Razmo

Per Quadratec on behalf of Crown. They tell me they have no specifications on the Standard Duty Spring. Wonderful! Also, they tell me the second one listed is also a Medium Duty spring, which look to be inline with General Springs. At this point, I'm thinking either MD the way to go..

These are the specs we have listed...
56010 10 07 1 LEAF SPRING ASSEMBLY 84-01 XJ MED DUTY 4886187AA 92.99 4 LEAF, ARCH OF SPRING IS 5 1/2" - 485 LOAD/135 RATE load rating LK

56010 0016 07 1 LEAF SPRING ASSEMBLY 84-01 CHEROKEE XJ 52000707 97.99 ARCH OF SPRING IS 5 7/8", 605 LOAD/135 RATE LOAD RATE LM

56010 11 07 1 LEAF SPRING ASSEMBLY 84-01 XJ HD 4886186AA 92.99 7" Free Arch. 755 Load Rating

EZEARL

"Earl, so are you guessing Crown lists 52000706 as HD even though it was SD as an OEM?"

That is my understanding. BUT as an OEM std spring it has the most load capacity of the other std spring offerings. So the Crown spring even though listed as HD doesn't have near the load capacity as Crown spring that duplicates the Up Country factory offering(#52002392). In other words OEM spring 52000706 is the last of the std springs before getting into OEM 52002392 the hd spring.

Thought I'd lost this:

XJ Leaf Spring Specifications

Springs, rear
LL - 3-1/8" free arch, load rating 405
LM - 5-5/8" free arch, load rating 605
LS - 6" free arch, load rating 675
LT - 7" free arch, load rating 755 UpCountry + 1 "

Dealer part numbers:
52000050 Standard Duty, Coded LB
52000051 Standard Duty, Coded LC, EC
52000706 Standard Duty, Coded LN, ES
52000544 Heavy Duty, Coded LK
52000545 Heavy Duty, Coded LL, EL
52000707 Heavy Duty, Coded LM
52002390 Heavy Duty, Coded LS
52002392 Heavy Duty, Coded LT ( UpCountry package +1" leaf spring)

Crown catalog part numbers:
84/01 Standard Duty (LL ) 4 leaf - Jeep P/N 52000051
84/01 Heavy Duty (LS, ZGV, ZVV) 4 leaf -Jeep P/N 4886185
84/01 Heavy Duty (LT, ZGW, ZVW) 4 leaf -Jeep P/N 4886186 or 52002392 - UpCountry + 1"
84/01 Heavy Duty (LK ) 4 leaf - Jeep P/N 4886187
84/01 Heavy Duty (LN, ZUU, ZFU) 4 leaf - Jeep P/N 52000706
84/01 Heavy Duty (LM, ZGU, ZVU) 4 leaf - Jeep P/N 52000707

Tbone289

^That's good stuff!

Razmo

Earl, this is a ton of help! You da man.. I'm thinking Crown HD 52000707 the way go here given it's free arch of 5-5/8" and 605 load capacity. However, the Crown HD 4886185 is tempting as well given it's 6" of free arch and 675 load capacity. Wouldn't you think either of these would ride around standard ride height?

Were you also about 1" over standard ride height. same as Tbone? I'm wondering if Tbone is sitting on 7" free arch HD's as well?

All in all, in either case. I should likely run HD Shocks front and rear as well, right?

Thanks,
Raz

Freerider15

I have to laugh at many of the responses here, talking out their *****.

Who here has actually run air shocks?

I've known several, and they do exactly as their designed.

If you tow occasionally, they work just fine.

Not much different than airbags on a tow rig to help level things out.

Several have used them to help re-arch old oem (or mild lift) leafs.

HD leafs are all fine and dandy, but they ride like bricks when you're not weighted down. Many of the HD springs also provide lift, which some don't want.

The OEM mounts, the OEM crossmember, etc. are all capable of handling any extra load.

Tbone289

Earl and I are both on the 7" free arch HDs, and both sitting 1" over stock.



I'm not sure what HD OEM replacement springs you've run, but I can tell you mine don't ride like bricks unloaded. They still flex well unloaded off-road as well. They're stiffer than standard-load springs, of course, but I've experienced a much worse ride in factory HD pickups. OEM standard-duty leaf springs are pretty weak.

I think we've covered your point of extra lift.

Applying extra load to shock mounts that are not designed for it isn't really a good idea, and just because people get away with it still doesn't make it a good idea. Adding airbags between the uniframe and axle housing isn't really the same thing, and is a much better idea.

Freerider15

I've run the Dormans, and have known other running other various brands. If it's a near stocker, then the ride will definitely suffer. Maybe not quite like a truck (I own a leaf sprung F-350, so I'm well aware in that regards), but it will be noticable.

"Applying extra load to shock mounts that are not designed for it isn't really a good idea"

The XJ has a pretty decent tow rating, and if you think the OEM mounts aren't up to it, well their design and consistent use in towing prove otherwise (as well as abuse offroad).

I could draw it all up in an FMEA program, do fancy numbers and show that it's well within spec...but meh.

"Adding airbags between the uniframe and axle housing isn't really the same thing"

No, not the exact same thing, but still not too far off.

Air shocks aren't meant to SUPPORT the entirety of the weight, much as airbags aren't. They're simply used to help level out the rear, to help in towing applications.

You can try and snub your nose at them all you want, and you don't have to use them. That doesn't mean they aren't perfectly safe, well within the engineered failure of the mounts, and haven't been used extensively by vehicles of all types for decades.

TwistedWrench

Not to start a pissing contest here... But seriously?

Just because a product exists, doesn't mean it's safe, reliable, or a good idea. Case in point, "twist in" coil spring spacers. Air shocks fall in the same box.

Has every air shock wearing ride I've worked on needed repairs to it's upper shock crossmember?

No. Not yet at least.

Has EVERY vehicle Ive had to repair said crossmember on been equipped with airshocks?

Yes. Every. Last. One.

Airbags and airshocks are NOT "close" to the same thing at all. In any way. Whatsoever. Airbags Help support extra load by spreading the load to the framerails, by design the strongest part of the structure. They also do not replace the existing shock absorbers, and so do not eliminate the parts that help dampen and control the bound/rebound of your suspension. Which is of notable importance, especially when hauling extra load in a short wheelbase SUV.

Now im sure youll come up with a clever response to this.

But you're wrong.

Sorry.

Freerider15

Yeah, ok there buddy

You keep doing you, I'll keep doing me, since you can't seem to comprehend what I'm saying and want to stand on your soapbox.

The rest of us will keep using air shocks responsibly as we have for years, without issue.

Tbone289

I think the lack of comprehension here is your issue. Shock mounts are not designed to carry any weight of any vehicle, period. Tow rating has zero bearing on whether shock mounts are up to the task, since they are not weight bearing. Air bags are mounted to weight-bearing frame and suspension members, so it is not the same.

Twistedwrench has first hand experience of crossmember damage from air shocks, and yet using them is no issue...and we're the ones "talking out of our *****".

So, since you can run all the numbers... Please, tell us exactly what amount of force/weight the rear shock mounts of an XJ are designed to carry.

Freerider15

I have no problem with the comprehension.

He said:

"Has every air shock wearing ride I've worked on needed repairs to it's upper shock crossmember?

No. Not yet at least.

Has EVERY vehicle Ive had to repair said crossmember on been equipped with airshocks?

Yes. Every. Last. One."

His own post shows correlation is NOT causation. Things can be used incorrectly my anyone. Just like any towing additive, they should be used responsibly. As long as the tongue weight is within reason, it's far safer to tow level, than with sag, would you not disagree?

And yes, I trust my real world experience, as well as those I know who work for large automotive companies designing things like this (I'm a Mech. Eng. myself, not the first time around the block).

Should airshocks be used to justify towing a 10k load? No.

Are they just fine for leveling out the rear when towing a small camper or utility trailer with ATV's/SXS's? Yep.

Air shocks are popular with quite a few overlanding types. Hint: you don't keep them aired up the entire time...hence why they're adjustable.

You don't go wheeling with them aired out...you adjust them as needed.

It's like people defending that a lack of steering stabilizers does in FACT contribute to death wobble

As I said, you can keep going on about something you prefer not to use, when you may have never used them.

The rest of us, will keep on our merry ways.

Tbone289

It's actually not like that at all. Your comparisons (this one and the airbag one) are completely lacking in logic.

Since you admit that the shock mounts have limitations in their weight carrying capacity, can you tell us exactly what that capacity is, or should we stick to appropriately recommending that people upgrade weight-bearing suspension members when they require extra weight-carrying capacity? I'm not going to recommend that someone use airshocks to help support the weight of a trailer with a 300-lb or higher tongue rating when I have no idea what weight a shock mount will support, since it is not designed as a weight-bearing suspension member, and thus has no published weight bearing capacity.

So, you state that the 300lbs that the OP stated is safe. Let's say we just take your word for that. Since you seem to know the exact limits of their design, what is unsafe? Also, since the OP has sagging springs, if he mounted air shocks to level out his XJ, what force is he applying to level out the truck before he even applies the tow weight, exactly?

Freerider15

Not really.

All depends on load, and fatigue strength of the working materials with the dynamics of said load.

A light duty truck (such as my F-350), has a far greater tongue weight load capacity than an XJ.

Sheet metal is still sheet metal, and the cyclical loading and unloading with the F-350 would cause issues much quicker than later.

As so, the support from the rear needs to be tied to two areas that can withstand said load. On a light duty truck, this needs to be the frame, and somewhere on the axle. Since a bed is not permanently affixed to the frame, flex can and does happen, which would have negative effects on the actions of the bag. As well, the flexing, coupled with the extra support load, would cause fatigue issues in the bed.

Now, and XJ is a full (though still sheetmetal) body. However, it's tongue load capabilities are nowhere near that of a light duty truck (in reality). As such, the flex seen between the bed, and the axle is negligible in comparison as it is all once solid structure. The spring rates of an XJ as also minute in comparison to a light duty truck. Airbags have been used on XJ's in the past (and IIRC there was even an OEM type option at one point), for "heavy" hauling. So, couple these items, with the fact that the require added pressure to an airshock to level out the rear, is minute in comparison the the overall load added to the mounts.

The tongue weight maximum load for an XJ is 500 lbs. The max tow rating is 5k lbs, thus a 10% ratio (within the 10-15% maximum).

Unless you're overloading the rig (I'd never tow much more than maybe 3k with an XJ), being well under the 500lb. mark isn't hard.

In reality, I've seen (and have done myself) things with XJ's that (slamming the rear down, airing them out 6' feet of the ground, etc.) with stock mounts that if there was ever any concern, I would have had it there. All of them survived, crossmember and lower OEM mounts. Their shocks...well not all of those survived.

Freerider15

Gotta stop editing your posts for me

When I meant re-springing, I did NOT mean while towing. The several that I have known that have done it, did it for a few days to revive old springs. One of them is still going on those springs.

If you have sagging OEM springs, yes the best option (if you have the budget), is to buy new OEM springs. Many don't want the added lift, and harsher ride from HD springs (I have a set in my wife's '96XJ).

I answered a few of those with my last post.

Properly loaded, I can get my F-350 with an 18' trailer, with buggy and assorted spares/tool/etc. a tongue weight of a bit under 1k lbs. (~1250lb. max) when the load weighs upwards or 10k lbs. Getting an XJ towing load well under 500 lbs. isn't that hard (done it several times myself). Anyone who tows remotely regularly should have a tongue weight checker.

So, loading an XJ properly shouldn't be that hard. Most pop ups, adventure trailers, etc. can be moved around with their mounts by hand. Would I advise towing a car with an XJ? Fawk no. I had to tow a 8x12 trailer a few hundred miles up and over several passes in CO in my old '91. That was beyond what I care to do ever again.

Now, yes this does not take into account a fully loaded back area of an XJ. That being said, it's all about being within your limits and being responsible.

Tbone289

Sorry about that, sometimes I hit post before I'm really done with my thoughts.

So, basically what you're saying is that you've used them and they have worked for you, but you have no idea what the limitations are. Great. I will keep "talking out of my ****" about air shocks because I don't know what the limitations are, and thus I don't feel like I can safely recommend them, and I will recommend a better approach, IMO.

The XJ's tongue weight maximum load is 500lb only with a weight-distributing hitch, 200lb without one. How does a 300lb weight of a moto carrier (what the OP is using, not a trailer) on the hitch apply to that rating? I would assume that it would apply to the 200lb rating since it's dead weight and he would actually be over the rating of the hitch.

I regularly tow a 2700# RV (unloaded weight) with WD hitch and electric brakes with no problem, but that's different than his case due to the weight distribution.