Confirmed: Rubicon Front Springs 340/ 343 are 1" Taller than Sport S Max Tow

[ShadowsPapa]

Has anyone done a weight test on the springs? Like put it into a rate checker, squished it down 1" and see what the load is between the pairs? Then coilbind the soft section of the spring and then test the progressive rate?

I'm thinking that there are "pairs" of springs with different part numbers, but the same spring rate. Because everything is codified, tracked, numbered, etc. Each part needs it's own identifiable part number.

It would make sense that the Rubicon gets special springs for off-road use. Same with Mojave. Sport/Sport S/Willys get general springs. Max tow gets springs for heavy loads. Overland a spring that focuses on road ride. So those combinations would eventually add up, but it's not like each individual spring has a different rate.

The Quadratec page for JT springs list 26 springs. That's 13 pairs to divvy amongst 10 trims and 2 engine choices over 2 model years.

And my spring part #s aren't even listed yet. 68506362AA (L) & 68506363AA (R).

Have you actually compared the springs side to side? I have. PAIR of Rubicon springs - one side has 9 coils and is slightly shorter, the other has 7, spaced differently.
They have different rates, different numbers of coils, and I bet if I went through the work of pulling them off the high shelf and unpacking/unboxing them again and measuring the wire size, I'd see a difference. Not always, but some.

If they are the same, explain why one truck gets a 339 and a 340 with 340 on the right and another gets a 340 and a 343 with the 340 on the left.
Even 50 years ago they were very different and you had to buy based on the options and the side of the vehicle.
Rubicon springs aren't different for "off-road use". They are different for the height and weight of the vehicle.

Spring Rate refers to the amount of weight it takes to compress a spring a certain distance. The higher the spring rate, the stiffer the spring. ...
Since RATE is the amount of rate it takes to compress a spring a certain distance, then yes, the rates would indeed be different. If one side of the truck is heavier it would get a spring that has a higher rate.

The two rear springs on the right -449 and 450. The 449 has more coils and is shorter, the 450 goes on the right and is a tad taller, fewer coils.
If you lower the amount of coils, you'll increase the spring stiffness which is the spring's rate.
The one on the right has fewer coils, so a higher rate - and goes on the right side of the truck.
They are from the same truck..........

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[Sgthooligan]

Has anyone done a weight test on the springs? Like put it into a rate checker, squished it down 1" and see what the load is between the pairs? Then coilbind the soft section of the spring and then test the progressive rate?

I'm thinking that there are "pairs" of springs with different part numbers, but the same spring rate. Because everything is codified, tracked, numbered, etc. Each part needs it's own identifiable part number.

It would make sense that the Rubicon gets special springs for off-road use. Same with Mojave. Sport/Sport S/Willys get general springs. Max tow gets springs for heavy loads. Overland a spring that focuses on road ride. So those combinations would eventually add up, but it's not like each individual spring has a different rate.

The Quadratec page for JT springs list 26 springs. That's 13 pairs to divvy amongst 10 trims and 2 engine choices over 2 model years.

And my spring part #s aren't even listed yet. 68506362AA (L) & 68506363AA (R).

What model gladiator do you have?

 

[MPMB]

What model gladiator do you have?

JTR

 

[Free2roam]

Has anybody measured or have a picture of max tow springs next to Sport S standard tow package set of springs? Was wondering what the difference in height would be.

 

[jc10380]

Old thread I know. How much lift did you get from the 339 and 340 fronts?

 

[ShadowsPapa]

Old thread I know. How much lift did you get from the 339 and 340 fronts?

I got roughly 1" on my Overland.
I then put a winch, steel bumper and skid plate on it and that dropped it 1/2".
I then put 3/4" spacers up front to compensate.
Front rides nice.

 

[basicGlad]

I currently have a Sport S, no tow package manual transmission (1700lb payload) with 443AC and 444AC in the back and I forgot what I have in the front.

Currently measuring
92 -93.5 cm in the front (36.2- 36.8)
96 in the back (37.79)

I have 339 and 340 front rubicon springs. I don't know if I should put them in or if I should buy a 343 and put that in with my 340 instead.

I would like to take a little of the rake out/tiny lift... But I don't want to make body roll worse. Any thoughts?

 

[jc10380]

I got roughly 1" on my Overland.
I then put a winch, steel bumper and skid plate on it and that dropped it 1/2".
I then put 3/4" spacers up front to compensate.
Front rides nice.

Did you also put on the 449 and 450 rears? Basically, I have 1.5" of rake, and Im wondering what kind of rake I will have by putting on the 339-340 and 449-450.

 

[NC_Overland]

I’m looking at a set of Rubicon coils from a JTR LE.

Do I have this correct?
Front (L/R)= 340AC/343AC
Rear (L/R)= 450AB/451AC

TAI

Anyone have a good link to a video doing it at home without a lift? I did mine with a lift and a transmission jack. Way easier it seems.

 

[NachoRuby]

I currently have a Sport S, no tow package manual transmission (1700lb payload) with 443AC and 444AC in the back and I forgot what I have in the front.

Currently measuring
92 -93.5 cm in the front (36.2- 36.8)
96 in the back (37.79)

I have 339 and 340 front rubicon springs. I don't know if I should put them in or if I should buy a 343 and put that in with my 340 instead.

I would like to take a little of the rake out/tiny lift... But I don't want to make body roll worse. Any thoughts?

Teraflex leveling kit. It'll take out the rake, with minimal impact on handling. There's no way to lift and have no impact on handling, but this is minimally invasive. Either that, or I actually have a set of .75" Daystar spacers which I'll give you for free. I have no need for them.

 

[NC_Overland]

2021 JTR
plastic bumper, soft top

Here's my front driver side.
349AB

Couldn't get a clear shot of the passenger side.

349? That’s interesting. Diesel?

The highest I’ve seen up front is 340/343. That’s what mine are and because they’re off of a LE Rubicon.

 

[NC_Overland]

Anyone know what AB vs AC means? I have

340AC/343AC
450AB/451AC

It’s kinda remarkable that they don’t ride rougher. You can feel the road more, but it’s still very forgiving when you hit big bumps or potholes or speed bumps or curbs. I tried hitting everything and nothing was jarring. I noticed that when I sit down on my tailgate now it barely moves when before you’d feel a slight give. I’m right at 200 lbs.

My overland rear springs were so long that mine almost sits even now. The back is just under an inch higher than the front.

 

[Rockabillyroy]

349? That’s interesting. Diesel?

The highest I’ve seen up front is 340/343. That’s what mine are and because they’re off of a LE Rubicon.

Don't think I've seen another post with 349. But no, gas 3.6

 

[NC_Overland]

Don't think I've seen another post with 349. But no, gas 3.6

Maybe they changed the numbers on the ‘21 and we’ve all been posting 2020 take offs.

 

[ShadowsPapa]

Did you also put on the 449 and 450 rears? Basically, I have 1.5" of rake, and Im wondering what kind of rake I will have by putting on the 339-340 and 449-450.

Rubicon springs in the front, max tow springs in the rear. .75" spacers all the way around.
I have the stock rake for sure, looks like 1" higher than a stock Overland all the way around. It would have been heavier in the front but the winch and steel bumper and skid plate dropped it down a bit up front.

My overland rear springs were so long that mine almost sits even now. The back is just under an inch higher than the front.

The Overland springs are long but they compress more with the weight of the truck than the other springs do. The Overland springs were a lot longer than the max tow springs but my truck didn't drop in the rear because of that showing how much the Overland springs compress under a load.

Anyone know what AB vs AC means?

Just a minor revision - could be the amount or placement of the padding on the coils, who knows. I'd be it wouldn't be different rates with that minor revision.

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