Rear Spring Relocation Without Adding Height?

jjvw said:
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
Click to expand...

jjvw said:
does.

You will also notice that I didn't specifically use the extended measurements to do any calculations.
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Nice.

Yup, just the collapsed length + total travel.
 
jjvw said:
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!
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I'll hunt for a shock that will get me closer w/o moving shit around. Will be good exercise.
 
Edit: this post is an incorrect calculation.

Rancho RS999005 Rear

17.63 collapsed
+ 5.375 exposed (up travel)
———-
23.0” between shock mounts at ride height

10.35” total travel
- 5.375” exposed shaft at ride height
————-
4.975"

5.375" Up Travel
4.975" Down Travel

I’m liking this.
 
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NOTNSUV said:
Feeling like when I first tied my own shoes. :ROFLMAO::ROFLMAO::ROFLMAO:
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Just make sure, when calculating for other shocks, you are using your existing measurements between shock mounts. That number does not change unless you change the springs (or change the pinion angles).
 
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jjvw said:
Just make sure, when calculating for other shocks, you are using your existing measurements between shock mounts. That number does not change unless you change the springs (or change the pinion angles).
Click to expand...
So my last calculation was off because I kept the shaft exposure the same and changed the distance between shock mounts.

Got it!
 
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NOTNSUV said:
So my last calculation was off because I kept the shaft exposure the same and changed the distance between shock mounts.
Got it!
Click to expand...
Notice that different shocks have different measurements. The exposed shaft length changes between different shocks because the collapsed length changes. This affects how much exposed shaft a given shock provides on your rig. The only constant is the measurement between your shock mounts.

This is a reason why we can't reliably select a shock based on lift height.
 
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jjvw said:
Notice that different shocks have different measurements. The exposed shaft length changes between different shocks because the collapsed length changes. This affects how much exposed shaft a given shock provides on your rig. The only constant is the measurement between your shock mounts.

This is a reason why we can't reliably select a shock based on lift height.
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Will BPE change mount to mount distance? Is there a specific BPE that's preferred (I do a search)
Will that broaden the shock selection?
KYB shows S1 for the barpin it appears. The other end is all over the map. E3(51.6x82x0)
E3(68.5x95x0)E2(12×36)
 
NOTNSUV said:
Will BPE change mount to mount distance? Is there a specific BPE that's preferred (I do a search)
Will that broaden the shock selection?
KYB shows S1 for the barpin it appears. The other end is all over the map. E3(51.6x82x0)
E3(68.5x95x0)E2(12×36)
Click to expand...
A bar pin eliminator will typically decrease the distance between mounts by ~ 1”. This will decrease the up travel and turn it into down travel since the amount of shaft showing will be decreased. You could also use metal standoffs of whatever length you needed (within reason) on the front bottom mount to do essentially the same thing. If this puts a certain shock in the middle of its travel, it’s not a bad idea to think of going this way. I believe @jjvw used to run his fronts like this.
 
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Ovaltine said:
A bar pin eliminator will typically decrease the distance between mounts by ~ 1”. This will decrease the up travel and turn it into down travel since the amount of shaft showing will be decreased. You could also use metal standoffs of whatever length you needed (within reason) on the front bottom mount to do essentially the same thing. If this puts a certain shock in the middle of its travel, it’s not a bad idea to think of going this way. I believe @jjvw used to run his fronts like this.
Click to expand...

I used to run a raised front lower mount which allowed me to recover about an inch of unused uptravel on the shocks I had at the time. It's a good trick to understand, but is only useful with certain combinations of ride height, shock size and tire size.
 
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Tough search for anything close to 50/50.
Went to Savvy to look at their Fox offerings.

TJF4 15.55/25.15/9.6 (TJF3 has identical specs on the website so I sent an email)
Front
19.875' my mount - mount
-15.55 collapsed
————-
4.325 Shaft (up travel)

9.6 total travel
-4.325
—————
5.275 down travel

If these calculations are correct it's about as close as anything so far.

Rear
TJR4 15.65/24.75/9.1
21.5"
-15.65
—————
5.85" shaft showing (up travel)

9.1" total travel
-5.855"
————
3.25 down travel
 
Does anyone have an explanation as to why his mount to mount measures 19.875” with a 4.5” lift but mine measures 20.25” with 3” of lift?
 
Ovaltine said:
Does anyone have an explanation as to why his mount to mount measures 19.875” with a 4.5” lift but mine measures 20.25” with 3” of lift?
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Operator error. Finally got someone to hold one end of the damn tape and get the flashlight out of my mouth so I can see.
Coming up with 21" mount - mount. That's at the bottom of the upper shock pocket/top of shock rubber to the barpin on the bottom. I might well have been holding the tape on the shoulder I use to measure exposed shaft length. DANG!

So I'm going to restart the calculations and ponder which shock meets or gets close to the criteria and make a choice. The one below, if accurate is definitely a contender for the front and was right in front of my face.

Chagrin. :sick:

RS55255
21.0 Mt - Mt at ride height
-15.8 Collapsed
———-
5.20 shaft exposed (up travel)

10.73 Total Travel
- 5.20 shaft exposed
————
5.53 down travel
 
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Now that I have some numbers to work with I'm finding some shocks that get near 50/50.
Do I need to stay under 11" total travel.
For example:
SJ BM Rear B8563 16.05/11.28/27.33 6" up 5.28" down.

After checking the forum list these are closest I can find so far:

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

The rear seems to be the challenge. I think it was @freedom_in_4low commented recently about the same issue but I'll be danged if I can find the post. He was talking about biting the bullet and going with 2 different brand shocks.
 
NOTNSUV said:
Now that I have some numbers to work with I'm finding some shocks that get near 50/50.
Do I need to stay under 11" total travel.
For example:
SJ BM Rear B8563 16.05/11.28/27.33 6" up 5.28" down.

After checking the forum list these are closest I can find so far:

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

The rear seems to be the challenge. I think it was @freedom_in_4low commented recently about the same issue but I'll be danged if I can find the post. He was talking about biting the bullet and going with 2 different brand shocks.
Click to expand...
Eventually, you just gotta pick something and make it work.
 
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NOTNSUV said:
Now that I have some numbers to work with I'm finding some shocks that get near 50/50.
Do I need to stay under 11" total travel.
For example:
SJ BM Rear B8563 16.05/11.28/27.33 6" up 5.28" down.

After checking the forum list these are closest I can find so far:

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

The rear seems to be the challenge. I think it was @freedom_in_4low commented recently about the same issue but I'll be danged if I can find the post. He was talking about biting the bullet and going with 2 different brand shocks.
Click to expand...

I've posted it a few times, including in this thread I think yesterday. I don't know if my situation is unique but for whatever reason between KYB, Fox ifp, and Skyjacker there's nothing that fits both axles as well as the Ranchos.

Those rs55332 are super long. I run rs55256 which is only 15.01 compressed and I have around 2.5" of bump stop back there just for the shock...but extended is only 24.67 so that puts your downtravel in the 3s.
 
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freedom_in_4low said:
I've posted it a few times, including in this thread I think yesterday. I don't know if my situation is unique but for whatever reason between KYB, Fox ifp, and Skyjacker there's nothing that fits both axles as well as the Ranchos.

Those rs55332 are super long. I run rs55256 which is only 15.01 compressed and I have around 2.5" of bump stop back there just for the shock...but extended is only 24.67 so that puts your downtravel in the 3s.
Click to expand...
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 5.45 U x 5.83 Down

Same travel as the RS55332 but 0.83 shorter compressed and 0.92 shorter extended.
..or I could go KYB front 565096 15.86/25.31/9.45 For 5.13 U x 4.31 Down. At least have red/black on both ends.. lol.
 
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