Spring Part Number Explanation/FAQ

[Some Random Guy]

What are those from? Very different serial numbers than mine or what I've seen. Makes me curious how to decode it.

From what I've seem so far I would've guessed different serial beginning, fronts, very high spring rate, first revision. Perhaps a diesel? But maybe all the numbers after the beginning don't interpret in how I think they would.

They’re from a shop dumpster, lol. I was also expecting different part numbers and originally went past them. I know it was from a 4 door Rubicon, but am starting to wonder if it was a 4xe or something weird. Free.99 though, so I’ll try them. Worst case I find out how much more spring I need to use my longer shocks (falcon sp2 2.1 2-3.5” fronts, rocksports in rear).

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[blink9cd]

It's definitely worth pearl diving through that shops takeoffs to see if you can luck out, now that you no what to zero in on.

Yep exactly what I'm thinking. And under no obligation to buy anything if I don't find a set that matches what I want.

I think I know the answer to this now, but just to be sure: there's no distinction between driver and passenger springs in either the front or back, right? Meaning there's nothing special that distinguishes them as driver/passenger (what's on the ends or something like that).

For example, for a given rear 91 that I find in a box, it could be a 90/91 combo where it serves passenger side if I find a 90 to pair with it, or the same 91 spring could function driver in a 91/92 combo if I find that?

 

[blink9cd]

They’re from a shop dumpster, lol. I was also expecting different part numbers and originally went past them. I know it was from a 4 door Rubicon, but am starting to wonder if it was a 4xe or something weird. Free.99 though, so I’ll try them. Worst case I find out how much more spring I need to use my longer shocks (falcon sp2 2.1 2-3.5” fronts, rocksports in rear).

Lol dumpster, but yeah can't beat free. From all the examples I saw it seemed like for springs starting with 6825, after the 3 comes a 5/6 which seems to always correlate Rear/Front. But yours has a 6 and when I google your part number is does say Rear Coil Spring, sometimes RHD...what I saw could just be a coincidence. I think the 6841 does seem to matter quite a bit for decoding what's going on.

 

[lalalofsky]

From others reports of doing that swap, that is about the maximum gain in height from Rubi takeoffs. The guy that I gave mine to said that he saw about an 1.5", but he already had added steel bumpers beforehand.

Good point. I didnt have any added weight when i did that. After adding a winch And steel front bumper and a heavy 34.4 spare it pushes me down to around 1.5 inches

 

[lalalofsky]

Yep exactly what I'm thinking. And under no obligation to buy anything if I don't find a set that matches what I want.

I think I know the answer to this now, but just to be sure: there's no distinction between driver and passenger springs in either the front or back, right? Meaning there's nothing special that distinguishes them as driver/passenger (what's on the ends or something like that).

For example, for a given rear 91 that I find in a box, it could be a 90/91 combo where it serves passenger side if I find a 90 to pair with it, or the same 91 spring could function driver in a 91/92 combo if I find that?

I do believe the springs are corner specific. So if you two 90s for the rear one side will sag. The different spring rates in each corner are important because in each corner the weight or in your case, the expected weight will be different. Since your gas tank is on the passenger side of the car, the spring rates are going to be higher in order to support that extra weight and eliminate excessive body rake.

 

[lalalofsky]

@AnnDee4444 worked tirelessly on this suspension chart. This might help you on your coil journey

https://www.jlwranglerforums.com/fo...gs-suspension-information-chart-matrix.66591/

 

[blink9cd]

I do believe the springs are corner specific. So if you two 90s for the rear one side will sag. The different spring rates in each corner are important because in each corner the weight or in your case, the expected weight will be different. Since your gas tank is on the passenger side of the car, the spring rates are going to be higher in order to support that extra weight and eliminate excessive body rake.

That makes sense to me based on weight distribution. But to make sure it's clear what I'm asking and that I understand it correctly: since a given 91 has a specific serial number, say 68253591AA, and nothing in that serial distinguishes driver vs passenger (that I can tell), my guess is that it can't be location specific since there's nothing else to distinguish it from any other 91 with that serial number when you buy it from Mopar, etc (and if there was something different about it, it'd be in the serial number).

And thus the way this is handled for a specific Jeep is you buy different spring serial numbers (and thus spring rates). So if you had a 92 laying around, the 91 functions as driver, or instead if you come across a 90 the 91 functions as passenger. And thus a given 91 springs functions as either side, it just depends on how it's paired.

 

[blink9cd]

@AnnDee4444 worked tirelessly on this suspension chart. This might help you on your coil journey

https://www.jlwranglerforums.com/fo...gs-suspension-information-chart-matrix.66591/

This was one of the first posts I found (being a sticky really helped). It's been very useful for me to understand the ranges and configs. I think I'm trying to answer a different (and smaller!) question: what does everything in the serials actually decode to, so when I see a spring serial I really know what's going on. Partly for the record, but mostly so I don't buy something I don't understand.

 

[AnnDee4444]

This was one of the first posts I found (being a sticky really helped). It's been very useful for me to understand the ranges and configs. I think I'm trying to answer a different (and smaller!) question: what does everything in the serials actually decode to, so when I see a spring serial I really know what's going on. Partly for the record, but mostly so I don't buy something I don't understand.

Unfortunately I don't think the part numbers mean anything of value.

I'm sure somewhere a Jeep employee or whoever they have manufacture has a spreadsheet that lists all the values. Like this: https://www.moog-suspension-parts.com/universal_coil_springs.asp

 

[lalalofsky]

That makes sense to me based on weight distribution. But to make sure it's clear what I'm asking and that I understand it correctly: since a given 91 has a specific serial number, say 68253591AA, and nothing in that serial distinguishes driver vs passenger (that I can tell), my guess is that it can't be location specific since there's nothing else to distinguish it from any other 91 with that serial number when you buy it from Mopar, etc (and if there was something different about it, it'd be in the serial number).

And thus the way this is handled for a specific Jeep is you buy different spring serial numbers (and thus spring rates). So if you had a 92 laying around, the 91 functions as driver, or instead if you come across a 90 the 91 functions as passenger. And thus a given 91 springs functions as either side, it just depends on how it's paired.

I suppose that might work. I cant really think of a reason anyone would be selling just 1 or 2 coils off a rubicon. I guess if youre going to do this then I’d recommend making sure if it comes with a 60/61 and 90/91 just an random example, and you wanted 91/92 instead, youd probably want to compliment those numbers. that being said I think as far as quality of ride goes, i would just stick to the 4 coils That come as a group rather than trying to play around with the numbers. They are designed to work together and thus altering the configuration too much will spoil your hard work.

 

[AnnDee4444]

Unfortunately I don't think the part numbers mean anything of value.

I'm sure somewhere a Jeep employee or whoever they have manufacture has a spreadsheet that lists all the values. Like this: https://www.moog-suspension-parts.com/universal_coil_springs.asp

Expanding on this: it is probably possible to compare springs with others on this forum by documenting the following (which I am not going to attempt):

• wire diameter - there are probably only a few used for ease of manufacturing (assuming same material for all springs)
• number of coil wraps - need to come up with a diagram of where to start/stop, possibly in total degrees of wire.
• free length - this is the most difficult to achieve since an old spring will be shorter than a new one.

The same wire diameter & coil wraps = same rate. Less wraps or thicker diameter = higher rate. Assuming same rate, free length is somewhat proportional to ride height.

And after all that, I really think it's just easier to add spacers.

 

[Headbarcode]

Yep exactly what I'm thinking. And under no obligation to buy anything if I don't find a set that matches what I want.

I think I know the answer to this now, but just to be sure: there's no distinction between driver and passenger springs in either the front or back, right? Meaning there's nothing special that distinguishes them as driver/passenger (what's on the ends or something like that).

For example, for a given rear 91 that I find in a box, it could be a 90/91 combo where it serves passenger side if I find a 90 to pair with it, or the same 91 spring could function driver in a 91/92 combo if I find that?

Yes, if you had a 90/91, the 91 would go on the passenger side. If that same 91 was paired with a 92, it would than go on the driver side. Smaller # always goes driver and larger # always goes passenger.

I hope you find the right oyster!

 

[Some Random Guy]

Unfortunately I don't think the part numbers mean anything of value.

I'm sure somewhere a Jeep employee or whoever they have manufacture has a spreadsheet that lists all the values. Like this: https://www.moog-suspension-parts.com/universal_coil_springs.asp

Yeah, part numbers need to be primary keys in tables. They might start with a method, but eventually that falls apart. Even if they’re supposed to be compound keys, the constant revisions will eventually break down in a company this large. Hard to read too far into them, as you noted.

 

[blink9cd]

Yes, if you had a 90/91, the 91 would go on the passenger side. If that same 91 was paired with a 92, it would than go on the driver side. Smaller # always goes driver and larger # always goes passenger.

I hope you find the right oyster!

Ok cool I think that makes sense to me. I hope so too, I'm gonna check them out tomorrow.

I suppose that might work. I cant really think of a reason anyone would be selling just 1 or 2 coils off a rubicon. I guess if youre going to do this then I’d recommend making sure if it comes with a 60/61 and 90/91 just an random example, and you wanted 91/92 instead, youd probably want to compliment those numbers. that being said I think as far as quality of ride goes, i would just stick to the 4 coils That come as a group rather than trying to play around with the numbers. They are designed to work together and thus altering the configuration too much will spoil your hard work.

Mostly thought it's useful to understand how they work somewhat fundamentally (cause for example, what if you somehow broke one spring, or something dumb happened while you had them out and you lost it, couldn't you just order that one spring from Mopar with the same serial and it should just slot in there, right?). But overall I agree with you, it makes the most sense on buying them together as you know they should work together. I personally hope it's not a literal box of springs all mixed together, but instead multiple grouped sets

 

[blink9cd]

Unfortunately I don't think the part numbers mean anything of value.

I'm sure somewhere a Jeep employee or whoever they have manufacture has a spreadsheet that lists all the values. Like this: https://www.moog-suspension-parts.com/universal_coil_springs.asp

Wow that site is super detailed! I agree, there's gotta be a Jeep engineer with that somewhere...it would be useful, but probably more detail than I need. At least from looking at your table, it seems the part numbers do have value in the sense of capturing relative differences of rates/revisions and what you'll get out of them, even if say "87" vs "92" it not a meaningful measure on its own. And thus being able to decode that is certainly a step better than having to ask "what year? what kind of options did this Jeep have?" when you're looking at each spring.

Expanding on this: it is probably possible to compare springs with others on this forum by documenting the following (which I am not going to attempt):

• wire diameter - there are probably only a few used for ease of manufacturing (assuming same material for all springs)
• number of coil wraps - need to come up with a diagram of where to start/stop, possibly in total degrees of wire.
• free length - this is the most difficult to achieve since an old spring will be shorter than a new one.

The same wire diameter & coil wraps = same rate. Less wraps or thicker diameter = higher rate. Assuming same rate, free length is somewhat proportional to ride height.

And after all that, I really think it's just easier to add spacers.

Just wanted to say that's interesting to learn how to break them down!

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