Spring Part Number Explanation/FAQ

[blink9cd]

I'm interested in putting Rubicon take-off springs on my Willys. As I've started to learn about the process, I've found several threads discussing the best types of springs, comparing which ones exist, etc (like the sticky one at the top). However, I'm failing to find a thread that explains what the part numbers actually mean. I've found a few sites selling the springs but they don't seem to explain either.


For example, here's my part numbers with a '21 JLU Willys with SOT, 2.0T, automatic, plastic bumper, no towing:

Driver Front: 68253657AD
Passenger Front: 68253658AD

Driver Rear: 68253587AA
Passenger Rear: 68253588AA

Thus I'm trying to figure out how to parse this, for example:
68253657AD -> 6825 36 57 AD
(part start?) (6 front?) (57 - height?) (D - revision? Seems to change on front)

68253587AA -> 6825 35 87 AA
(part start?) (5 rear?) (87 - height?) (A - revision number? Doesn't seem to change)


Besides just knowing why, one reason is I've had a couple offers to sell me springs, and I found a local shop with a few sets of take-offs that said I could go through the sets and find ones that I'd want. I want to confidently know what I'm looking for before I blindly buy something.


My biggest questions:

1) Is higher "height" number what I'm looking for? (I see they go higher in the sticky -- I think it is from the threads)
2) Do the letters matter? Some front springs have an AB or AC after them? Are they older revision/a bad idea to buy?
3) With my springs, my passenger is one greater than driver (because of fuel tank?). I should preserve that, right? (I had one offer for a set where both fronts and both rears were the same)
4) Anything to watch for buying used? I realize a shop might not have data on how many miles (is a certain number of miles too many?)

If there's a link/thread out there that explains it in detail, feel free to just paste that in there and shame me. Thanks for any help!

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[Dyolfknip74]

I'm interested in putting Rubicon take-off springs on my Willys. As I've started to learn about the process, I've found several threads discussing the best types of springs, comparing which ones exist, etc (like the sticky one at the top). However, I'm failing to find a thread that explains what the part numbers actually mean. I've found a few sites selling the springs but they don't seem to explain either.


For example, here's my part numbers with a '21 JLU Willys with SOT, 2.0T, automatic, plastic bumper, no towing:

Driver Front: 68253657AD
Passenger Front: 68253658AD

Driver Rear: 68253587AA
Passenger Rear: 68253588AA

Thus I'm trying to figure out how to parse this, for example:
68253657AD -> 6825 36 57 AD
(part start?) (6 front?) (57 - height?) (D - revision? Seems to change on front)

68253587AA -> 6825 35 87 AA
(part start?) (5 rear?) (87 - height?) (A - revision number? Doesn't seem to change)


Besides just knowing why, one reason is I've had a couple offers to sell me springs, and I found a local shop with a few sets of take-offs that said I could go through the sets and find ones that I'd want. I want to confidently know what I'm looking for before I blindly buy something.


My biggest questions:

1) Is higher "height" number what I'm looking for? (I see they go higher in the sticky -- I think it is from the threads)
2) Do the letters matter? Some front springs have an AB or AC after them? Are they older revision/a bad idea to buy?
3) With my springs, my passenger is one greater than driver (because of fuel tank?). I should preserve that, right? (I had one offer for a set where both fronts and both rears were the same)
4) Anything to watch for buying used? I realize a shop might not have data on how many miles (is a certain number of miles too many?)

If there's a link/thread out there that explains it in detail, feel free to just paste that in there and shame me. Thanks for any help!

The letters at the end are revisions. As for the rest of the numbers, who knows. Just look for a set of Rubicon springs from something with a 2.0 or a 3.8. They're all pretty close, if not the same. It's only the diesels and 4Xe that are markedly different.

At the end of the day, it's a take off suspension that at best should be like $200. Install it and see how it goes.

 

[Headbarcode]

I'm interested in putting Rubicon take-off springs on my Willys. As I've started to learn about the process, I've found several threads discussing the best types of springs, comparing which ones exist, etc (like the sticky one at the top). However, I'm failing to find a thread that explains what the part numbers actually mean. I've found a few sites selling the springs but they don't seem to explain either.


For example, here's my part numbers with a '21 JLU Willys with SOT, 2.0T, automatic, plastic bumper, no towing:

Driver Front: 68253657AD
Passenger Front: 68253658AD

Driver Rear: 68253587AA
Passenger Rear: 68253588AA

Thus I'm trying to figure out how to parse this, for example:
68253657AD -> 6825 36 57 AD
(part start?) (6 front?) (57 - height?) (D - revision? Seems to change on front)

68253587AA -> 6825 35 87 AA
(part start?) (5 rear?) (87 - height?) (A - revision number? Doesn't seem to change)


Besides just knowing why, one reason is I've had a couple offers to sell me springs, and I found a local shop with a few sets of take-offs that said I could go through the sets and find ones that I'd want. I want to confidently know what I'm looking for before I blindly buy something.


My biggest questions:

1) Is higher "height" number what I'm looking for? (I see they go higher in the sticky -- I think it is from the threads)
2) Do the letters matter? Some front springs have an AB or AC after them? Are they older revision/a bad idea to buy?
3) With my springs, my passenger is one greater than driver (because of fuel tank?). I should preserve that, right? (I had one offer for a set where both fronts and both rears were the same)
4) Anything to watch for buying used? I realize a shop might not have data on how many miles (is a certain number of miles too many?)

If there's a link/thread out there that explains it in detail, feel free to just paste that in there and shame me. Thanks for any help!

It's the last two numbers that matter most. Ther refer to spring rate. The higher the number, the more resistant to weight they will be before sagging. The higher the number you swap to, the higher your Jeep will sit. You have the 57/58 and 87/88 combo. Due to my ordering my JLUR to be built with hardtop, steel bumpers, and the tow package, mine got 61/62 and 91/92.

The smaller number always goes on the drivers side, as you were right, it's to offset the fuel tank on the passenger rear frame rail.

 

[lalalofsky]

It's the last two numbers that matter most. Ther refer to spring rate. The higher the number, the more resistant to weight they will be before sagging. The higher the number you swap to, the higher your Jeep will sit. You have the 57/58 and 87/88 combo. Due to my ordering my JLUR to be built with hardtop, steel bumpers, and the tow package, mine got 61/62 and 91/92.

The smaller number always goes on the drivers side, as you were right, it's to offset the fuel tank on the passenger rear frame rail.

When I put rubicon take off springs and shocks on my jeep My spring numbers were exactly this 61/62 and 91/92. my 2.0t 4 door lifted just shy of 2 inches.

 

[blink9cd]

The letters at the end are revisions. As for the rest of the numbers, who knows. Just look for a set of Rubicon springs from something with a 2.0 or a 3.8. They're all pretty close, if not the same. It's only the diesels and 4Xe that are markedly different.

At the end of the day, it's a take off suspension that at best should be like $200. Install it and see how it goes.

So you think the revisions don't matter? For example, if I find a 61AB/62B combo for the front, is that "inferior" to a 61AD/62AD combo? If so, what about a 61AC/62AC compared to something like a lower spring rate but higher revision, say 60AD/61AD?

I ask because I've seen various part numbers posted with different revisions on the forums. The shop I called said they had several sets and I can dig through all of them to get what I specifically want.

 

[Dyolfknip74]

So you think the revisions don't matter? For example, if I find a 61AB/62B combo for the front, is that "inferior" to a 61AD/62AD combo? If so, what about a 61AC/62AC compared to something like a lower spring rate but higher revision, say 60AD/61AD?

I ask because I've seen various part numbers posted with different revisions on the forums. The shop I called said they had several sets and I can dig through all of them to get what I specifically want.

Yes, revisions matter. For instance, a lot of the early kits had springs that bowed a lot outwards. They fixed that with newer kits.

 

[Headbarcode]

When I put rubicon take off springs and shocks on my jeep My spring numbers were exactly this 61/62 and 91/92. my 2.0t 4 door lifted just shy of 2 inches.

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.

 

[blink9cd]

It's the last two numbers that matter most. Ther refer to spring rate. The higher the number, the more resistant to weight they will be before sagging. The higher the number you swap to, the higher your Jeep will sit. You have the 57/58 and 87/88 combo. Due to my ordering my JLUR to be built with hardtop, steel bumpers, and the tow package, mine got 61/62 and 91/92.

The smaller number always goes on the drivers side, as you were right, it's to offset the fuel tank on the passenger rear frame rail.

Thanks for confirming the main numbers are the spring rate. It sounds like with your config what you have is the highest gas engine combo. If I found that exact combo, it seems like both are 4 steps up on my front and back (57 to 61, 87 to 91) and would be the best set for me.

But I've seen some people post they got say 61/62 and 90/91 for example. That would be a step up of 4 on the front but 3 on back for me. Is that a bad thing, like not keeping the passenger one step higher then the driver, or not matter? Say if I only found 90/91 in the box for rears, even if 62 was available would it then make sense to do 60/61 to keep it symmetric? Or is highest I can find for front and rear independently always preferable?

 

[Headbarcode]

Thanks for confirming the main numbers are the spring rate. It sounds like with your config what you have is the highest gas engine combo. If I found that exact combo, it seems like both are 4 steps up on my front and back (57 to 61, 87 to 91) and would be the best set for me.

But I've seen some people post they got say 61/62 and 90/91 for example. That would be a step up of 4 on the front but 3 on back for me. Is that a bad thing, like not keeping the passenger one step higher then the driver, or not matter? Say if I only found 90/91 in the box for rears, even if 62 was available would it then make sense to do 60/61 to keep it symmetric? Or is highest I can find for front and rear independently always preferable?

The recipe for the highest spring rates on a factory built Rubicon, is one that was ordered with a hardtop, steel bumpers, and the tow package. I've also seen that combo assembled with 90/91 rear springs. I don't think it makes a big difference, one way or the other, and same thoughts on the front 4 jump and rear 3 jump that you mentioned.

Have you dug around in the marketplace? There's a slew of Rubicon takeoffs to be found there. Check both the suspension and the pay it forward sections, as some want a bit of money and others just want to see someone else make use of them.

 

[Some Random Guy]

My takeoff springs are matched in the rear. I haven’t installed them yet, so we’ll see what happens. Hopefully tomorrow or Saturday.
68413671AA

 

[blink9cd]

Yes, revisions matter. For instance, a lot of the early kits had springs that bowed a lot outwards. They fixed that with newer kits.

Ah ok gotcha. That does not seem like something I'd want to experience! My JLU was delivered in Oct with ADs, so I'm guessing I probably have the newest revisions unless '22s have newer ones.

Sounds like I wouldn't want to regress revisions for spring rate, so end result I should be looking for ADs. I don't think I've seen rears posted that aren't AAs, perhaps they never had issues?

Summary take away (unless someone corrects me): letters at the end are revisions, with farther along the alphabet newer. And interpretation is higher letter the better due to previous manufacturing issues.

 

[Dyolfknip74]

Ah ok gotcha. That does not seem like something I'd want to experience! My JLU was delivered in Oct with ADs, so I'm guessing I probably have the newest revisions unless '22s have newer ones.

Sounds like I wouldn't want to regress revisions for spring rate, so end result I should be looking for ADs. I don't think I've seen rears posted that aren't AAs, perhaps they never had issues?

Summary take away (unless someone corrects me): letters at the end are revisions, with farther along the alphabet newer. And interpretation is higher letter the better due to previous manufacturing issues.

I haven't heard of the bowing happening at all since last year.

 

[blink9cd]

The recipe for the highest spring rates on a factory built Rubicon, is one that was ordered with a hardtop, steel bumpers, and the tow package. I've also seen that combo assembled with 90/91 rear springs. I don't think it makes a big difference, one way or the other, and same thoughts on the front 4 jump and rear 3 jump that you mentioned.

Have you dug around in the marketplace? There's a slew of Rubicon takeoffs to be found there. Check both the suspension and the pay it forward sections, as some want a bit of money and others just want to see someone else make use of them.

Gotcha, in summary sounds like I should be looking for the highest spring rates independently on front and back, and not to worry about relative differences.

I have started to look on the marketplace here... That's actually what started all my questioning as to what I was actually looking at haha. Of course it's a little tough with how dispersed this forum is to find someone close with a right set. I had two offers from my local club but they didn't work so far (one set were JKs, another set for setups that have matching front and rears). They also led me to the tip of asking local shops, which of course led to me wanting to know how to parse the data.

 

[blink9cd]

My takeoff springs are matched in the rear. I haven’t installed them yet, so we’ll see what happens. Hopefully tomorrow or Saturday.
68413671AA

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.

 

[Headbarcode]

Gotcha, in summary sounds like I should be looking for the highest spring rates independently on front and back, and not to worry about relative differences.

I have started to look on the marketplace here... That's actually what started all my questioning as to what I was actually looking at haha. Of course it's a little tough with how dispersed this forum is to find someone close with a right set. I had two offers from my local club but they didn't work so far (one set were JKs, another set for setups that have matching front and rears). They also led me to the tip of asking local shops, which of course led to me wanting to know how to parse the data.

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.

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