Topic: Why the 1" drop in front spring hangers?

[TheBandit]

I'm curious what the idea is behind the 1" drop in aftermarket front spring hangers. Is this primarily for castor, pinion angle, additional lift, steering clearance, or what?

I'm thinking about fabricating my front SAS spring mounts into the front crossmember so that the spring bolt goes just under the stock crossmember. I'm guessing it would have a similar vertical location or sliight rise over a stock SA Toyota. What pitfalls should I be aware of?

I would be using an aftermarket spring like a Marlin 4".

This is kinda what I'd like to do:

[Duffil]

From what I've noticed, caster and pinion angle.  Without that drop, if you lengthen the shackles, you'll have to use caster wedges.

[Hottrod81]

I had to use 3 degree caster wedges with the 1" drop hanger.  My long spline driveline was binding due to the angle.

[Duffil]

  I am on stock hangers, I have to run shims for caster, but I don't bind.

[TheBandit [OP]]

From trig, a 1" drop at the front of a 47" long spring should rotate the axle about 1.2 degrees.

Is this a significant differrence? I am curious about the tradeoff between pinion agle and caster. Is 1.2 degrees a problem for pinion angle if you are running dual cases with a longer front d-shaft? It seems like the added caster of a no-drop hanger would be a good thing.

[Hottrod81]

At full droop on my front end, I bind in the front without caster shims.  I run 4" Marlin springs, but also have a 1" drivetrain lift.  I think it matters on what kind of springs you have also because the spring bolts are in different locations.

[Duffil]

From trig, a 1" drop at the front of a 47" long spring should rotate the axle about 1.2 degrees.

Is this a significant differrence? I am curious about the tradeoff between pinion agle and caster. Is 1.2 degrees a problem for pinion angle if you are running dual cases with a longer front d-shaft? It seems like the added caster of a no-drop hanger would be a good thing.

1.2* of additional caster is not good.  If you give the axle negative caster(towards the ground) the truck will steer under itself.  If you give it more the other way, it will be slightly more stable at higher speeds, but harder to turn, and you end up with more camber under a turn.

Of course, if you were trail-only, I doubt you would notice anything.

[snowshoebrue]

the drop hanger also helps you clear your pitman arm if you have highsteer. 

[MiniSimp]

Even if you have a flat pitman arm, it will still rub without a drop hanger.
(someone said something about bumpstops? I can't remember.... )

You can see in this picture that I rub on the spring, and it broke off my zerk fitting. I see a Marlin 1" drop hanger in my future, I just have to figure out how to lower the suspension 1"

[TheBandit [OP]]

Thanks for the helpful info everyone. Sounds like there are a few good reasons for doing the drop hanger.