Cam Bolts

[ShadowsPapa]

Stock TJ caster is 7 degrees.

So was ZJ and I believe WJ was likely 7
Will look up camber as well.
The solid axle Grand Cherokees had 7 degrees caster, OK range was 6.5 to 7.5.

They steered fine, tracked nicely, wheel returned to center about like the JT does. They were great highway vehicles and not so bad in town, either.

JT castor should be 4.5. But people extend that to 5 to control that wander. It shouldnt have to be touched on a stock JT.

And that's less than a few IFS cars which come in at 4.75 with a range extending higher than that. A tall, square, flat-sided truck - sort of interesting that the caster spec is lower than some cars.

Think of it - WJ, ZH, TJ, 7 with a top of 7.5 and the JT is 2.5 to 3 degrees less than that.

5 is where a number of other trucks have been as I recall.

I can see reduced caster for a longer wheelbase vehicle than the short Jeeps or even some SUVs but that's a fair drop.

I'll see if I can find my other JT specs (camber, etc.) and go from there.

Now here's the fun part (for me, anyway). I collect TSMs for cars I'm interested in. Even more fun is the later supplements and addendums.
Take one of those cars to an alignment shop and they have the spec, right there from the factory, exactly as published in the original documentation. The problem with that is that in no small number of cases, the engineers later CHANGED those specs - and you see the updated specs in the supplements and addendums to the TSM - but no one ever bought or used those so the shop will align to the original, incorrect specs.
I've even printed pages from the updated service specs and handed them to shops only to get a car back with the alignment set to the original release specs - wrong.
What should that tell people? When a vehicle is released - they release specs that are suitable with all of the information available at that time. After a vehicle hits the streets, they get more information, there's more internal testing and changes and updates, and they release new, updated specs.
The JT is a newer vehicle - I'd not be shocked to see new specs come out for some things. I'm not saying they will, or that there's even a great chance - just saying - I've seen it before, so no surprise. It may be the face of a Wrangler, but the ass is a truck.
We may hit 2024 model year with the exact same parts and specs. Maybe not. Changes have happened before - and even before a model year was completed.

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[j.o.y.ride]

Why add more to a stock vehicle?

The stock caster is absurd. IMO it's to make it feel more responsive on test drives around the lot and surface streets. Steep caster like we have will be easier to turn. But it's also much more prone to wander and death wobble.

 

[ShadowsPapa]

The stock caster is absurd. IMO it's to make it feel more responsive on test drives around the lot and surface streets. Steep caster like we have will be easier to turn. But it's also much more prone to wander and death wobble.

"steep caster" ?? What do you mean by "Steep"?

These don't have near the caster some vehicles have.
What we have doesn't make it easier to turn - 1 or 2 degrees would make it easier to turn.
It's light compared to other Jeep vehicles.
If you don't have enough positive caster the vehicle will wander and feel unstable. If you have too much positive caster, the vehicle will be harder to turn.
Negative caster makes it really easy to turn and was generally used with manual steering.
As power steering came into favor, caster settings started being more on the positive side.

If the JT is 4.5 - that's 4.5 positive caster and that's hardly steep, nor is it low.
It's low compared to other Jeep vehicles of past years.
Positive caster resists turns because you are literally lifting the front of the vehicle on turns. That's part of the tendency of high-caster settings to self-center after a turn. The weight of the vehicle causes them to go back to straight.
"caster like we have" isn't what makes it easier to turn - the soft power steering system is what does that.
The PS on these sort of reminds me of earlier MOPAR systems. Pretty easy to turn and 4.5 degrees positive doesn't make one easy to turn. 1 or 2 would. 0 or negative would really be easy to turn.

 

[j.o.y.ride]

--whole bunch of stuff--

Steep as in, you know, steep. When they're more upright than things that are not steep. Like when things get... steep. Makes the truck feel more responsive and easier to steer. I never said light, you said light. And then went off on some unrelated tangent. As is tradition.

 

[ShadowsPapa]

Steep as in, you know, steep. When they're more upright than things that are not steep. Like when things get... steep. Makes the truck feel more responsive and easier to steer. I never said light, you said light. And then went off on some unrelated tangent. As is tradition.

Unrelated? Trying to figure out how you can call these "steep" as it's a term you don't see with caster - apparently you haven't done many alignments and don't know what low caster settings really are.
Unrelated? LOL - yeah, explaining caster in a thread about caster is unrelated.

BTW - Specs for Wrangler (JK) 4.2 less than JT JL is 4.8 - not really different than JT. Actually, they are all pretty comparable. Many trucks run less.

 

[John D. Upton]

I’m curious why Jeep/Stellantis would engineer the suspension with castor that is too low from the factory.

it’s not a cost thing. An upper or lower arm that is a tiny bit longer or shorter wouldn’t cost any different.

Any suspension gurus know why?
@ShadowsPapa
Tagging you Pops as you’ve been around the block, a few times.

So was ZJ and I believe WJ was likely 7
Will look up camber as well.
The solid axle Grand Cherokees had 7 degrees caster, OK range was 6.5 to 7.5.

They steered fine, tracked nicely, wheel returned to center about like the JT does. They were great highway vehicles and not so bad in town, either.


And that's less than a few IFS cars which come in at 4.75 with a range extending higher than that. A tall, square, flat-sided truck - sort of interesting that the caster spec is lower than some cars.

Think of it - WJ, ZH, TJ, 7 with a top of 7.5 and the JT is 2.5 to 3 degrees less than that.

5 is where a number of other trucks have been as I recall.

I can see reduced caster for a longer wheelbase vehicle than the short Jeeps or even some SUVs but that's a fair drop.

I'll see if I can find my other JT specs (camber, etc.) and go from there.

Now here's the fun part (for me, anyway). I collect TSMs for cars I'm interested in. Even more fun is the later supplements and addendums.
Take one of those cars to an alignment shop and they have the spec, right there from the factory, exactly as published in the original documentation. The problem with that is that in no small number of cases, the engineers later CHANGED those specs - and you see the updated specs in the supplements and addendums to the TSM - but no one ever bought or used those so the shop will align to the original, incorrect specs.
I've even printed pages from the updated service specs and handed them to shops only to get a car back with the alignment set to the original release specs - wrong.
What should that tell people? When a vehicle is released - they release specs that are suitable with all of the information available at that time. After a vehicle hits the streets, they get more information, there's more internal testing and changes and updates, and they release new, updated specs.
The JT is a newer vehicle - I'd not be shocked to see new specs come out for some things. I'm not saying they will, or that there's even a great chance - just saying - I've seen it before, so no surprise. It may be the face of a Wrangler, but the ass is a truck.
We may hit 2024 model year with the exact same parts and specs. Maybe not. Changes have happened before - and even before a model year was completed.

My 2021 Rubicon from the factory is at4° and doesn't drive as it should. Ordered new lower arms to get the caster to 6° in order to stop road wander and having to have so much steering input to go down the road.

 

[HorneyBadger]

Didnt find the JT specs but here are the JL specs. So pretty much 4 to 6 degrees

 

[HorneyBadger]

Ahh, JT specs!

 

[ShadowsPapa]

Slight negative camber - interesting.........

 

[Sargerub]

My 2021 Rubicon from the factory is at4° and doesn't drive as it should. Ordered new lower arms to get the caster to 6° in order to stop road wander and having to have so much steering input to go down the road.

Did the new arms correct the problem?

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