Caster Specification for the JL

[Fuel Fire Desire]

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.

Already there. Adjustable track bar front and rear were put on by me before I dropped it off at the dealer for the lift to go on. With a 5” change in height, there would have been a healthy shift. I was hoping I could get away with the Mopar LCA’s, which I guess I could being I’m within caster spec....but the spring clearance really bothers me. The added stability on the highway will be a bonus.

Just out of curiosity, is there a known length or formula to determine additional LCA length required to achieve a desired caster? I have stock UCA’s, and need to gain 2 degrees over the mopar lift LCA’s. Or is it just a trial and error thing?

Sponsored

 

[Roky]

Already there. Adjustable track bar front and rear were put on by me before I dropped it off at the dealer for the lift to go on. With a 5” change in height, there would have been a healthy shift. I was hoping I could get away with the Mopar LCA’s, which I guess I could being I’m within caster spec....but the spring clearance really bothers me. The added stability on the highway will be a bonus.

Just out of curiosity, is there a known length or formula to determine additional LCA length required to achieve a desired caster? I have stock UCA’s, and need to gain 2 degrees over the mopar lift LCA’s. Or is it just a trial and error thing?

I would start at 24-1/2”. If that 5” is all lift and not lift plus tire size increase together, then you’ll likely have to go longer.

 

[Fuel Fire Desire]

I would start at 24-1/2”. If that 5” is all lift and not lift plus tire size increase together, then you’ll likely have to go longer.

The 5” is all Mopar lift. My sport is about 1.5” below factory height from sagging, which is 1.5” below rubicon height, which is what the Mopar lift is supposed to add 2” to. So I wound up gaining 5” immediately after install. I fully expect the front to sag again after the suspension settles from the weight of the bumper/ winch, but will be throwing on a spacer lift up front to level it. So it’s still going to be about 5” taller up front from what I started with, or 4” above a factory fresh sport.

The Mopar lift LCA’s just don’t cut it. They’re on the very shallow edge of being in spec. Which I honestly expected.....


‘Having not done adjustable LCA’s before, how much of a bear is it to do one side at a time? Is there any give to the axle when trying to install a longer LCA one side at a time? Or am I going to have to drop the axle again? I’m trying to decide if I can do this with my hydro jack and two jack stands in my driveway.

 

[Roky]

The 5” is all Mopar lift. My sport is about 1.5” below factory height from sagging, which is 1.5” below rubicon height, which is what the Mopar lift is supposed to add 2” to. So I wound up gaining 5” immediately after install. I fully expect the front to sag again after the suspension settles from the weight of the bumper/ winch, but will be throwing on a spacer lift up front to level it. So it’s still going to be about 5” taller up front from what I started with, or 4” above a factory fresh sport.

The Mopar lift LCA’s just don’t cut it. They’re on the very shallow edge of being in spec. Which I honestly expected.....


‘Having not done adjustable LCA’s before, how much of a bear is it to do one side at a time? Is there any give to the axle when trying to install a longer LCA one side at a time? Or am I going to have to drop the axle again? I’m trying to decide if I can do this with my hydro jack and two jack stands in my driveway.

You can do it on the ground, if you need to you can use a floor jack to manipulate the axle , but it’s not that bad.

 

[Greg H]

The 5” is all Mopar lift. My sport is about 1.5” below factory height from sagging, which is 1.5” below rubicon height, which is what the Mopar lift is supposed to add 2” to. So I wound up gaining 5” immediately after install. I fully expect the front to sag again after the suspension settles from the weight of the bumper/ winch, but will be throwing on a spacer lift up front to level it. So it’s still going to be about 5” taller up front from what I started with, or 4” above a factory fresh sport.

The Mopar lift LCA’s just don’t cut it. They’re on the very shallow edge of being in spec. Which I honestly expected.....


‘Having not done adjustable LCA’s before, how much of a bear is it to do one side at a time? Is there any give to the axle when trying to install a longer LCA one side at a time? Or am I going to have to drop the axle again? I’m trying to decide if I can do this with my hydro jack and two jack stands in my driveway.

I just drove mine up on ramps in my garage. Did one side at a time. After I got the new one on one side I left the bolts loose while doing the other side. I placed an angle finder on the differential after pulling it onto the ramps to get a reading that I could compare to before I started so I'd know how much caster I had gained while adjusting. Had to go back and forth between the 2 sides until I got the caster to 6.3. Then torqued everything down. My caster with my Dynatrac Endurosport 2" lift was at 3.3 with the stock 24" LCA. My new ones are set at 24 5/16" to get me to 6.3. Hardest part was breaking the bolts loose. I sprayed them with WD40 about an hour before I started to help loosen them up.

 

[Fuel Fire Desire]

I just drove mine up on ramps in my garage. Did one side at a time. After I got the new one on one side I left the bolts loose while doing the other side. I placed an angle finder on the differential after pulling it onto the ramps to get a reading that I could compare to before I started so I'd know how much caster I had gained while adjusting. Had to go back and forth between the 2 sides until I got the caster to 6.3. Then torqued everything down. My caster with my Dynatrac Endurosport 2" lift was at 3.3 with the stock 24" LCA. My new ones are set at 24 5/16" to get me to 6.3. Hardest part was breaking the bolts loose. I sprayed them with WD40 about an hour before I started to help loosen them up.

I’m lucky in that regard. The Mopar lift is less than a month old, and there’s no rust yet. I already picked up a 30” breaker bar in anticipation of pulling the body mount bolts for a better set of sliders, so breaking the suspension loose again shouldn’t be too hard. When I did my track bars, the bolts popped loose fairly easily with my craptastic Ryobi battery impact.

 

[wbee]

when I adjusted my lower control arms. I parked the Jeep on my garage floor and engaged the parking brake. I put a bottle jack under back side of the front diff, there a flat spot there to support the diff and keep it from twisting. I remove the bolts on the control arms and lower the bottle jack very slowly to my desired caster and lengthen the control arms and bolt them back in place. I can do it in about 30 minutes. Hopefully this help someone.

 

[DanW]

My caster with the Mopar lift and no Rancho brackets turned out to be 5 degrees on both sides. So with the brackets it had to be easy over that.

 

[Fuel Fire Desire]

How much pinion angle can the factory front driveshaft tolerate? I have a Mopar lift on a sport with a 3/4” spacer going in (to compensate for the pig of a bumper/ winch I have). The pinion is at +2 degrees, leaving my castor at 4. I’d like to get my castor to 5-6, but don’t want to trash the CV flange on the T-case side of the driveshaft (or worse).

 

[Tech Tim]

With 5" of lift, I recommend a set of geometry correction brackets too. They will help get you control arms back to a decent angle

 

[Fuel Fire Desire]

With 5" of lift, I recommend a set of geometry correction brackets too. They will help get you control arms back to a decent angle

Its a total gain of 5” over what I lost from sagging (my bumper/ winch combo is a pig at nearly 180 lbs). There was so much loss before the lift the factory LCA’s were actually angled slightly upward. If it were a virgin sport it would be more like 3.5”. The lift is also only a few weeks old, so I’m expecting sag, but am throwing on a 3/4” leveling kit to get ahead of anticipated loss. So when it’s all said and done it will wind up being 3.5” total. The Mopar supplied LCA’s look to be at a much more normal angle now. I’m more concerned about having a 0 degree pinion angle with the factory CV driveshaft if I adjust castor to 6 degrees.

The Jeep doesn’t drive bad right now. It’s as unstable on the highway as it was stock (not terrible, but requires constant steering inputs), the thing that drew my attention to castor was the front springs being bowed just slightly forward. After measuring I found I was at around 4 degrees. These tires are 3/4 worn 285/70R17’s with an actual measured diameter of 32” unloaded. 35x12.50’s are on the way, and the increased trailing tread from the larger diameter should help with directional stability as well even without adjustable LCA’s. I’d still like to add LCA’s, but am just afraid of over doing it with pinion angle and munching the CV. I’d really like to avoid having to do a front driveshaft on a sport with just a Mopar lift.

 

[word302]

With 5" of lift, I recommend a set of geometry correction brackets too. They will help get you control arms back to a decent angle

Meh, 5” on a sport is like 3.5” a rubicon. No way I’d add correction brackets.

 

[word302]

Its a total gain of 5” over what I lost from sagging (my bumper/ winch combo is a pig at nearly 180 lbs). There was so much loss before the lift the factory LCA’s were actually angled slightly upward. If it were a virgin sport it would be more like 3.5”. The lift is also only a few weeks old, so I’m expecting sag, but am throwing on a 3/4” leveling kit to get ahead of anticipated loss. So when it’s all said and done it will wind up being 3.5” total. The Mopar supplied LCA’s look to be at a much more normal angle now. I’m more concerned about having a 0 degree pinion angle with the factory CV driveshaft if I adjust castor to 6 degrees.

The Jeep doesn’t drive bad right now. It’s as unstable on the highway as it was stock (not terrible, but requires constant steering inputs), the thing that drew my attention to castor was the front springs being bowed just slightly forward. After measuring I found I was at around 4 degrees. These tires are 3/4 worn 285/70R17’s with an actual measured diameter of 32” unloaded. 35x12.50’s are on the way, and the increased trailing tread from the larger diameter should help with directional stability as well even without adjustable LCA’s. I’d still like to add LCA’s, but am just afraid of over doing it with pinion angle and munching the CV. I’d really like to avoid having to do a front driveshaft on a sport with just a Mopar lift.

With the Mopar lift your front driveshaft will be fine. You have to get some pretty extreme articulation to tear it up. If you were running Metalcloak or Rock Krawler you’d have a problem.

 

[Fuel Fire Desire]

With the Mopar lift your front driveshaft will be fine. You have to get some pretty extreme articulation to tear it up. If you were running Metalcloak or Rock Krawler you’d have a problem.

Nah. I don’t flex much at all. It’s used to get me in and out of my northern Michigan properties, which is all forestry trails. It doesn’t see rocks. I don’t even disconnect on those, because there just isn’t a need.

 

[word302]

Nah. I don’t flex much at all. It’s used to get me in and out of my northern Michigan properties, which is all forestry trails. It doesn’t see rocks. I don’t even disconnect on those, because there just isn’t a need.

Yeah you’ll be fine dialing that caster in to 6-6.5°. Remember the driveshaft doesn’t even spin in 2wd.

Sponsored