Bronco Progressive Coils

Has anyone ran proggresive rate ford coils on their xj? I am thinking about it because I hear a lot of good talk about them. I was thinking about running some of James Duff's 2" or 3 1/2" coils. They are around $115 for a pair, so they are cheaper than a lot of xj stuff. I am trying to figure out how much lift they will give me. I am looking for 5 or 6"'s of lift so I am thinking the 2" coils. I think the bronco guys have too much influence over me, first the d44, 9" and radius arms, then this.

http://www.jamesduff.com/eb/suspension.html

I would think it would ride like a buck board. My superlift softride springs for my pickup were 320 lb/in springs. I'm running 200's in my XJ.

Check the rates.

I emailed them to see what the average rate of the 2" coils are. It's an idea. Couldn't I theoretically cut off a wrap of the bottom high rate part to reduce the rate? My jeep allready rides lack ass with rough country coils. I think I might swap in a set of f-150 coils to get an idea of what it will be like. Whats the rate on a stock '79 f150 coil?

Cutting coils make the rates higher. Besides every progressive coil I've seen has the softer rate at the bottom.

How did you plan on making the upper mount work? My Ford coils didn't have the tight wrap at the end to fit around an XJ shock tower. I don't see how they would sit correctly on the upper end.

James Duff Enterprises said:

The upper wraps are softer for a more comfortable street ride; the middle rates are a bit firmer to handle bumps and dips without jarring; and the last few wraps are a higher rate so that they control the up travel to prevent bottoming out.

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I don't know how cutting a progressive coil would affect it. Just guessing. I don't see why the coils wouldn't work, the top is flat and they are the same diameter as xj coils. Plus I'm not oposed to grafting the upper coil mounts off of my f150 parts truck to the xj.

its start9ing to sound you your the first one to try this, so give it a shot and let us know.

I got a response from james duff in my email.

I would say you should get about 2"-3" of lift. Good luck in your
project, and please let me know if there is anything else that I can
assist you with.

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I told him an xj weighs around 3500 lbs. This seems a little too low. I still can't find an average spring rate for the coils. I am going to see if I can borrow someones coils for a day and see how they work out.