wheelerboy12
Full Access Member
- Joined
- Aug 13, 2012
- Posts
- 209
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- 5
- Location
- Dundee, OR
- First Name
- jeremy
- Truck Year
- 1978
- Truck Model
- k10
- Engine Size
- 350
alright i borrowed this from a jeep forum that i used to frequent before i bought my square, all credit goes to KTMRACER419 over at jeep cherokee forum. hotrod should make this a sticky as it is full of useful info 
First off I do not consider myself an expert on the matter, but I have a few years experience in "low cog" rig setups. I often have people asking me "ZOMG HOW DO YOU GET ALL THAT FLECKS WITH THOSE BIG TARZ AND LITTLE LIFT!?!?!11!!77!" so i figure its a good time to make a thread I can point people to when i am asked this question.
I will make this post in a frequently asked question format, and as more specific questions arise, I will add to it accordingly.
_____
Why do I want a low lift height?
A low lift height has many advantages over a taller lift height. Don't get me wrong there are a billiondy situations you will encounter offroad and no rig is perfect in each situation, and much of this boils down to personal preference. With that said a lower lift height has 2 main benefits:
-adds stability, both off camber, while on hillclimbs and hill descents
exhibit A, drove out of it
exhibit b, drove up it
-better handling at high speeds and on the street
exhibit c, can safely blow a kiss to the camera while maintaining highway speeds
2 main downfalls:
-less belly clearance, breakover, and departure angles
-less suspension compression (only a real issue when you get into high speed stuff)
______
wouldnt it be better to have a bigger lift for more flex?
Flex isn't limited by suspension height, its limited my the components you use in your suspension. Bigger lifts call for more components to be safely run at that height, and this is why an out of the box 3" kit won't net you the same flex as an out of the box 6.5" longarm. Put many of the components from the 6.5" longarm lift on your 3" springs, and you will have a rig that flexes very similarly to it's taller counterpart (in many cases even better).
A flatter leaf spring allows more suspension travel than a taller, highly arched leaf spring. With a linked type suspension a flatter control arm angle will allow superior suspension droop over a control arm that is already at a steep angle to begin with.
______
Wouldnt bumpstops severely hurt my flex?
While it is true that bumpstops will keep your suspension from compressing, it doesn't necessarily have to HURT your flex. If you are running a 3" lift generally they come with 8" travel shocks, and these lifts are designed to stop compressing before the shocks bottom out. But if you add 2" more bumpstop to this, you can effectively run a 10" travel shock with no fears of bottoming them out. If the rest of the components in your suspension are up to it, the 2" of travel you lost in compression, you more than regained with 4" of added droop.
Now i'm sure some will ask, "How does getting 2" more shock travel mean 4" more droop? But when you add the 2" of extra bumpstop, and the 10" travel shock, the body of the shock is about 2" longer, so it cannot compress that 2" we lost in the uptravel department. The added 2" longer body, combined with the 2" extra travel will allow this 4" of extra droop.
Bumpstops can also help your flex, if you have any bind in your suspension (running a 4 link, or radius arm design in most cases) the solid axle acts as a see-saw, with the bumpstop as the pivot point. once one side of the axle contacts the bumpstop, the other side will begin to be forced down. This "see-saw" action will continue until a suspension component on the drooping side limits it (usually a shock).
exhibit D, 3" lift and 36" iroks
______
I have 32's with a 6" lift and STILL rub at full flex, how do you get away with it?
Bumpstops. Lift height doesn't make your wheel openings larger, trimming does, if you are afraid of trimming, you will just need to bumpstop a great deal. Some rigs can get away with it though by running stiff springs.
______
I can't get my leaf springs to flex as well as my coils, what can I do?
First you need to admit that you arent going to get a conventional leaf spring setup to flex as well as the front linked suspension found in jeeps. But you can still get the back end to do a decent job back there. Firstly, most off the shelf lift kits are tuned mostly for suspension compression. While running large tires on that lift in small wheel openings (specifically xj's) you will have to limit your uptravel. You can either cut open your xj body and do some fabrication, or decide to make your suspension droop. Keys to this are running as flat leaves as possible and having a good shackle angle. A good shackle angle is one that is about 45 degrees acute to the leaf spring, this still allows for some compression, but allows for MUCH more unrestricted droop, as well as a nicer ride quality. You can get a decent shackle angle by either running longer leaf springs, or relocating the upper mounting point forward on the vehicle, there are weld-on reloaction brackets available.
As for the leaf pack itself. a pack consisting ofseveral thin leaves yields the best results for flex. and more leaves will also aid in keeping axle wrap under control. Some people go the extra mile and coat the leaf springs with a special anti-friction paint before leaf pack assembly as well.
______
What is limiting my front suspension's flex?
There are too may scenario's here for me to list them all. but i'll run through the stock components that will hinder flex. This pertains to a stock xj 4 link front end with a dana30 axle.
1- stock front swaybar. get swaybar disconnects or remove it for the trails.
2- stock shocks (when you do this remember to lengthen your brake hoses as well)
3-lower control arms. it's not the bushings that hurt the flex, but the fact that they hit the shock mounts on the stock dana30 front end will limit your suspension droop. most aftermarket arms will either have a bend in them or an offset bushing to compensate for this.
4- stock trackbar, there is a certain point where it will either bind at the frame end heim, or the bracket at the axle end.
5- shortarms. time to go to longarms or midarms if you want more flex.
6-stock steering, it isnt adequate for hard wheeling anyway and should have been ditched before the longarms.
_______
What about clearance?
With a lower lift height this can become an issue for some. But there are things you can do about it.
First are to put a skid plate protecting any vunerable component under your jeep. With lockers at each end and a flat belly with high clearance rocker guards I have been able to finesse my way over obstacles and very rarely do I get hung up. Sometimes I even bump the front tires and purposely get the front end up in the air, which has given me mixed results, but sometimes is the only way of getting over some obstacles.
Some high clearance bumpers will also do wonders for your approach/departure angles
exhibit E and F, high clearance rocker panels and bumper
_________
What about going fast? don't I need uptravel for that?
Short answer: yes. You are going to have a hard time building a low cog xj to handle the whoops like a jeepspeed-esque rig, but there are some things you can do to make your time at speed more enjoyable.
1: Springs, the stiffer the spring, the better it will be at speed, this is true for taller rigs as well.
2: PROGRESSIVE BUMPSTOPS. Cannot stress this enough. They made a night and day difference on my jeep at speed.
Exhibit G, rear 2.5" progressive poly bumpstops
For the front the best bet on a budget is prothane coil spring inserts.
http://www.jegs.com/p/Prothane/Proth...62178/10002/-1
Of course airbumps are the god of progressive style bumpstops, but that is a whole different thread.
3:SHOCKS.again, true with tall suspensions as well, you need to keep that unsprung weight under control. I'm no shock pro, but a fairly stiff valving and the most fluid capacity possible helps greatly.
exhibit H, approximately 2.5" and 36's with progressive poly bumpstops
_________
What about my pretty fenders? Do i have to hack them up?
If you want to run large tires, you need to trim your fenders regardless of lift height. Taller springs won't make your wheel openings magically larger. They just prolong the time it takes for the tire to get there. And just because you need to trim your fenders, doesn't mean they have to look ugly either
exhibit I
depending on your control arms and tire size however, there is an inner pinch seam that needs to be sliced and pounded flat up front to keep the tire from contacting it. This is an easy job and takes all of a few minutes.
What exactly are the benefits of a flatter control arm angle?
This is broadening the topic at hand, but still relates to low cog suspension setup.
In short my biggest complaint from running shortarms is approaching ledges. in order for the front suspension to compress the back tires need to slip backwards.
Imagine a tall shortarm lift. The control arms are at a 45* angle and you approach an obstacle at greater than a 45* angle. The only way the front suspension will compress is if the other drive tires slip backwards. Same if you have control arms at a 30* angle and the obstacle is greater than a 70* incline. The front suspension will want to stay unloaded until those tires are up and over that obstacle/ledge. This can make for some interesting 3 wheeled moments with the front end up in the air. The flatter the control arm angle, the more unrestricted the movement, and the steeper the obstacle you can climb while keeping all 4 tires firmly planted. It is also less stressful on steering components and axles.
Exhibit J,
Aside from that there are the obvious ride quality improvements along with more unrestricted articulation.
First off I do not consider myself an expert on the matter, but I have a few years experience in "low cog" rig setups. I often have people asking me "ZOMG HOW DO YOU GET ALL THAT FLECKS WITH THOSE BIG TARZ AND LITTLE LIFT!?!?!11!!77!" so i figure its a good time to make a thread I can point people to when i am asked this question.
I will make this post in a frequently asked question format, and as more specific questions arise, I will add to it accordingly.
_____
Why do I want a low lift height?
A low lift height has many advantages over a taller lift height. Don't get me wrong there are a billiondy situations you will encounter offroad and no rig is perfect in each situation, and much of this boils down to personal preference. With that said a lower lift height has 2 main benefits:
-adds stability, both off camber, while on hillclimbs and hill descents
exhibit A, drove out of it
exhibit b, drove up it
-better handling at high speeds and on the street
exhibit c, can safely blow a kiss to the camera while maintaining highway speeds
2 main downfalls:
-less belly clearance, breakover, and departure angles
-less suspension compression (only a real issue when you get into high speed stuff)
______
wouldnt it be better to have a bigger lift for more flex?
Flex isn't limited by suspension height, its limited my the components you use in your suspension. Bigger lifts call for more components to be safely run at that height, and this is why an out of the box 3" kit won't net you the same flex as an out of the box 6.5" longarm. Put many of the components from the 6.5" longarm lift on your 3" springs, and you will have a rig that flexes very similarly to it's taller counterpart (in many cases even better).
A flatter leaf spring allows more suspension travel than a taller, highly arched leaf spring. With a linked type suspension a flatter control arm angle will allow superior suspension droop over a control arm that is already at a steep angle to begin with.
______
Wouldnt bumpstops severely hurt my flex?
While it is true that bumpstops will keep your suspension from compressing, it doesn't necessarily have to HURT your flex. If you are running a 3" lift generally they come with 8" travel shocks, and these lifts are designed to stop compressing before the shocks bottom out. But if you add 2" more bumpstop to this, you can effectively run a 10" travel shock with no fears of bottoming them out. If the rest of the components in your suspension are up to it, the 2" of travel you lost in compression, you more than regained with 4" of added droop.
Now i'm sure some will ask, "How does getting 2" more shock travel mean 4" more droop? But when you add the 2" of extra bumpstop, and the 10" travel shock, the body of the shock is about 2" longer, so it cannot compress that 2" we lost in the uptravel department. The added 2" longer body, combined with the 2" extra travel will allow this 4" of extra droop.
Bumpstops can also help your flex, if you have any bind in your suspension (running a 4 link, or radius arm design in most cases) the solid axle acts as a see-saw, with the bumpstop as the pivot point. once one side of the axle contacts the bumpstop, the other side will begin to be forced down. This "see-saw" action will continue until a suspension component on the drooping side limits it (usually a shock).
exhibit D, 3" lift and 36" iroks
______
I have 32's with a 6" lift and STILL rub at full flex, how do you get away with it?
Bumpstops. Lift height doesn't make your wheel openings larger, trimming does, if you are afraid of trimming, you will just need to bumpstop a great deal. Some rigs can get away with it though by running stiff springs.
______
I can't get my leaf springs to flex as well as my coils, what can I do?
First you need to admit that you arent going to get a conventional leaf spring setup to flex as well as the front linked suspension found in jeeps. But you can still get the back end to do a decent job back there. Firstly, most off the shelf lift kits are tuned mostly for suspension compression. While running large tires on that lift in small wheel openings (specifically xj's) you will have to limit your uptravel. You can either cut open your xj body and do some fabrication, or decide to make your suspension droop. Keys to this are running as flat leaves as possible and having a good shackle angle. A good shackle angle is one that is about 45 degrees acute to the leaf spring, this still allows for some compression, but allows for MUCH more unrestricted droop, as well as a nicer ride quality. You can get a decent shackle angle by either running longer leaf springs, or relocating the upper mounting point forward on the vehicle, there are weld-on reloaction brackets available.
As for the leaf pack itself. a pack consisting ofseveral thin leaves yields the best results for flex. and more leaves will also aid in keeping axle wrap under control. Some people go the extra mile and coat the leaf springs with a special anti-friction paint before leaf pack assembly as well.
______
What is limiting my front suspension's flex?
There are too may scenario's here for me to list them all. but i'll run through the stock components that will hinder flex. This pertains to a stock xj 4 link front end with a dana30 axle.
1- stock front swaybar. get swaybar disconnects or remove it for the trails.
2- stock shocks (when you do this remember to lengthen your brake hoses as well)
3-lower control arms. it's not the bushings that hurt the flex, but the fact that they hit the shock mounts on the stock dana30 front end will limit your suspension droop. most aftermarket arms will either have a bend in them or an offset bushing to compensate for this.
4- stock trackbar, there is a certain point where it will either bind at the frame end heim, or the bracket at the axle end.
5- shortarms. time to go to longarms or midarms if you want more flex.
6-stock steering, it isnt adequate for hard wheeling anyway and should have been ditched before the longarms.
_______
What about clearance?
With a lower lift height this can become an issue for some. But there are things you can do about it.
First are to put a skid plate protecting any vunerable component under your jeep. With lockers at each end and a flat belly with high clearance rocker guards I have been able to finesse my way over obstacles and very rarely do I get hung up. Sometimes I even bump the front tires and purposely get the front end up in the air, which has given me mixed results, but sometimes is the only way of getting over some obstacles.
Some high clearance bumpers will also do wonders for your approach/departure angles
exhibit E and F, high clearance rocker panels and bumper
_________
What about going fast? don't I need uptravel for that?
Short answer: yes. You are going to have a hard time building a low cog xj to handle the whoops like a jeepspeed-esque rig, but there are some things you can do to make your time at speed more enjoyable.
1: Springs, the stiffer the spring, the better it will be at speed, this is true for taller rigs as well.
2: PROGRESSIVE BUMPSTOPS. Cannot stress this enough. They made a night and day difference on my jeep at speed.
Exhibit G, rear 2.5" progressive poly bumpstops
For the front the best bet on a budget is prothane coil spring inserts.
http://www.jegs.com/p/Prothane/Proth...62178/10002/-1
Of course airbumps are the god of progressive style bumpstops, but that is a whole different thread.
3:SHOCKS.again, true with tall suspensions as well, you need to keep that unsprung weight under control. I'm no shock pro, but a fairly stiff valving and the most fluid capacity possible helps greatly.
exhibit H, approximately 2.5" and 36's with progressive poly bumpstops
_________
What about my pretty fenders? Do i have to hack them up?
If you want to run large tires, you need to trim your fenders regardless of lift height. Taller springs won't make your wheel openings magically larger. They just prolong the time it takes for the tire to get there. And just because you need to trim your fenders, doesn't mean they have to look ugly either
exhibit I
depending on your control arms and tire size however, there is an inner pinch seam that needs to be sliced and pounded flat up front to keep the tire from contacting it. This is an easy job and takes all of a few minutes.
What exactly are the benefits of a flatter control arm angle?
This is broadening the topic at hand, but still relates to low cog suspension setup.
In short my biggest complaint from running shortarms is approaching ledges. in order for the front suspension to compress the back tires need to slip backwards.
Imagine a tall shortarm lift. The control arms are at a 45* angle and you approach an obstacle at greater than a 45* angle. The only way the front suspension will compress is if the other drive tires slip backwards. Same if you have control arms at a 30* angle and the obstacle is greater than a 70* incline. The front suspension will want to stay unloaded until those tires are up and over that obstacle/ledge. This can make for some interesting 3 wheeled moments with the front end up in the air. The flatter the control arm angle, the more unrestricted the movement, and the steeper the obstacle you can climb while keeping all 4 tires firmly planted. It is also less stressful on steering components and axles.
Exhibit J,
Aside from that there are the obvious ride quality improvements along with more unrestricted articulation.
