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Thread: Quadratec replacement leafs: standard or medium duty? Reply to Thread
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  Topic Review (Newest First)
04-12-2015 09:25 AM
Rob K I have a four door 1995 4x4 with 2.5L engine and AX5 transmission. I put in Crown heavy duty springs on mine and gained 1.5" over stock. I've hauled quite heavy loads several times, but not regularly. The ride is very stiff and it has not settled in years. The shackle angle is near vertical. In hind sight I should have gone with the medium duty. At this point I can remove a leaf or install relocation brackets. Raising the front will help also since it has a fair amount of rake at this point. It's not bothersome enough for me to change it at this point. Have been driving it as is. I would agree, medium duty for the OP.

Don't expect things to work out perfectly on the first try when replacing suspension. All you can do is start by putting in new springs and adjust from there. Shackle relocation brackets will allow you to make some of the necessary adjustments. Wish I would have known about these brackets when I installed my springs. The adjustment would have been quite helpful. You can always install them after you try the new springs out.
04-11-2015 12:14 AM
Charley3 Well, it's my opinion (France) that you've been overloading your XJ. It's clear that we aren't going to agree on that, so we'll have to agree to disagree.
04-07-2015 12:49 PM
XJFrance I think this is getting into the weeds of leaf springs. The HDs have a load rating of 755lbs, but I dont think that is the same as the MAX load they can handle. The road rating, in my understanding, is the amount it can hold at a certain height.

I loaded the back of the XJ until it was 18" center to fender. Starting at about 19.5", that would mean the truck sagged down 2.5", and still had plenty of arch. So, the take away is that these babies are STIFF. After adding the helper leaf, I could bounce up and down on the hitch and it would barely move, and I am over 200#. These are not springs for someone that doesnt want feedback from the roads.

When I bought and installed them, I was excited because I wanted a little lift, and initially got it. That didnt last, which is why I caution others from viewing them from that perspective.
04-07-2015 11:29 AM
jeepguy03 Yeah I think the medium duty springs will work best. Q-tec offers the medium in both a 605 and 405 spring rate but don't list a spring rate for the standard duty. Heavy duty is listed as 755. Hmmm.
04-07-2015 11:22 AM
Charley3 Based on my own experiences, I do think there is some height difference even after settling, if they haven't been overloaded, and especially if they've never been fully loaded.

Most people won't overload them. Many people will never even load them to capacity. For those people there will be some height difference.

However, for the heavy loads you've carried, I can believe the height difference can diminish with settling.

However, a standard spring would settle more than a heavy duty spring, if both were subjected to the same heavy loads that you've carried.

The important point we both agree on is that it's best to choose the spring according to the loads a person intends to carry, and we both agree that's a medium duty spring for the OP. So we agree on the important points.
04-07-2015 11:11 AM
Charley3 My 96 XJ came with OEM standard duty springs. My 99 XJ came with OEM tow package (medium duty) springs. I bought both XJs with 33K miles on them.

With OEM standard duty springs, 30 x 9.5 tires rubbed slightly on the flares, but only occasionally and not enough to harm anything.

The OEM medium duty springs sat about 1/2" higher and could clear 30" tires with no rubbing at all.

So in my personal experience, there is a little bit of ride height difference between those two. I've already heard the OEM heavy duty (up country) springs ride about 1" higher than standard duty.

However, you're reporting less differences in ride height than I am, and the other fellow reported more difference than I did. So I'm not entirely sure what to make of that. However, I will note that I'm referring to my experiences with OEM springs, and I think he was too. I think you're referring to Crown springs. I'm not sure if the brand makes any difference. I've purchased Crown and OEM bushings and they were equally good. I've purchased Crown and OEM suspension snubbers and the Crown were significantly better.

So I don't know. It might all have to do with how much weight the springs have been subjected to. It sounds to me like you may have overloaded your springs, especially the heavy duty ones. An XJ is a 1/4 ton truck. So that's a 500 lbs payload capacity in rear cargo area, if I understand correctly. You said you put 1000 lbs back there. So it sounds to me like you significantly overloaded your heavy duty springs. I wonder if that might have caused them to lose their extra height?

P.S. - Aren't the heavy duty rear springs rated to haul 750 lbs? If so, you still overloaded them at 1000 lbs, IMO. Perhaps that caused them to lose some height?
04-07-2015 10:01 AM
Originally Posted by Charley3 View Post

France, did u read the other guy's post confirming different ride height? Though I'm not sure it's as much different as he said.
I did, which is why I acknowledge that there will be an initial increase in ride height. I am not sure how long after installation of the HD leaf packs people have measured to see how they settle and how much. My caution comes from my real world experience that if you load them down all the way, they are not going to come back up to the +1-2" rise we all initially experienced. So that leads me to believe they will eventually settle there at some point, al biet slower than a softer spring. So my comment was more to say, choose these shocks based on what you are going to haul or what your preference in how it rides over anything you will net in "lift".
04-07-2015 05:01 AM
peelman When I replaced my leafs on my 2k xj, I opened the old set I replaced and stuck one of the used leafs in the new pack. That raised the rear an inch or two which I need for my tool box and small trailer.
04-07-2015 12:43 AM
Charley3 I wonder if Crown brand settle more than OEM? I wonder how Dorman compares?

Rocky Road Outfitters sells OEM for very reasonable prices.
04-07-2015 12:41 AM
Charley3 We agree that load capacity is the most important issue when comparing these springs, and we agree that the Medium Duty would probably be best for OP.
04-07-2015 12:37 AM
Charley3 Re Heavy Duty (like Up Country) rear springs vs Standard Duty rear springs...

France, did u read the other guy's post confirming different ride height? Though I'm not sure it's as much different as he said.

He's saying ride height is 1.75" different. You're saying it's not different. I'm saying I think it's about 1" different. Perhaps some of it depends on how much cargo weight.
04-06-2015 08:27 AM
Originally Posted by Charley3 View Post
Ha! I knew those HD ones sat higher than Std duty ones.
I think this statement is misleading, and largely depends on how they will be used and how long after installation.

I installed the Crown HD leaf-pack in a 01, and immediately measured ~18.25" (+1.25 over stock), but less than a month later after once hauling a trailer and once moving about 1,000 lbs of tools in the rear, I was down to ~17.25 (+0.25"), which can basically be considered stock height.

Now after adding a helper spring, I am almost right at 19" (+2.0"). So, depending on your use, actual height change can vary pretty dramatically. If you install stock height (STD) duty leafs, and measure 17" after right after installation, there is a good chance over time (depending on how they are used) that they will settle out to below stock height; which is likely what happened to the leafs in the first place.

So, I would suggest not looking at this from a "How much lift will I net" point of view, since the idea of the spring rate really isn't the same as a "lift-kit", but to view it by how much cargo you can carry and how stiff you like your ride. The OP doesn't seem to have a need for HD springs, so I would suggest the Medium Duty, which will maintain actual stock height longer and remain daily driver friendly.
04-06-2015 12:25 AM
Charley3 Ha! I knew those HD ones sat higher than Std duty ones.
04-05-2015 09:04 PM
JrTjK I've run them on 3 of my XJ's. If you want to go 1 3/4" above where it sat new factory, get the 4886186AA. If you want regular replacement size with no lift, order the 4886185AA part numbers.

Paired with a good shock, they work dandy. The 4886186 go nicely with a 1 3/4" front spacer or new 2" lift springs.
04-04-2015 12:59 PM
Originally Posted by pismo61 View Post
I have the Crown HD springs and sensatrac shocks(with upper rear shock extentions).They dont seem stiff to me.Most of my vehicles have been Wranglers and small pickups.So I maybe used to a stiffer sprung vehicle.Dunno?With the crown HD springs and JKS shackles I sit at 20 inches(from center of wheel to fender flare),total 3 inches.They have been on for 3 months.PS I added 3* shim also that about a 1/4 of an inch.
Maybe it's the RC shocks, which are on the replace list when I can justify the expense. But it was stiff as hell after I first put on the HD springs before I lifted. I would not do that lift brand again given the chance. I grew up in suv's and trucks and have only owned cherokees myself.
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