Different values for left/right caster: How much is too much?

[wandrur]

I took my Jeep in for an alignment check. They adjusted my right wheel toe-in and provided a before and after readout that included the caster readings.

My left side caster is 6.8.
My right side caster is 7.4.

I've done a little reading, and I've seen mention of slight differences to account for crowned roads, but that difference was more commonly in the .25 degree difference rather than as large as my .6 degree difference. The dealer told me my only option to attempt to balance things would be to install adjustable lower control arms (LCAs).

The ask: Please talk to me about differences in caster angle on a Wrangler, preferably from an applied rather than theoretical stance.

Context:
I have a 2021 JLUR with 9200 miles. I've had wandering steering since purchase. My dealer performed the steering gear box replacement even though my year/model wasn't part of the TSB. If the steering to start was a 5/10, this made it a 7/10. My Jeep now also pulls slightly to the left. Was basically told to go pound sand when I took it back in for the wander and the pull.

I added the Mopar LCAs for the 2" lift which are 1/4" longer than the stock JL LCAs. No tangible improvement.

I also added a Falcon Nexus steering stabilizer. This brought highway steering to maybe a 7.5/10, though the wheel does not recenter when the stabilizer is on the firm setting, so anything *not* on highway get a little reminiscent of a non-power steering vehicle.

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[Roky]

I took my Jeep in for an alignment check. They adjusted my right wheel toe-in and provided a before and after readout that included the caster readings.

My left side caster is 6.8.
My right side caster is 7.4.

I've done a little reading, and I've seen mention of slight differences to account for crowned roads, but that difference was more commonly in the .25 degree difference rather than as large as my .6 degree difference. The dealer told me my only option to attempt to balance things would be to install adjustable lower control arms (LCAs).

The ask: Please talk to me about differences in caster angle on a Wrangler, preferably from an applied rather than theoretical stance.

Context:
I have a 2021 JLUR with 9200 miles. I've had wandering steering since purchase. My dealer performed the steering gear box replacement even though my year/model wasn't part of the TSB. If the steering to start was a 5/10, this made it a 7/10. My Jeep now also pulls slightly to the left. Was basically told to go pound sand when I took it back in for the wander and the pull.

I added the Mopar LCAs for the 2" lift which are 1/4" longer than the stock JL LCAs. No tangible improvement.

I also added a Falcon Nexus steering stabilizer. This brought highway steering to maybe a 7.5/10, though the wheel does not recenter when the stabilizer is on the firm setting, so anything *not* on highway get a little reminiscent of a non-power steering vehicle.

That is to much… take some measurements, have someone help you…. Measure the lcas make sure they’re the same length, measure from rear lca bolt to front lca bolt on drivers and passenger side, measure from front bumper or any good spot back to axle lca brackets etc… see if there’s any differences….. you’ll have to be proactive, there’s no silver bullet here….. and as you’re finding out, some but not all dealerships are a little less than useless………

 

[Yellow Cake Kid]

You are correct in thinking that it is common for the passenger side Caster angle to be a tiny bit, e.g. 0.25°, slacker than the driver side.

Your Jeep seems like a good candidate for adjustable length control arms, but bear in mind that many high quality control arms require a complete turn of a 12 thread per inch mechanism which constrains the adjustment to increments of approximately 0.5 degrees.

 

[Terpsmandan]

Might consider adjustable LCA's and then you can get the caster angle exact. I know that this is JL Forum but I have a 2009 JK with 225k. One of the techs at the dealership I work at asked if my track bar was loose because he was following me down I-490 and said it looked like the Jeep was all over the road. Pretty sure most of my CA bushing are shot. It's something to look into once I can afford down time when my new one gets here.

 

[hoag4147]

That is to much… take some measurements, have someone help you…. Measure the lcas make sure they’re the same length, measure from rear lca bolt to front lca bolt on drivers and passenger side, measure from front bumper or any good spot back to axle lca brackets etc… see if there’s any differences….. you’ll have to be proactive, there’s no silver bullet here….. and as you’re finding out, some but not all dealerships are a little less than useless………

@wandrur Wonder how got that much of difference just installing the longer Mopar LCAs ?‍. Did all front (upper and lower) controls arms get loosened when installing longer LCAs, and then torqued once back on the ground?

 

[wandrur]

@wandrur Wonder how got that much of difference just installing the longer Mopar LCAs ?‍. Did all front (upper and lower) controls arms get loosened when installing longer LCAs, and then torqued once back on the ground?

No, per many instructions and experiences read here, I swapped the LCAs with Jeep on the ground and only dealt with the LCA bolts on and off.

 

[Birdcatcher]

Old thread, but just my 2 cents...

I have a 2022 JLUR 392 (non XR). Caster was 3.7 left, 4.0 right from factory. Drove horrible (it was unsafe). Dealer did not care, said it's a Jeep thing.

Switched over to adjustable LCA's.

Stock LCA's are 24". I started with exact 9.0 mm over stock adjustment (that's just over 3/8 inches).

Brought caster to 5.5 and 6.0. So, Longer MOPAR would not have cut it in my case).

Got them adjusted again, little less than half an inch over stock. Caster is now at 6.2 and 6.5.

It is not perfect but safe to drive on a highway.

As per the reputed off-road workshop where I got this done, the axle welds/ suspension mount welds between Front Left vs Right are around .25" off. So there will always be a 0.3 to 0.5 degree difference in Caster between Front Left vs Right.

It's a Jeep thing! Awesome build quality!

 

[Fast-n-Furious]

Just wanted to share my before and after the Mopar LCAs swap if can be any help to anyone who searches for this topic. My stock 392 XR was great to drive even before the swap, the extra 1/4” length does improve the ride and increase 1 degree caster angle. Now it tracks a bit better and has better return-to-center.

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