Rear Spring Relocation Without Adding Height?
- Thread starter notnsuv
- Start date
No. I'm currently at 4" on springs and 1.25 body.
My lift progression went from 3/4” spacers to two inch ome springs (they are not 2.5" unless you install spacers), to the OME plus the 3/4" spacers. I thought I was going to stay there and continue on with 33s. But, I was tired of the ride and the compromises that 3" of spring lift force you to make. So...I went full monte on a 35" build. I'm still in process. If you read my "rebuild" thread in my sig, you'll get more of the story.
Did you cycle your suspension to reach that shock length? Are you using all of the shock travel? In other words, are your bump stops being used at the shock limit and how much bump stop do you have?
I've been over a lot of build threads, your 'rebuild' included.
I'll definitely go through it again.
Here's some random notes for where mine ends up.
First of all - I wish we measured lift by the shock instead of the spring, because it's much easier and clearer to measure than a spring that may not be perfectly square or straight, may or may not include aftermarket spacers or isolators, etc. I know it only works for the front since the rear isn't 1:1, but the rear spring is even more difficult to get a good measurement from, so I don't even bother. I just measure the front and then make sure the frame is close to level.
My front shock length at ride height is 20.5" (or 21.125 between the mounts, because the official measurement doesn't include the washer and bushing).
I assume the bushing gets about 1/4" of compression with the Jeeps weight on it, so I subtract that from the compressed length when I calculate uptravel, and this puts me at 4.95/6.03 up/down with the RS55255, 6.23/3.8 with the SJ B8525, 4.19/6.375 with the B8549, and 5.265/4.185 with the KYB 565096. The KYB is the only one I would consider to be a viable replacement for the Rancho.
In the rear, I'm at 19.875" at ride height, putting me at 4.95/4.125 with the RS55256, 5.15/4.125 with the SJ B8528 and 4.6/3.865 with the KYB 565097, so the SJ is the only one I would consider a viable replacement for the Rancho.
EDIT: I even went through the Fox IFP offerings linked on another post I read today, and they have something that would work for the front, but I'd have to compromise on up or down travel on the rear.
Therein lies my dilemma, because if I want to ditch the Ranchos and keep stock mounts, I either have to run different brands front/rear, or give up more than I want to on either up or down travel. My rule of thumb is to get as close as I can to 50/50 while having at least 5 up and 4 down.
First of all - I wish we measured lift by the shock instead of the spring, because it's much easier and clearer to measure than a spring that may not be perfectly square or straight, may or may not include aftermarket spacers or isolators, etc. I know it only works for the front since the rear isn't 1:1, but the rear spring is even more difficult to get a good measurement from, so I don't even bother. I just measure the front and then make sure the frame is close to level.
My front shock length at ride height is 20.5" (or 21.125 between the mounts, because the official measurement doesn't include the washer and bushing).
I assume the bushing gets about 1/4" of compression with the Jeeps weight on it, so I subtract that from the compressed length when I calculate uptravel, and this puts me at 4.95/6.03 up/down with the RS55255, 6.23/3.8 with the SJ B8525, 4.19/6.375 with the B8549, and 5.265/4.185 with the KYB 565096. The KYB is the only one I would consider to be a viable replacement for the Rancho.
In the rear, I'm at 19.875" at ride height, putting me at 4.95/4.125 with the RS55256, 5.15/4.125 with the SJ B8528 and 4.6/3.865 with the KYB 565097, so the SJ is the only one I would consider a viable replacement for the Rancho.
EDIT: I even went through the Fox IFP offerings linked on another post I read today, and they have something that would work for the front, but I'd have to compromise on up or down travel on the rear.
Therein lies my dilemma, because if I want to ditch the Ranchos and keep stock mounts, I either have to run different brands front/rear, or give up more than I want to on either up or down travel. My rule of thumb is to get as close as I can to 50/50 while having at least 5 up and 4 down.
Last edited:
I picked this shock based on how much I estimated my shock mount location distance to increase with the amount of lift I had planned. I was pretty much dead on the money. I took into account the 0.5” or so of shock bushing.
I am using full travel of the shock, as it is the limit to my up travel. When the shock reached its compressed length, I needed 2” of bump stop.
Well, it's a head-scratcher then. Mike is using the same with 4" lift. I'll be measuring again, but the tape doesn't lie.
Edit: Isn't that 2" of bumpstop telling us you're not using 2" of the shock travel?
@Mike_H whats your shock travel looking like?
No. The shock fully compresses and is protected by the additional 2” extension.
I have right about 5.25" of shaft showing at ride height, and I have about 2" of bumpstop
Whelp, I'm gonna do mine all over just for POM. My cycled/full stuff measurements came in with 1" BS up front, with the help of @jjvw and sending photos (Post #44). I put 1" in until I can cycle again but it's easy to add more with spring intact. 2" BS just touched the cup (not the jounce) to the perch at 1/4" short of full compression (and the tire cleared the fender). It was recommended that I go with a bit less to be use all of the shock.
This config has not been confirmed when full assembled since I wanted to put the new shocks on for a final cycle. But with the new shocks really close to the same length & travel as the 5100 I should be 'in there'.
SaulGoodman, You're making exercise the cranium.
Last edited:
You're certainly putting in the work. Guess I need to build a worksheet and follow your lead.
After putting the whole shaboom, front and rear, back together I come up with ride height of 17" front (down from 19") but the rear pretty much remained at 13" so still 5" lift on both ends. It has a slight forward rake to my eye and I like it just fine. Once the spare and some gear goes in it at least won't squat (220# springs).
@Ovaltine nailed it.
I have 7" of shaft up front on a 9.5" shock so I need to work to find the lengths that might be available out there, and at this point I don't really care which brand, except maybe Bilsteins.
So is this telling me I need a 2" longer front shock up front (24" currently) with equal or close in the travel parameter?
I agree with that.
You have about an inch more ride height than I do, so a Rancho RS55255 would give you 6 up and 5 down instead of my 5 up and 6 down. That's as perfect a selection as I could ask for, so I'd be looking at something similar to the 15.8-26.5" range offered by the Rancho. The KYB 565096 is close at 15.86-25.31 but it's shorter extended length would have you at a little under 4" of downtravel.
Reload.
I swear it settled after about an hour so I bounced on both front and rear bumpers and tried again. I'm posting the measurements then I'll take a shot at the maths.. lol.
Front Ride Height
Bilstein 24.0/14.5/9.5
Shock 20.5
Shaft 5-3/8"
Spring 16.5"
5-3/8 Up
4-1/8 Down
Rear Ride Height
Bilstein 25/16/9.5
Shock 21.5"
Shaft 5-7/8 L 6.25 R
Spring 13"
Call them both 6" I guess. 6" up x 3.5" down. The trackbar is in it's slot but not bolted. It shifted the rear diff a touch.
Last edited:
I'm just don't know the simple math to use for up/down travel.
By keeping the exposed shaft length equal to what it is on the current setup and subtracting that from the length of travel of the new shock is all I can come up with. Numbers are coming out way to close to 50/50 to believe I'm that lucky.
What the hell am I missing here.
Front
RS55255 10.73
Shaft @ ride 5.375 up travel
Remainder 5.355 down travel.
Rear
RS999005 10.35
Shaft @ ride 5.875 up travel
Remainder 4.475 down travel
At ride height, you have 19.875" between shock mounts. Here is how I arrived at this...
14.5" collapsed length
+ 5.375" exposed shaft at ride height
=====
19.875" between shock mounts at ride height (this is important. And you can verify this with a tape measure.)
9.5" total travel
- 5.375" exposed shaft at ride height
===
4.075" down travel
I'm just don't know the simple math to use for up/down travel.
By keeping the exposed shaft length equal to what it is on the current setup and subtracting that from the length of travel of the new shock is all I can come up with. Numbers are coming out way to close to 50/50 to believe I'm that lucky.
What the hell am I missing here.
Front
RS55255 10.73
Shaft @ ride 5.375 up travel
Remainder 5.355 down travel.
...
RS55255
15.8" collapsed length
10.73" total travel
26.53" extended length
19.875" between shock mounts at ride height (see above)
- 15.8" collapsed length
====
4.075" exposed shaft at ride height
10.73" total travel
- 4.075" exposed shaft at ride height
====
6.655" down travel
Do you see how I got this?
Last edited:
Something that help me keep track of this is to start with the collapsed length. Not that it directly matters here, but when we outboard, we build the mounts at full bump/full shock compression so that ride height brings the shock to half travel.
Also, formatting helps when writing the measurements down.
RS55255
15.8" collapsed length
10.73" total travel
26.53" extended length
This formatting is effectively a picture of the shock measurements as it exists on the jeep. Writing it this way helps visualize what the shock does.
You will also notice that I didn't specifically use the extended measurements to do any calculations.
Also, formatting helps when writing the measurements down.
RS55255
15.8" collapsed length
10.73" total travel
26.53" extended length
This formatting is effectively a picture of the shock measurements as it exists on the jeep. Writing it this way helps visualize what the shock does.
You will also notice that I didn't specifically use the extended measurements to do any calculations.
For the rear:
Bilstein
16.0 collapsed length
9.5" total travel
25" extended length
21.875 between shock mounts at ride height
16" collapsed length
—————-
5.875" exposed shaft at ride height
9.5" total travel
-5.875" exposed shaft at ride height
————-
3.625" down travel
I'll work optional shocks. Exposed shaft at ride height is up travel.
So the RS55255 is 4" up, 6.6" down? Flipped for upward bias right?
Thanks so much
That is what I came up with. And it matches my memory of them on mine. And why I decided to raise the front upper mount to bring them closer to 50/50 travel.
happy to help!
Similar threads
