TJ Shock & Spring Specification Resource Thread

Below you'll find specifications for most of the known aftermarket shocks and springs for our TJs. This should be very helpful for people who are looking to put together a suspension system that works well together. Thanks to @jjvw for providing this info.


This is great. Here was my feeble attempt to do something similar for options when keeping it stock for an SE. Because, you know, everyone needs that information ...
 
Yea, I wrote to him recently with a question, and he mentioned that 2020 was quite a year for him so hadn't been on much. He came back on for a bit after that, and hopefully he'll be around more. I've benefitted from all his 2.5 information. And of course I need him to stick around to carry the brunt of the 2.5 bashing for me. ;-)

Haha, well good to know he's still around. He used to be one of the more active members on here but he disappeared some years ago.

Hey man, a 2.5 is a damn good excuse to build a trail rig :LOL:
 
You will probably find it difficult to get spring rates for any of the dual rate spring manufacturers as they consider this proprietary information including Currie/RockJock.
https://www.rockjock4x4.com/CE-9132FP
Screenshot_20210331-102151_Chrome.jpg
 
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Can anyone please help me understand or at least point me into the right direction why the Rancho RS55128 (Front) is the right shock to use in a 2"-2.5" lift?

Compared to the stock TJ Front Shock it has 13.05 vs 13.00 compressed length, and 21.03 vs 20.50 extended length.

Is it wrong to assume that you would need a shock roughly 2-2.5" longer than the stock one?
 
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Can anyone please help me understand or at least point me into the right direction why the Rancho RS55128 (Front) is the right shock to use in a 2"-2.5" lift?

Compared to the stock TJ Front Shock it has 13.05 vs 13.00 compressed length, and 21.03 vs 20.50 extended length.

Is it wrong to assume that you would need a shock roughly 2-2.5" longer than the stock one?
55128 Rancho and a 2” Procomp 170in/lb spring.
It is the correct shock for 2-2.5” of lift

73631EE9-C239-42CA-8084-7EF984C214FA.jpeg
 
You will probably find it difficult to get spring rates for any of the dual rate spring manufacturers as they consider this proprietary information including Currie/RockJock.
I think it’s more of; they don’t know.
A progressive or dual rate spring averages depending on how much it’s being compressed.
 
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Anyone have any experience with the Fox 985-26-108 and 985-26-112 (2.0 performance series, reservoir with damping adjuster) for a 3" lift
 
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Can Rancho RS55239 or RS55128 be used as rear shocks as well?

I thought they were front shocks. Why are they mentioned in the rear shocks section?
 
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I don't see mine listed either, @Chris . Here are my Fox remote resis:

FRONT: Fox 985-24-109, 10.6" travel, 16.2" collapsed, 26.8" extended

REAR: Fox 985-24-113, 9.6" travel, 15.35" collapsed, 24.95" extended
 
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@Chris I've noticed some minor inconsistencies in some Rancho RS5000x shock lengths.

RS55240 - Compressed: 12.76, Travel: 7.28, Extended: 20.4
RS55241 - Compressed: 13.51, Travel: 8.16, Extended: 21.67
RS55255 - Compressed: 15.8, Travel: 10.73, Extended: 26.53
RS55256 - Compressed: 15.01, Travel: 9.66, Extended: 24.67

By Ranchos Site: https://www.gorancho.com/products/s...shock-absorber/?find=2004-jeep-tj-4wd-4013428

Good catch. For how popular these are, it's good to get the info right.

I haven't looked closely, so maybe the answer is obvious, but does this answer your previous question about which Rancho shock is right for a 2–2.5" lift? I always hear that the Ranchos run long, but when I installed mine, I found them to be only a fraction of an inch longer than stock.
 
Good catch. For how popular these are, it's good to get the info right.

I haven't looked closely, so maybe the answer is obvious, but does this answer your previous question about which Rancho shock is right for a 2–2.5" lift? I always hear that the Ranchos run long, but when I installed mine, I found them to be only a fraction of an inch longer than stock.

Unfortunately I bought RS55128/RS55240. They are not the right ones for my case. I am most likely going to replace them with RS55239/RS55241

That's because OME Light Duty 2" Springs (932/941) gave me around 3" front lift, and around 2.5" rear lift. (it seems that 4-cylinders are extra light!)

So, I had the following results (Real measurements)
RS55128: 5.7" up travel and 2.28" down travel
RS55240: 5.44" up travel, 1.84" down travel

With some maths I calculated that with RS55239/RS55241 I will have the following:
RS55239: 4.32" up travel, 5.09" down travel
RS55241: 4.69" up travel, 3.47" down travel

It is clear that the longer ones are closer to 50 50 ratio, since the shorter ones are giving me a very small amount of down travel. It doesn't seem right.

I am also considering adding a small spacer on front, which will give an almost perfect 50 50 on front shock travel.

*RS55128 (Front) seems to be perfect for around 1-1.5" of lift
** RS55239 (Front) seems to be perfect for around 3-3.5" of lift
*** RS55240 (Rear) seems to be perfect for around 0.5-1" of lift
**** RS55241 (Rear) seems to be perfect for around 2" lift
***** When I say perfect, I mean they seem to have a nearly perfect 50 50 ratio of up travel and down travel.
 
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Unfortunately I bought RS55128/RS55240. They are not the right ones for my case. I am most likely going to replace them with RS55239/RS55241

That's because OME Light Duty 2" Springs (932/941) gave me around 3" front lift, and around 2.5" rear lift. (it seems that 4-cylinders are extra light!)

So, I had the following results (Real measurements)
RS55128: 5.7" up travel and 2.28" down travel
RS55240: 5.44" up travel, 1.84" down travel

With some maths I calculated that with RS55239/RS55241 I will have the following:
RS55239: 4.32" up travel, 5.09" down travel
RS55241: 4.69" up travel, 3.47" down travel

It is clear that the longer ones are closer to 50 50 ratio, since the shorter ones are giving me a very small amount of down travel. It doesn't seem right.

I am also considering adding a small spacer on front, which will give an almost perfect 50 50 on front shock travel.

* RS55239 seems to be perfect for around 3-3.5" of lift
** RS55241 seems to be perfect for around 2" lift
*** RS55128 seems to be perfect for around 1-1.5" of lift
**** RS55240 seems to be perfect for around 0.5-1" of lift

Thanks for this. Yep, I remember asking, in a different thread, what amount of lift you got, since I was curious how the weight of the 2.5 would affect it. This is really helpful, and I hope Chris can update the original post with it. I'll also link this post to the "Stock SE" thread.

Edit: Could you add notes, to your * bullet points, about which are for front and rear? Or, I guess it doesn't really matter, because you're just providing the info based on the difference in max length, compared to stock, right?
 
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Thanks for this. Yep, I remember asking, in a different thread, what amount of lift you got, since I was curious how the weight of the 2.5 would affect it. This is really helpful, and I hope Chris can update the original post with it. I'll also link this post to the "Stock SE" thread.

Edit: Could you add notes, to your * bullet points, about which are for front and rear? Or, I guess it doesn't really matter, because you're just providing the info based on the difference in max length, compared to stock, right?
I was curious too about how much lift would the OME Light Duty would give me. If I would have to use spacers, or if I would have to replace them with OME HD. Finally, it gave me more than enough for my 31" tires.

I added notes to the * bullet points. Obviously they apply for both 4-cylinder, 6-cylinder or any other engine. I am talking about actual final lift size.

I'll also link this post to the "Stock SE" thread.
I am happy to gather every info possible for our light TJs.
 
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