Topic: 4link Geometry/Design Check my layout! Info

[zippo]

So I am thinking while lifting/rebuilding/SASing my 88 Excab I might 4 link the rear end. I have done some research/layout on paper and think what i came up with will work rather well. I plan on driving the truck on the road and offroad, Rocks, Trails, Etc...

Here is a link to a large pic of the layout, much easier to read and see

http://oppiz.net/pics/yota/4link%20Diagram%5bLarg%5d.JPG

Here is a smaller pic of it.

<img src=http://oppiz.net/pics/yota/4link%20Diagram%5bSmall%5d.JPG >

This will be my first 4link, but everything i have read says this should be ok. But is a 60" lower link to much?

Let me know what all you think?

[snowshoebrue]

60" lowers are pretty long, have you checked the clearance  of the lowers on your t-case?  my lowers are 50 and they are pretty close to the back of my t-cases and i have a longbed

edit*  hard to tell are you building the links down 4"?  



heres is mine

[zippo [OP]]

i was going to drop the lower link hanger 4" so it could sit under the TCase, are could even be constructed into the TCase mount. I might try to redesign it again. This just seemed to fit/work well to i would get some feedback. Kepp em coming!

[snowshoebrue]

just keep in mind that the hanger will be more likely to hang up on obsticles.  have you read up on calc. 4 link on pirate?
http://www.pirate4x4.com/forum/showthread.php?t=168577&highlight=link+calculator
http://www.pirate4x4.com/forum/showthread.php?t=204893&highlight=link+calculator

[zippo [OP]]

I have read them. I really didn't like the calculator. But have done tons of reading and used

http://www.4wheeloffroad.com/techarticles/suspension/131_0307_four_link_suspension_part_2/index.html

Todo my layout. I changed it slightly and got the bottom link down to 52" and flush woth the frame bottom.

[TacoRunner]

60" is way to long you will be draging your lower links on everything and it will make ledges/stairs very difficult Shoot for 40" lowers and 30" uppers.

[TacoRunner]

This will be my first 4link, but everything i have read says this should be ok. But is a 60" lower link to much?

Let me know what all you think?

Personally, from what I've read, your link design will work fine, nothing about it is wrong. My feelings on it and in general are, I dont think we need to keep the links tucked up past the frame if they are converging toward the T-Case. That is, mounts that are located under the frame like a spring hanger from a leaf spring set up are much more likley to hit and hang up on rocks then stuff that is the same distance to the ground but are in toward the center of the truck. My lowers are the same height as my T-case. But because they are pulled in toward the center, they dont hang up on stuff.

[Sleeve of Wizzard]

http://www.4wheeloffroad.com/techarticles/suspension/131_0306_four_link_suspension_part_1/index.html


Found this while doing some research 

[TacoRunner]

This article only gives a portion of the story. It is a great starting point but there is alot of other info out there.

[zippo [OP]]

Yeah. I priced it and its just to much out of the budget. I can always go back and add it. But its good to know about.

[Steve_925]

60" is way to long you will be draging your lower links on everything and it will make ledges/stairs very difficult Shoot for 40" lowers and 30" uppers.

X2

i first made my lowers 52" and relized that they where too long then went down to 44-48 cant remember, they are still a little long. my front links are 36" from tube adapter to tube adapter so they prabable measure out 42? eye to eye. to me what i've kinda figured out is not to go much more than a couple inches longer than your tire size, its kinda a good rule of thumb i thought of.  i would also try at the least to keep the top of your joint level with the bottom of your frame, if not higher.

[Steve_925]

before i shortened the linx



after

[TacoRunner]

 i would also try at the least to keep the top of your joint level with the bottom of your frame, if not higher.

Thats the only part I'd disagree with. IMO, you just want flat links. If you have a low ride height, like you do, then you can get away with your heims being tucked up that far. Other wise leave them low and build them to slide over stuff.  

[zippo [OP]]

When trying to lay out the design, i found the large the tire/more lift the more compromise had to be given to everything.

[TacoRunner]

In what regard?

[zippo [OP]]

Link length/angle, frame mount location and axle mount separation. And your willingness to mod the bed.

[Steve_925]

Thats the only part I'd disagree with. IMO, you just want flat links. If you have a low ride height, like you do, then you can get away with your heims being tucked up that far. Other wise leave them low and build them to slide over stuff.   

agreed