mopar lift, and unless I wanted greater articulation their joints provided by also getting longer shocks (and a new front driveshaft), the LCAs on their own was completely adequate if all I wanted to do was reset pinion angle.

MC is correct with their response …… the Mopar lift shocks only extend 26.5 ish inches so the axle won’t droop enough to put the UCAs in a bind. Actually they will barely move on the frame side. Only when you get up to 28-30+ inch extended length shocks you’ll need to get adjustable uppers and driveshaft….. you can still rock the oem uppers, but they’ll definitely bind and wear quickly…….

 

[Monster1926]

No JL is AWD. It's Full-Time 4WD. They're different.
Full-Time 4WD is 2WD (100% rear) unless the rear tires slip, then 4WD kicks in (50% front/50% rear) and it returns to 2WD once traction is regained.
AWD balances power anywhere between 0-100% front/rear.

This has no bearing on your caster.

It slightly matters when my front drive shaft is spinning 100% of the time. Just trying to avoid driveline vibrations.

 

[Fuel Fire Desire]

MC is correct with their response …… the Mopar lift shocks only extend 26.5 ish inches so the axle won’t droop enough to put the UCAs in a bind. Actually they will barely move on the frame side. Only when you get up to 28-30+ inch extended length shocks you’ll need to get adjustable uppers and driveshaft….. you can still rock the oem uppers, but they’ll definitely bind and wear quickly…….

Yep. And 90% of people don’t even bother to disconnect. There’s nowhere near the articulation to worry about joint bind or Rzeppa clearance issues on a Mopar lift if left connected. I had some worries about it after seeing how close to the Rzeppa flange was to the driveshaft, but after running the Jeep up a ramp while connected to the point the rear tire was lifting, there was minimal movement and still plenty of clearance. In all honesty, clevite joints are just fine unless you plan on disconnecting.

My Rzeppa flange has a couple kisses on it, but that was only a result of me removing the shocks and dropping the axle to get the springs out. Even with me standing on the drivers side to overcome clevite bind on the Mopar lift LCAs, there was just the slightest contact and deformation. Well beyond the droop allowed by factory or Mopar lift fox shocks.

And by the way, with 4” of actual lift, and 6° of caster (0° pinion) I have zero driveline vibrations up to 50 mph during a test drive.

 

[word302]

It slightly matters when my front drive shaft is spinning 100% of the time. Just trying to avoid driveline vibrations.

Well it’s pinion angle that would cause vibration, and yes it is directly affected when you adjust caster. I haven’t heard of anyone having vibration issues running 6.5° caster.

 

[dginz]

Need some help here. 2018 JLU Sahara. Just had a teraflex 2.5 lift installed (their basic spring lift w/ sway bar end links etc) + Falcon ST2.1 shocks + teraflex geometry correction brackets (stock lca’s), falcon nexus 2.2 steering stabilizer. I have a steersmarts yeti adj front track bar and a rough country rear track bar ready to go on Saturday. Just had my alignment done (attached) and it drives like shit. Throwing me all over the road (slight exaggeration but something feels way off on steering).

I’m running 33in tires right now on method 17x9 -12 offset - plenty of backspacing.

Any ideas? hoping the adj track bars help but I don’t think that’s what’s going on here.

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