Rear Spring Relocation Without Adding Height?

[freedom_in_4low]

Same boat from what I'm seeing.. only Rancho seems have anything close for both ends. Fronts are easy.
If I'd be ok with different brands front & rear are these out of the question or too much trouble to mess with? One of my questions was whether to avoid anything over 11" travel?

SJ BM B8563 16.05/27.33/11.28

Same travel but 0.83 shorter compressed and 0.92 shorter extended.

There's no reason to avoid a shock just because of its overall travel. Usually there are limits on the downtravel that end up indirectly limiting travel.

The driveshafts are one example. The arc of the control arms moves backward faster than the front driveshaft so at a lot of droop your driveshaft slip joint may bottom out. I bought a new front shaft for this. The double cardan in the rear may bind when the rear axle is fully dropped due to the extreme angle. Jjvw runs a center limit strap in the rear for this one.

My lower shock brackets hit the top of the lower control arms fairly early, so I've trimmed them to clear enough to actually reach the end of the rs55255.

There are probably other limits as well, such as when the rod ends in the steering reach the end of their travel, the brake lines turn into guitar strings, the front jounce bumper cup plucks the spring in compression after a full droop (my reason for using rockjock bump stops) ... This why we cycle so much.

 

[someguysjeep]

whether to avoid anything over 11" travel?

whatever you can make fit in the space in the ball park of 1/2 way in the travel range.

 

[someguysjeep]

Jjvw runs a center limit strap in the rear for this one

not for much longer.

 

[jjvw]

not for much longer.

Give me a bit more time!

 

[freedom_in_4low]

Give me a bit more time!

What are you doing to get rid of it? Atlas?

When I checked this on my TJ which did not have a tuck, the DC bound around 27" of shock length. The rs55332 will be well into that territory.

 

[notnsuv]

There's no reason to avoid a shock just because of its overall travel. Usually there are limits on the downtravel that end up indirectly limiting travel.

The driveshafts are one example. The arc of the control arms moves backward faster than the front driveshaft so at a lot of droop your driveshaft slip joint may bottom out. I bought a new front shaft for this. The double cardan in the rear may bind when the rear axle is fully dropped due to the extreme angle. Jjvw runs a center limit strap in the rear for this one.

My lower shock brackets hit the top of the lower control arms fairly early, so I've trimmed them to clear enough to actually reach the end of the rs55255.

There are probably other limits as well, such as when the rod ends in the steering reach the end of their travel, the brake lines turn into guitar strings, the front jounce bumper cup plucks the spring in compression after a full droop (my reason for using rockjock bump stops) ... This why we cycle so much.

Are these contradictory statements?
First one is holy crap! More to think about and what to do about it (bump stops?). Or a bunch more cycling and 'work'?

The second is, yeah, that's what I wanna hear (but is it gonna get me in trouble?).

whatever you can make fit in the space in the ball park of 1/2 way in the travel range.

 

[jjvw]

What are you doing to get rid of it? Atlas?

....

The plan is to push the rear back about 6".

 

[notnsuv]

Are these contradictory statements?
First one is holy crap! More to think about and what to do about it (bump stops?). Or a bunch more cycling and 'work'?

The second is, yeah, that's what I wanna hear (but is it gonna get me in trouble?).

And what of the KYB Monotube front, reportedly one of the stiffer shocks, paired with the twin tube Black Max rear, reportedly one of the softest shocks? The weight up front is consistent, the rear will vary with the load I'm hauling but never 'lite' with 35" spare and steel bumper, hardtop, but no backseat.

 

[freedom_in_4low]

The plan is to push the rear back about 6".

Oh, that's right. That ought to do it.

 

[someguysjeep]

(but is it gonna get me in trouble?).

you control the trouble with the proper bumps and you can tether the axle if you droop beyond what the driveshaft likes.

 

[freedom_in_4low]

Are these contradictory statements?
First one is holy crap! More to think about and what to do about it (bump stops?). Or a bunch more cycling and 'work'?

The second is, yeah, that's what I wanna hear (but is it gonna get me in trouble?).

Somewhat contradictory yes... But only because you're at so high a lift. Most people 4" and below don't run into these situations, so the other answer is usually valid.

Since we're talking about extension, bump stops don't help. It would be a limit strap, a shock selection with an extended length appropriate to act as a limit, or to do something else get rid of the interference (like a shorter front shaft and trimming the shock brackets).

 

[notnsuv]

Somewhat contradictory yes... But only because you're at so high a lift. Most people 4" and below don't run into these situations, so the other answer is usually valid.

Since we're talking about extension, bump stops don't help. It would be a limit strap, a shock selection with an extended length appropriate to act as a limit, or to do something else get rid of the interference (like a shorter front shaft and trimming the shock brackets).

Or solve the issues with shorter springs, like 4". The BL is in there. I already lowered 2" - and no more nose bleeds.

 

[jjvw]

You can find out if the droop will hurt the driveshaft by disconnecting the driveshaft from the axle, hanging the axle from the shocks and bolting the shaft back on twice at 90deg from the first try.

This is mostly a problem with the Rubicon.

 

[notnsuv]

You can find out if the droop will hurt the driveshaft by disconnecting the driveshaft from the axle, hanging the axle from the shocks and bolting the shaft back on twice at 90deg from the first try.

Bolt it back up as it was then turn the u-joint 90* for the 2nd try?

This is mostly a problem with the Rubicon.

LJ Rubicon included?

Or skip the longer shocks and settle for less than optimal. It is just a trail rig, not a crawler.

 

[freedom_in_4low]

Bolt it back up as it was then turn the u-joint 90* for the 2nd try?

LJ Rubicon included?

Or skip the longer shocks and settle for less than optimal. It is just a trail rig, not a crawler.

I must have forgot we were dealing with an LJ. The rear driveshaft is highly unlikely to give an issue there. It's driveshaft is 50% longer, so it'll handle 50% more droop, which is massive.

 

[jjvw]

Bolt it back up as it was then turn the u-joint 90* for the 2nd try?

...

Bolt it up. If it goes on easily, remove it again. Turn the shaft and pinion 90 deg and try again. If it bolts on easily both times, there isn't a problem.

....

LJ Rubicon included?

Or skip the longer shocks and settle for less than optimal. It is just a trail rig, not a crawler.

This is a problem with the TJ Rubicon's short rear driveshaft. On mine with a 4" spring lift, a high center skid and 6" of droop, the driveshaft starts to bind at about 5.25" of droop. I have a limit strap above the diff to protect the driveshaft without sacrificing articulation.

If I am successful with this rear wheelbase stretch, I will be able to eliminate the strap.

 

[notnsuv]

Bolt it up. If it goes on easily, remove it again. Turn the shaft and pinion 90 deg and try again. If it bolts on easily both times, there isn't a problem.
This is a problem with the TJ Rubicon's short rear driveshaft. On mine with a 4" spring lift, a high center skid and 6" of droop, the driveshaft starts to bind at about 5.25" of droop. I have a limit strap above the diff to protect the driveshaft without sacrificing articulation.

If I am successful with this rear wheelbase stretch, I will be able to eliminate the st

So, can I put the longer shocks back in the equation? I'm only looking at those for the rear and will stay with a more conventional set up front.

Like this combo:

Front: Rancho RS55255 15.69/10.73/26.42 5.31 up 5.42 down

Rear: Rancho RS55332 16.88/11.28/28.25 5.12" up 6.22" down
Rear: Rancho RS55256 15.06/9.63/24.69 5.94" up 3.69" down

And cycle after installation would likely be prudent.

 

[freedom_in_4low]

So, can I put the longer shocks back in the equation? I'm only looking at those for the rear and will stay with a more conventional set up front.

Like this combo:

Front: Rancho RS55255 15.69/10.73/26.42 5.31 up 5.42 down

Rear: Rancho RS55332 16.88/11.28/28.25 5.12" up 6.22" down
Rear: Rancho RS55256 15.06/9.63/24.69 5.94" up 3.69" down

And cycle after installation would likely be prudent.

If you really end up with the RS55332 I would recommend splitting the rear bump stop extensions between top and bottom. Most often people put them on the top only, but I think you're gonna end up with 4+ inches and they're not going to line up very well if it's all on top.

 

[jjvw]

So, can I put the longer shocks back in the equation? I'm only looking at those for the rear and will stay with a more conventional set up front.

Like this combo:

Front: Rancho RS55255 15.69/10.73/26.42 5.31 up 5.42 down

Rear: Rancho RS55332 16.88/11.28/28.25 5.12" up 6.22" down
Rear: Rancho RS55256 15.06/9.63/24.69 5.94" up 3.69" down

And cycle after installation would likely be prudent.

I would lean towards the 55256.

 

[notnsuv]

If you really end up with the RS55332 I would recommend splitting the rear bump stop extensions between top and bottom. Most often people put them on the top only, but I think you're gonna end up with 4+ inches and they're not going to line up very well if it's all on top.

On @jjvw recommendation, I'd already planned that regardless of the shock I select.