XJ - Need MJ Leaf Spring Advice

[Yoda]

Got what I think is an interesting question.

I just picked up a 2000 XJ in great shape but the leaf springs are shot. It is in stock form but I want to make it sit like an Up-Country which is 1-1.5" above stock height. Plenty of room for 30" tires. For the next couple years it will be a daily driven commuter Jeep, family hauler and camping rig. Down the road I will probably lift it to 5" and build it up for more hardcore off-road use. I have an idea...

Get some OEM replacement MJ springs. They are about 5.5" longer. I'd get Iron Rock 4x4's leaf mount relocation kit and move the front spring mount forward about 3" and move the rear mount back about 2" using an adjustable shackle relocation kit and boomerang shackle. This will roughly get the tire centered back in the wheel well. I'd convert the XJ rear to Spring Under Axle (SUA), essentially the same as the factory MJ.

I've read that the MJ rear sits about 1.5" higher than the XJ. So if I set it up just like an MJ (SUA), the lift height will be perfect. Then when I decide to lift it all I have to do is go back to spring over axle (SOA) and I'm at about 5.5" or so of lift. Just need new shocks at that point.

My Assumption (need help)
1. Longer MJ springs will ride and flex better than shorter springs with a similar spring rate.
2. Longer MJ springs have more arch and will have more suspension travel.

If my assumption is wrong...then there isn't much point. Just get XJ OEM springs. If I'm right, I'll see an immediate improvement and when its time to lift I just have to flip the axle to SOA.

Thoughts?

 

[Blackjack]

Depending on which MJ spring you have they could be anywhere from 1200-1700 lbs although they are two stage. The XJ springs are 650-750 lb single stage. You can get the 97-547 spring which is the high arch for under $400 for the pair and save the cost and work of fitting the MJ springs.

 

[97TJNM]

I'm not sure how your plan will work out, but it sounds like you're doing your homework. If you go that route, good luck and I hope it comes out exactly like youu want it!

Just an FYI, my 99 XJ's rear springs were really tired when I got it, and I wanted to run 31's. I replaced them with factory HD springs (they came on XJ's with the factory towing package) and added straight shackles on the rear of the springs. This added about 1" in the rear. In the front, I put 3/4 spacers.

It has a very slight forward rake, and I get a very minor tire rub at full steering wheel turn to the passenger side, but otherwise, no interference. Of course, this is my grocery getter, so it doesn't see much worse than the occasional forest road, so take that for what it's worth. If I was doing it over again, I'd put either 1 or 1.25 inch spacers in the front to level out the rake and hopefully do away with the tire rub at full right turn.

That said, it was a really cheap way to get the XJ running 31's.

Just my experience.