I have a 96 XJ Sport. The previous owner used it to haul stuff to hunting shows so every weekend the rear end was packed down. The leaf springs need to be replaced something bad. My question is when I look at the options online I am given the option if light duty, medium duty, or heavy duty. Which is the standard and what is the difference between the 3 choices? Is there any change between the ride height and the feel in the suspension going down the road?

 

Light Duty: Not towing or hauling anything you won't want light duty if you plan on packing it down with extra stuff you might need on the trail or what not.

Medium Duty: A little bit of towing like bikes and crap maybe a dirt bike or something maybe some aftermarket bumpers and crap like that

Heavy Duty: Planning on packing the Jeep with bricks or axles or something super heavy, I would think if you work in construction and haul really heavy crap you'd want heavy duty.

(All this is just based of my common sense anyone feel free to chime in.)

Mediums duty is probably fine for an xj after all an XJ isn't a towing monster.

There shouldn't be any differences in ride height idk about feel on the road though.

 

Weight carrying capacity and ride height.

Dorman 929-301 and Crown HD's are the most popular "stock" replacements.

If you start searching and see people saying this spring gave me 3" lift keep in mind they're usually measuring against their old saggy springs.

I put Dormans on my 01 XJ and it went from 16.5" to 18" (center of wheel cap to bottom of trim). I believe the Crown HD's would give you another inch, almost like the UpCountry package.

 

OEs came with various spring rates and load ratings depending on the options, as normal duty or heavy duty.

SDA = Normal Duty
SDB = Heavy Duty

Chart for front coil springs

http://lh6.ggpht.com/_VzIUbRjlFkU/TS...ing_chart.jpeg


Spring Rates from the chart is actually a Load Rating.

The load rating is the # lbs of weight a spring is designed to carry when deflected to a certain height.

A spring rate is lbs per inch (lbs/inch) for every # lbs applied the spring will compress one inch.

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A light duty spring is softer and provides a softer ride, under lighter payloads.

Differences in choices would be dependant on the dry weight , payloads and the type of use.

Dry weight = vehicles base weight plus any add-ons, such as hd bumpers, winch, tire carrier, etc. minus the payload.

Spring ride height is dependant on the spring rate & load rating. The more you compress a spring the stiffer it becomes. Generally a HD spring will have a harsher ride than a light & medium duty spring. Heavier payloads, when using heavy duty springs a vehicle will handle better and have a better ride. Ride quality and handling is also dependant on your shocks, and how they're matched to the springs.

If you want a good ride under normal conditions and also be able to carry a constant heavier payload.

Look around for dual rated rear leaf springs.

These use a flat 5th overload spring 4 + 1. There is spring rate for four (4) leaves and then another spring rate for 4+1, five leaves.

The 4+1 spring is sometimes rated as either medium or heavy duty, depending on the spring rates.

You can also add a 6th spring ... for a 5+1 dual spring rate.

OE part numbers

14 SPRING, Rear Leaf
52000 050AB 1 [ZFS,ZUS], Right or Left
52000 051AB 1 [ZFT,ZUT], Right or Left
52000 707AB 1 [ZGU,ZVU], Right or Left
52000 706AB 1 [ZFU,ZUU], Right or Left
52000 544AB 1 [ZGS,AVS], Right or Left
52000 545AB 1 [ZGT,ZVT], Right or Left
52002 390AB 1 [ZGV,ZVV], Right or Left
52002 392AB 1 [ZGW,ZVW], Right or Left

Aftermarket rear spring rates

http://www.jeepforum.com/forum/f11/s...-rates-613756/

 

Thanks for the replies.

I am thinking about leaning towards the medium duty. I dont town anything except for the occiasonal small utitly trailer. I dont carry much in the way of gear except when I go to OBX in which I have a cooler and some friends in the XJ.
I dont do much wheeling off road except for at OBX or around the family farm.
Based off that info I think medium duty is good unless anyone thinks that is overkill and I should go with light duty?

 

My suggestion would be to buy springs/leafs that are equal to the factory UP Country Package. A med duty spring with about 1 1/2" of lift over the std. stock spring/coil package.

That would fill your needs very well and give you a little bit of lift for off road use, not a lot just a bit.

 

For what it's worth, factory ride height in the rear in that dimensions is 17.5". So half inch of lift, officially. In practice you probably noticed your U joints aren't in great shape anymore lol

 

I use a pair of OME rear springs installed from an OME lift kit. These are medium duty and work perfectly well for all around use, on road, for towing and heavier payloads.

The primary spring pack (4 leaves), spring rate is 137 lbs/inch approx the same as the OE springs ... the fifth overload spring rate is 257 lbs/inch and isn't functional until after a heavier payload is added to the rear of the Jeep.

If you need to go off-road at all, I would recommend at a min. ~2 inch lift ... it makes a difference with exhaust repairs, muffler replacement and other damage that occurs to underside from rocks, holes, etc.

OME use right and left springs for their suspensions so their will be two part numbers

CS035RA & CS035RB (rear 4+1 springs Jeep Cherokee XJ)

http://store.arbusa.com/Old-Man-Emu-...RA-P20966.aspx

http://i845.photobucket.com/albums/a...1_136_5604.jpg

http://i845.photobucket.com/albums/a..._1_64_3796.jpg

http://i845.photobucket.com/albums/a..._3_79_2872.jpg