SOA in the back, what for the front?

[Jackrabbit41]

Yes, i know this has been talked about 1000 times everywhere. it is a dead horse, that has been be at and beat and beat. Yes i looked around a lot, but i still am confused. I can't find any exact set ups that answer my questions. So I'm going SOA in the back. I know what to do there, new shocks, spring perches........ but I am confused about the front. I'm not really sure if i know everything thats needed to do front end up to the same height as the back. I know SOA will give me 6inches about, after i take out my old 3 inch lift shackles, but what do i need for the front? I found alexia's kit, but a lot of the parts are no existent on the websites he posted. I know i need springs, shocks, control arm drop bracket or long arms, new track bar, brake lines. Is that it? any recommendations? thanks y'all, and sorry for all the posts. 

[Lee21490]

Yes, i know this has been talked about 1000 times everywhere. it is a dead horse, that has been be at and beat and beat. Yes i looked around a lot, but i still am confused. I can't find any exact set ups that answer my questions. So I'm going SOA in the back. I know what to do there, new shocks, spring perches........ but I am confused about the front. I'm not really sure if i know everything thats needed to do front end up to the same height as the back. I know SOA will give me 6inches about, after i take out my old 3 inch lift shackles, but what do i need for the front? I found alexia's kit, but a lot of the parts are no existent on the websites he posted. I know i need springs, shocks, control arm drop bracket or long arms, new track bar, brake lines. Is that it? any recommendations? thanks y'all, and sorry for all the posts. 

 

The links no longer work in his build thread, All you have to do is google the part numbers though. They just changed the link for the parts is all on their sites.

 

 

I'd just use alexi's as a guide & pick up some WJ control arms to upgrade while you're at it.

[HOrnbrod]

Too many questions. It's much easier to massage the front lift than the rear. So do whatever your going to do in the rear end first with the correct shocks, SOA or whatever. See how it sits, then match it in the front with lift coils, ACOS, whatever. Then correct the pinion / driveline angles with rear wedges if needed, extended driveshaft, adj. track bar, adj. LCAs, etc. If you go SOA you will need all of these parts up front.

[Incommando]

I have a link in my sig. Although long arms or CAD may be the best way to go they are not required for 5.5-6" of lift. I take mine off road regularly. I also drive it around town and several hundreds miles on the freeway at a time with no issues. I use adjustable uppers and bent solid lowers. I went with 5.5" springs but I am probably going to add .5-.75" spacers. The addition of the winch with the steel cable has caused a slight rake to the front. Some folks don't mind a rake like the stock trucks have but I don't like it.

 

So you need 5.5,6, or 6.5" front springs. You will need an adjustable track bar/heavy duty mount combo. You will need extended brake lines. Then you will need your choice of adjustable uppers and custom lowers for your lift height (cheapest), adjustable lowers/uppers. CAD brackets (as far as I know Rocky Road has the only ones that need no mods for the MJ), or long arms.

[Lee21490]

I have a link in my sig. Although long arms or CAD may be the best way to go they are not required for 5.5-6" of lift. I take mine off road regularly. I also drive it around town and several hundreds miles on the freeway at a time with no issues. I use adjustable uppers and bent solid lowers. I went with 5.5" springs but I am probably going to add .5-.75" spacers. The addition of the winch with the steel cable has caused a slight rake to the front. Some folks don't mind a rake like the stock trucks have but I don't like it.

 

So you need 5.5,6, or 6.5" front springs. You will need an adjustable track bar/heavy duty mount combo. You will need extended brake lines. Then you will need your choice of adjustable uppers and custom lowers for your lift height (cheapest), adjustable lowers/uppers. CAD brackets (as far as I know Rocky Road has the only ones that need no mods for the MJ), or long arms.

Rubicon express makes a good drop bracket setup for the mj, Straight bolt on.

[Jackrabbit41]

Thanks all that was really helpful

[Jackrabbit41]

Not putting the price into it, but adj upper and lower control arms are better then drop brackets in every way right?

[Lee21490]

Not putting the price into it, but adj upper and lower control arms are better then drop brackets in every way right?

No

[Jackrabbit41]

What's the advantage of having just drop brackets?

[mnkyboy]

I used to run adjustable arms with drop brackets.

 

[mnkyboy]

What's the advantage of having just drop brackets?

Drop brackets fix your arm geometry which improves ride,flex,and overall performance of your suspension.

 

For a short arm i prefer both,the brackets to flatten the control arm angles and the adj arms for fine tuning,strength,and depending on the arms the flex joints.

[Lee21490]

 

What's the advantage of having just drop brackets?

Drop brackets fix your arm geometry which improves ride,flex,and overall performance of your suspension.

 

For a short arm i prefer both,the brackets to flatten the control arm angles and the adj arms for fine tuning,strength,and depending on the arms the flex joints.

 

 

That's why i recommened the WJ arms.

 

@ 5.5" lift with drop brackets they're pretty much the perfect length, Are WAY stronger than stock MJ arms & Cost under half of adjustable arms.

 

Nice pic btw.

[Pete M]

yup, the closer the arms are to being parallel to the ground, the better the ride. 

[Incommando]

 

 

I have a link in my sig. Although long arms or CAD may be the best way to go they are not required for 5.5-6" of lift. I take mine off road regularly. I also drive it around town and several hundreds miles on the freeway at a time with no issues. I use adjustable uppers and bent solid lowers. I went with 5.5" springs but I am probably going to add .5-.75" spacers. The addition of the winch with the steel cable has caused a slight rake to the front. Some folks don't mind a rake like the stock trucks have but I don't like it.

 

So you need 5.5,6, or 6.5" front springs. You will need an adjustable track bar/heavy duty mount combo. You will need extended brake lines. Then you will need your choice of adjustable uppers and custom lowers for your lift height (cheapest), adjustable lowers/uppers. CAD brackets (as far as I know Rocky Road has the only ones that need no mods for the MJ), or long arms.

Rubicon express makes a good drop bracket setup for the mj, Straight bolt on.

Only if you just use the brackets. The highly recommended reinforcement plates require modification

[Incommando]

yup, the closer the arms are to being parallel to the ground, the better the ride.

Pete have you tried the bent lower arms that make the arms nearly horizontal? They work. If I had any modern technology I would Make and post a video of the ride and handling of my short arms without CAD as I drive around town and hit pot holes or go down the highway at 80 with one finger on the wheel. Although I could have better flex the truck is perfectly capable. If I had an extra grand I probably would have gone with a long arm set-up, though.

[Lee21490]

 

 

I have a link in my sig. Although long arms or CAD may be the best way to go they are not required for 5.5-6" of lift. I take mine off road regularly. I also drive it around town and several hundreds miles on the freeway at a time with no issues. I use adjustable uppers and bent solid lowers. I went with 5.5" springs but I am probably going to add .5-.75" spacers. The addition of the winch with the steel cable has caused a slight rake to the front. Some folks don't mind a rake like the stock trucks have but I don't like it.

 

So you need 5.5,6, or 6.5" front springs. You will need an adjustable track bar/heavy duty mount combo. You will need extended brake lines. Then you will need your choice of adjustable uppers and custom lowers for your lift height (cheapest), adjustable lowers/uppers. CAD brackets (as far as I know Rocky Road has the only ones that need no mods for the MJ), or long arms.

Rubicon express makes a good drop bracket setup for the mj, Straight bolt on.

Only if you just use the brackets. The highly recommended reinforcement plates require modification

 

 

True. Although the reinforcement isnt as needed on the mj, compared to the xj. (Or at least thats what i've been told)

 

 

 

 

yup, the closer the arms are to being parallel to the ground, the better the ride.

Pete have you tried the bent lower arms that make the arms nearly horizontal? They work. If I had any modern technology I would Make and post a video of the ride and handling of my short arms without CAD as I drive around town and hit pot holes or go down the highway at 80 with one finger on the wheel. Although I could have better flex the truck is perfectly capable. If I had an extra grand I probably would have gone with a long arm set-up, though.

 

 

I'm planning on a longarm setup when i swap in a new front axle.

 

Still not sure exactly what route i'll be going.

[Pete M]

 

yup, the closer the arms are to being parallel to the ground, the better the ride.

Pete have you tried the bent lower arms that make the arms nearly horizontal? They work. If I had any modern technology I would Make and post a video of the ride and handling of my short arms without CAD as I drive around town and hit pot holes or go down the highway at 80 with one finger on the wheel. Although I could have better flex the truck is perfectly capable. If I had an extra grand I probably would have gone with a long arm set-up, though.

 

 

 

I should have added that in addition to the LCA angle; the spring rate, tire load rating, tire pressure, bushing shape, shock valving, vehicle weight, and personal preference will all affect the perceived ride quality.  but bent arms won't.  only the straight line between mounting points counts. the arm still has to travel the same arc as it goes up, bent or straight.  the bend is there for clearance and better tire up travel. :thumbsup:

[Incommando]

Not bent like a WJ for tire clearance but like this:

 

Returning the angle to nearly horizontal at the axle end approximates the factory angle without compromising the arc of travel excessively as a shorter straight arm going from mount to mount does. It may be hard to believe that it works especially as "internet experts" lump all short arms, straight and bent, into the same category and most are only repeating what they read on the internet themselves. Again I did not say "as good as" or "better than" the other options just that it does work and is cheaper.

[Incommando]

Not the greatest flex in the world maybe but in IMHO it isn't bad and it actually works on and off road

 

[mnkyboy]

The arms connect two points,the shape of the arm makes no difference. they are bent for clearance.

Run a straight line from bolt to bolt,thats your arm angle.

 

A lot of how a link suspension functions is based on the placement of the instantaneous center which is where the upper and lower arms converge,this is an imaginary leverage point which the suspension works off of,there is more going on but we have been discussing arm angles.

 

A short arms center is behind the rig where it goes but way too high,a long arms center is at the crossmember mid vehicle,this is too far forward and makes for horrible geometry.

 

On a rig with drop brackets the center is typically behind the tire and close to the rigs CG,much like a true 3 or 4 link set up,down fall is the drop effects CG and roll center.

 

A vehicle with drop brackets can apply more power to the ground then a short arm or even a radius long arm rig without unloading issues or control arm jacking.

 

I'm not the best at explaining vehicle dynamics or suspension geomtry but the info is out there if someone wants to do the research.

[Pete M]

Not bent like a WJ for tire clearance but like this:

 

Returning the angle to nearly horizontal at the axle end approximates the factory angle without compromising the arc of travel excessively as a shorter straight arm going from mount to mount does. It may be hard to believe that it works especially as "internet experts" lump all short arms, straight and bent, into the same category and most are only repeating what they read on the internet themselves. Again I did not say "as good as" or "better than" the other options just that it does work and is cheaper.

 

edit: sorry, I mistyped.  I meant for better down travel, not up travel. 

 

that bend exists only to clear that lip on the lower control arm bracket on the axle as the suspension rotates down.  I remember when they were first introduced.  it does not change the control arm angle and does not change ride quality.  If your truck rides nice, excellent! :thumbsup:  but it is not due to that bend.  I have an industrial engineering degree and I promise this is how the physics plays out.

[Pete M]

couldn't find the image I was looking for so i made my own.  apologizes for the crudeness.  I know there are better versions out there and will include a better one if I can find it.

 

red is the lower control arm.  black is the arc of suspension travel.  arrow indicates the immediate direction of travel up once the tire first contacts a positive obstacle (meaning a rock rather than a hole).  Jeep is traveling to the right. 

 

The left image is a stock suspension.  note that the direction of travel is up and then back, effectively absorbing the impact with the spring.  the middle is a lifted suspension.  note the forward direction of travel which jolts the truck up a bit before the spring absorbs the impact.  The image on the right is the same lift but using a bent arm.  note that the arc and direction of travel is exactly the same as the middle image.

[Jackrabbit41]

How do I determine spring perch angle? Or can I just put them on straight up and down and adjust pinion later when I actually swap it in?

I've tried researching it but there no straight forward answers

[Pete M]

http://www.therangerstation.com/tech_library/pinionangles.shtml

[Jackrabbit41]

So i can either shim it or pull the axle out and weld them on them to get correct angle. I would like to have the thing ready when i put it in so i would it be ok to just weld the perches on right even at the top and then just shim the angles i need? any disadvantage to shims?