[ashmanjeepXJ]

It seems to me that all it does is let the axle drop without adding any down pressure (like a revolver shackle)

No,

you can do a 3/4, where the top 1/4 elip has compression and does not sit flat againse the frame. In this configuration you could make your upper 1/4elip the equal rate to your lower 1/2 elip leaf and would increase your up and down travel while maintining the same "down pressure" as just the 1/2elip.

axle warp is a problem, and the this setup will have more trouble locating the axle so you may also need a panard bar and tracktion bar...

The longer the upper 1/4elip is the more you will need a panard bar.
The softer you make the top 1/4 elip the more axle warp you will have and need a traction bar.

So if you make the top 1/4 elip really stiff you have less problems with axle warp, will not "need" a traction bar, but will have minimal flex advantages, but may give desired height, almost like jsut a shackle lift.

If your 1/4 elip is short you will have less problems with axle location and will not "need" a panard bar, but will have less added wheel travel.

If your 1/2 elip leaf is 150lb/in thats only 75lbs/in on each eye of the leaf, so for a matched 1/4 elip rate with some up travel youd want about a 75lb/in 1/4 elip... correct?

So how long of a top 1/4 elip can be used with out really needing a panard bar. I was thinking of using about a 25in 1/4 elip off a F350, either only the top leaf or top two leafs (stiff) to minimixe axle warp. The 1/2 elip is about 25in from the shackle to the axle center so the frame end of the top 1/4 elip will mount directly above the axle center! is that too long to have any axle location...

Any non noobs with some trial and error experience have input....

 

[ashmanjeepXJ]

Ashman, I've seen you on the Nissan boards, haven't I? BTW, I run www.Nissan4wheelers.com

Yea, MCsoo or "MCfly" i think mikes name on that board. hangs out there, I check up every now and then.

F350s leafs like mine, 70s years, are 2.5in wide same as my lower pack.

They are thick leafs and have many in the pack. I plan to use jsut the main leaf and maby the second if I need to stiffen it up.. not flexy like the nissan main leafs but would be more stable....

Worst case you build arms to fix the 3/4 elip warp and wandering problems then later $$$ converter to coil overs....


some F350 leafs...

 

[ashmanjeepXJ]

Good to know on the F250 leaves. Will do a little more digging on the feasibility. Will need longer brake lines and I'm a little concerned about my driveline length (embarrasing to pull out a slip yoke!)

Well the axle will move twards the transfercase on drop, so will push teh drive shaftinto your slip yoke on drop and wont fall out, it can only bind on drop...