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Spring geometry (noob question)

XJ Dreamin'

NAXJA Forum User
I hope you'll excuse me if this is too noob :wave: , but...

I've been reading for some time now (threads and web) on all things XJ: OEM, Mod, Street, etc. but on one point I am still a little fuzzy. Namely, extended shackles.

Every discussion of extended shackles includes the warning that shackle extension is limited by the extension changing the pinion angle. I understand that lowering the rear of the leaf pack will change the pinion angle as the pack, the axle, and the pinion rotate around the leaf front anchor, and I understand the need to keep the pinion and output shafts parallel. Now, wedges can bring the pinion back in-line, but isn't it also possible to compensate for the rotation (and add more lift) by lowering the front anchors? Granted that adds fab work to what was basically a wrench job. Also, since the goal is clearance lowering the front anchors might result in more rock rubbing, but wouldn't it be worth it to "lower" the springs evenly, front and back, and avoid using blocks that could increase spring wrap?

Of course, if you do not have the facilities for fab work (which I do not at the moment) then a short shackle/block combo is a decent compromise. But I still have to ask, wouldn't extending the front anchors along with extending the shackles be the better mod (short of a 4-point coil-over)?

Thanks for reading. Sorry for the length,
XJ Dreamin'
'93 XJ 2WD stock, 4.0l HO, AW4, D-35c, LT235/75R15 A/Ts
 
You are absolutely right, it makes for a better mod, however it is more difficult. Lots of guys up here in Canada do it that way, although i have never seen it on an XJ, mostly seen it on Broncos, Scouts and Samurais. One guy in a scout even had shackles on the front and rear of the rear leaf spring and had ladder bars to hold his axle at the right distance. It flexed very well. Even if you lower the front mount though, you would still need to check your angles, and might need a longer driveshaft too. Although i would be remiss if i did not mention that the best thing is just to get a leaf pack that gives you the desired lift. You can also have your existing leaf pack re-arched at a spring shop. My first lift was new Black Diamond front coils and control arms and having my leaf springs re-arched for 3"of lift at a local spring shop. Worked great.
Buck
 
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