MOPAR lift confusion

[ShadowsPapa]

Think about what you are doing with a lift that is spacers that go at the end of the spring. You are not compressing anything, you are not increasing weight. You are putting a spacer in there that is 2". If you have a spring on the table that is 15" tall and it has a brick on it and you measure the bottom of the brick to the top of the table, it's 15". So now you lift the spring up and put a 2" block of wood under it - and measure from the brick to the table top - it would be 17" - right?
How can one raise the spring up 2" and not raise the body that's resting on that spring up 2"?
You are adding 2" to the length of the spring in a way. The spring supports the body - all sprung weight.

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[Len]

Love the tires and rims! What size rims are those they don't look like stock Jeep wheels?
Len

 

[bgenlvtex]

Think about what you are doing with a lift that is spacers that go at the end of the spring. You are not compressing anything, you are not increasing weight. You are putting a spacer in there that is 2". If you have a spring on the table that is 15" tall and it has a brick on it and you measure the bottom of the brick to the top of the table, it's 15". So now you lift the spring up and put a 2" block of wood under it - and measure from the brick to the table top - it would be 17" - right?
How can one raise the spring up 2" and not raise the body that's resting on that spring up 2"?
You are adding 2" to the length of the spring in a way. The spring supports the body - all sprung weight.

Mopar lift is not a spacer lift.

It is springs, control arms,shocks and end links.

That's why it is $1250 not $250

 

[ShadowsPapa]

Mopar lift is not a spacer lift.

It is springs, control arms,shocks and end links.

That's why it is $1250 not $250

Gotcha, thanks.
Does it also drop the control arm pivot points to keep the arms more parallel to the ground than just longer and letting them hang at an increased angle?

 

[bgenlvtex]

Gotcha, thanks.
Does it also drop the control arm pivot points to keep the arms more parallel to the ground than just longer and letting them hang at an increased angle?

The control arms are longer to correct caster

 

[ShadowsPapa]

The control arms are longer to correct caster

And that makes sense - my wondering is that with the new distance the axle is from the chassis - the arms have to swing down in an arc, meaning they are no longer nearly straight out to the axle but angle farther down from the frame to the axle. That means that if the axle moves over a rough spot and moves down, the arm swings down and the arc is increased, pulling that arm back more than if it was nearly a straight line forward. Caster changes would be more drastic. The curb height caster may be correct due to the longer arms, but because they are dropped down farther in front to connect to the axle, they are also further back in the swing or arc.

Please pardon the crude drawing - but as you lower the axle away from the frame, the control arm has to swing down. As it swings down it moves back, pulling the lower side of the axle back, changing caster.
If the control arm attachment point to the frame is lowered, you level the arm again and decrease the backward swing as the arm swings.
Some vehicles actually have a modified arm that has a piece that jogs up to the frame attachment lowering the BACK of the control arm, keeping the arm parallel to the ground.
As you space the axle down, the front of the control arm also has to move down. The rear of the control arm is fixed at the frame bracket. Since the arm swings in a circle, it swings BACK. You compensate by using a longer arm - however, the swing is still changed as the arm will swing back or forward now for every inch of axle movement than it did at the old height.

The bottom image is my crude way of showing how lowering the rear of the arm reduces the caster changes as the truck moves over rough ground.

I guess I'm wondering- are the arms simply longer - or do they compensate for the modified swing of a lift?

 

[bgenlvtex]

And that makes sense - my wondering is that with the new distance the axle is from the chassis - the arms have to swing down in an arc, meaning they are no longer nearly straight out to the axle but angle farther down from the frame to the axle. That means that if the axle moves over a rough spot and moves down, the arm swings down and the arc is increased, pulling that arm back more than if it was nearly a straight line forward. Caster changes would be more drastic. The curb height caster may be correct due to the longer arms, but because they are dropped down farther in front to connect to the axle, they are also further back in the swing or arc.

Please pardon the crude drawing - but as you lower the axle away from the frame, the control arm has to swing down. As it swings down it moves back, pulling the lower side of the axle back, changing caster.
If the control arm attachment point to the frame is lowered, you level the arm again and decrease the backward swing as the arm swings.
Some vehicles actually have a modified arm that has a piece that jogs up to the frame attachment lowering the BACK of the control arm, keeping the arm parallel to the ground.
As you space the axle down, the front of the control arm also has to move down. The rear of the control arm is fixed at the frame bracket. Since the arm swings in a circle, it swings BACK. You compensate by using a longer arm - however, the swing is still changed as the arm will swing back or forward now for every inch of axle movement than it did at the old height.

The bottom image is my crude way of showing how lowering the rear of the arm reduces the caster changes as the truck moves over rough ground.

I guess I'm wondering- are the arms simply longer - or do they compensate for the modified swing of a lift?

The control arms are longer and are not straight.

There is no need in relocating the mount.

 

[ShadowsPapa]

The control arms are longer and are not straight.

There is no need in relocating the mount.

If they are not straight that likely takes care of my question.

 

[HorneyBadger]

then you go 37's lol

Yea, probably rub with 37's but I like the thought!

 

[ShadowsPapa]

Same of you guys seem to be a little confused here. No matter if you put the 2" Mopar lift on a rubicon or sport s the lift will be exactly the same since you are removing your factory suspension which the rubicon sets about .75 -1" higher than the sport s. With that being said if you add a spacer kit (2" higher) to the rubicon suspension you will have a 3" total instead of a 2" lift you are getting from Mopar.. and you still get to keep your nice factory ride without having to switch out from shocks that are exactly the same just about .5" taller for more travel.

Just informing some who are confused from what I have been total and measurements that have been taken from the grown up on both vehicles.

>>confused from what I have been total and measurements that have been taken from the grown up on both<<

Talk about confusing..................... not sure what that means, but I'll guess - I suspect 'total' should be "told" and 'grown up' should read "ground up".

To keep things even, for a control measure, when measuring from the GROUND up - you are then including tires, so you can't count that - it ain't apples to apples...........
so you have to subtract the tire difference to get the difference that is suspension only.
OR choose a different place to measure.
Perhaps measure axle to some frame or body point.
In any case, account for the tire differences.
Otherwise you are including tires and that's going to really confuse things as not everyone will be running stock tires for sure - even on the dealer lots many have already been swapped.

 

[Harold0819]

The difference is that the front springs are the same height in a Sport S or Rubicon. The Rubicon has a different spring rate that has a higher resting height than the Sport. The lift is the same whether it is a Sport or a Rubicon but the gain appears less on a Rubicon since it starts off slightly higher. Yes the high line fenders and larger tires add to this. We are likely only talking about maybe .75" of suspension height difference but still enough to give impression you are getting 2" on a Rubicon and closer to 3" on a sport S or Overland.

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