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has anyone built their own springs

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I have a pair of rustys 3 inch xj springs , what I was wondering has anyone ever used the main comanche spring and the rest being xj ? Do you think I would be around 3 inch of lift?

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Nope. Absolutely not.


XJ springs sit basically flat in the vehicle. MJ springs (stock) have a couple or three inches of arch at unladen curb weight. Match up a Comanche main leaf with the other leaves out of an XJ and you'll have the other three leaves pulling the main leaf DOWN. You won't even get normal MJ curb height. With Rusty's crap 3" "lift" springs ... you might get stock height.


For reference -- Rancho sells the same add-a-leaf for the XJ and the MJ. Look in the Rancho catalog and it says this same AAL provides 2" to 2-1/2" of lift in an XJ or an MJ.


That's impossible, of course, since one is SOA and the other is SUA. So I called Rancho and talked to one of their suspension engineers ... who talked to another suspension engineer ... who brought in a third suspension engineer. In the end, they said the catalog is wrong, it provides about 1" to 1-1/2" in the MJ and 2" to 2-1/2" in the XJ.


Sou you're looking at taking springs that will lift an XJ a half inch more than this AAL, and using the parts with a STOCK MJ main leaf. I don't think this is a great combination.

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i have mixed and matched springs for years on toyotas



but it takes a lot of trial and arror to get it right

That's the problem. I made the rear springs for my championship autocross car that way, but I wore out a lot of hacksaw blades.


Are those 3" XJ springs out of the vehicle? If so, what's the arch on them? I think Rancho's catalog is available on-line, and IIRC in the back of the catalog (or maybe in the catalog itself) they list specs for replacement (stock) springs. I'd be interested in comparing the free (unloaded) arch of a stock MJ spring with the arch of those 3" Rusty's XJ springs. I'll bet they're actually pretty close.

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