4 Link Suspension Geometry for different types of Terrain

[Herzog]

I've recently learned that the reason my buggy doesn't do steep verticals very well is because I have built too much anti-squat into my rear suspension. It tends to not soak up the wall hits and throws the back end back down to the ground.

Don't get me wrong, the thing climbs. It does rockpile very nicely (when I find the right stupid line, at 103" WB). It's the waterfalls (Helldorado) and other throttle wall climbs that don't work so well.

After talking with I Lean a little about this, I have found that I do have room to gain more separation in my links at the frame side.

I love the way my buggy does boulder trails and everything else. I am thinking that is because I have a little extra anti-squat in my rear suspension. I also want it to vertical better though. How do I find my optimum? Do 'zero' anti-squat suspensions behave just as good in the large boulders? Will I miss how it is currently setup?

I figure worse comes to worse and I add in a lot of adjustment in the new brackets and find out where it works best for me.

 

[Hickey]

If you've got the room or lots of adjustment, I would shoot for that. When I ran the numbers on mine, even 1" more vert separation at the frame made a significant difference in the AS values... at least on paper.

 

[Herzog]

If you've got the room or lots of adjustment, I would shoot for that. When I ran the numbers on mine, even 1" more vert separation at the frame made a significant difference in the AS values... at least on paper.

I'll have to take a look again, but I think I have enough room to allow for 4" more of vertical seperation. I'll be surprised if I need to go more than 2" higher than it is now.

I never ran my numbers or anything on paper, because I figured that it wouldn't be all that accurate once implemented anyways. I always had a good idea of what I needed to do, but now I'm learning that it could be better.

 

[Hickey]

I would too.

 

[Milner]

My brackets are set with 5 holes 1.5" apart, top hole is the same seperation as the back. Thats where i put it when i built it, and it has never moved. I like it too much there....

 

[Herzog]

My brackets are set with 5 holes 1.5" apart, top hole is the same seperation as the back. Thats where i put it when i built it, and it has never moved. I like it too much there....

Just what I needed to know.

How well does your rig do verticals with equal separation on the links?

 

[I Lean]

In slow crawling, you won't likely notice a difference with the change in your rear links, only on throttle-y stuff.

 

[Milner]

Just what I needed to know.

How well does your rig do verticals with equal separation on the links?

I love the way in climbs....not a comp rig with water, but....Decending on the otherhand....I have work to do! Mainly a sway bar/limit strap....Not really the fault of the geometry, just unloads bad!

 

[yellowbronco]

I love the way in climbs....not a comp rig with water, but....Decending on the otherhand....I have work to do! Mainly a sway bar/limit strap....Not really the fault of the geometry, just unloads bad!

Hmmmm, mine unloads going up stuff. Do you run a sway bar setup in the front?

 

[Herzog]

Hmmmm, mine unloads going up stuff. Do you run a sway bar setup in the front?

Another thing I just thought of to consider on your setup: Rear coil-over angles. You have your coil-overs angled toward the back of your vehicle, right? I wonder if this has an influence at all...

 

[420willys]

i am by far no expert on how to dial in a 4 link since as we speak i am building one now for my YJ. anyways from what i have read and saw in persion ( east coast wheeling might be different ) is 103'' is great for rock piles and mostly anything in between but for climbing 105 and up is better. i am basing this on the rigs in my group, where most are 101-103'' but we have two guys that are are 105'' and 106'', they ( of course ) can out climb us. now flip side is the cant handle the rock piles like we can, so agin this info might be useless and all well known but i am still learing the 4 link, jason.

 

[I Lean]

Hmmmm, mine unloads going up stuff. Do you run a sway bar setup in the front?

Unloads front or rear when climbing? I'm assuming front, cuz pretty much anything will unload in the front just due to the weight transfer to the rear, which is why you see either a center limit strap or a winch rope attached to the axle. (it makes a much bigger difference than you'd think--ask Cody)

 

[Cody]

Unloads front or rear when climbing? I'm assuming front, cuz pretty much anything will unload in the front just due to the weight transfer to the rear, which is why you see either a center limit strap or a winch rope attached to the axle. (it makes a much bigger difference than you'd think--ask Cody)

huge. night and day.

last year in my old buggy I was on rockpile and I couldn't get up it for the life of me. I used to be able to crawl right up it no problem--maybe just a little baby bump. I was hammering it and it didn't want to go. I finally got up and then realized as we were putting it on the trailer that the front limit strap had broken off the axle.

I remember watching Mike Lib in his WJ giving it absolute hell on rock pile without success--several different days. Then, one day he got fed up and used his winch to hold his front axle and he went up it first shot. It's pretty cool to watch a $50k WJ mallcruiser spank rock pile.

 

[mbryson]

.......I remember watching Mike Lib in his WJ giving it absolute hell on rock pile without success--several different days. Then, one day he got fed up and used his winch to hold his front axle and he went up it first shot. It's pretty cool to watch a $50k WJ mallcruiser spank rock pile.

That is/was a cool 'Jeep'. If it had a 4.0L, it would have had no issues, though.

 

[Cody]

That is/was a cool 'Jeep'.

yes it was

If it had a 4.0L, it would have had no issues, though.

right, cause it wouldn't have made it to the trail in the first place.

 

[Milner]

Hmmmm, mine unloads going up stuff. Do you run a sway bar setup in the front?

Nope, but the front is radius arms, so some built in bind there....
Like Carl said, front will always unload if the climb is steep enough. What wheel base are you running? When I had a semi-close to stock wheel base, climbs could get scarey!!

 

[waynehartwig]

I have yet to try mine out on anything other than the highway, but I built in 84% AS and have 0 body roll. My roll center is also only 30".

My upper links are 29 and 30" from the ground, while the lowers are 22 and 18" (frame numbers first, axle second). This means they are no where near parallel to each other. 7" in at the frame and 12" at the axle.

Send me your email address and I'll send you the 4 link calculator with my numbers already plugged in.

 

[RockMonkey]

I built the rear links on both of my rigs paralell. There is still some antisquat since the links are not paralell to the ground. I have been very happy with both. Every setup I've seen that was built with adjustability ends up set with the links set at the most paralell setting. Do it. You'll like it.

 

[yellowbronco]

Unloads front or rear when climbing? I'm assuming front, cuz pretty much anything will unload in the front just due to the weight transfer to the rear, which is why you see either a center limit strap or a winch rope attached to the axle. (it makes a much bigger difference than you'd think--ask Cody)

I've been experimenting with a front strap, been using crappy straps which have been breaking, but I have noticed a big diference. my bigger problem though is unloading to the side. It seems like the body rolls to the side more than it should effectively lifting a tire and making me appear to be a newbie I don't have anti-sway of any kind, I have noticed that most rigs running a link suspension and coilovers do. Is this the magical answer?

huge. night and day.

When I have a strap that won't break, I will agree

Nope, but the front is radius arms, so some built in bind there....
Like Carl said, front will always unload if the climb is steep enough. What wheel base are you running? When I had a semi-close to stock wheel base, climbs could get scarey!!

I remember the good ol' days of stock. Going down was even scarier I'm at 113 so I don't think thats an issue.
















Sorry for the hi-jack Zoggy

 

[waynehartwig]

I don't have anti-sway of any kind, I have noticed that most rigs running a link suspension and coilovers do. Is this the magical answer?

Someone can correct me if I'm wrong, but doesn't the way you have your shocks valved make this worse/better or even correct it? Granted, if you go to stiff of valving, you will always feel like your at the end of the travel on all up strokes, but it seems like that would eliminate unloading.