drive shaft questions?

[jd4242]

Does anyone know how much a stock drive shaft will compress under max rear end compression?i just had mine out extended 3" and think i should have gone 2".when i took my measurements i got 47 but i just took them again before installing the new shaft and got 46.the tape must have been at the end of the ujoint not center!!;(it fits fine but looks like it only gota about an 1.5-2 of compression.hard to measure by myself.so im wondering if that's enough or will my rear make it compress more than that.i have soa with a AAL in the rear so the compression and extension should be close to stock but just driveshaft length should be different.i don't rock climb or do any high speed offroading just beach and some mud trails.i may add shackles and f150 seats later to help but don't really want to go any higher!! any help will be appreciative

 

[4x4junkie]

There's a ton of variables that'll change how much your driveshaft's slip-spline travels (dynamics being one of them).

Probably the easiest way (though still not real easy) to get some idea of it's travel is to put enough weight in the back to load it down to (or near) the bumpstops (bunch of bags of cement maybe), then allow another 1" or so spline travel for windup of the leafsprings.

I would say with 1.5" of travel, chances are you probably are OK (the axle tends to move backwards slightly as the leaves flatten out during compression), though if you're concerned about it, then it's certainly a good idea to check (it bottoming out and binding of course would wreak havoc on all sorts of stuff).