atomicjoe23

How do you go about figuring out the correct length of the rear lower 4-link arms. . .I'm building a JeepSpeed Cup/CORR/SCORE inspired desert Jeep XJ and I'm going to be using boxed lower rear 4-link trailing arms and I need to figure out the right length to make them.

JeepSpeed Cup limits suspension travel in the rear to 15" I believe (the JeepSpeed website rules section is not opening at the moment for me to double check) and CORR rules specify a minimum ride height of 10" as measured from the ground to the lowest protrusion on the bottom of the truck (i.e. the truck must be able to drive over a set of 10" blocks with the tires inflated to 20psi). I'm not sure what the stock ride height is at the moment or what ride height that I'm going to be looking for but I'm sure it will be more than 10" but I don't want the thing jacked sky high either. . .looking for more of the desert racer/pre-runner look. Wheel base will be between 104-116" and I'm looking at a front and rear track width of ~70". I will be using 15x10"; 16x10" or 17x9" wheels with either 33x12.50 or 35x12.50" tires and I will have a curb weight of ~3750 lbs. . .give or take.

I'm not sure how much of the above information is necessary but if someone can point me in the right direction as far as customized chassis design goes I would greatly appreciate it.

Thanks!!!

ktmracer419

search for a 4 link calculator on pirate4x4.com or google.

i also thought jeepspeed rules say you need suspension of factory configuration, coils front, leafs rear.

atomicjoe23

JeepSpeed rules do say that you have to do that. . .BUT. . .I'm just building a Jeep Cherokee inspired by these series and am going more custom to meet my personal tastes. . .and I like a the desert racing trophy truck look. . .so I'm gonna be doing a 4-link rear with dual rate coilovers and external bypass shock and a custom IFS front with dual rate coilovers and external bypass shocks based on an '05-08 Tacoma 4WD IFS with a Chaos Fab Uniball long travel suspension kit w/dual shock hoops.

I've seen the 4 link calculator before. . .it's on the Xtreme 4x4 webpage but I hadn't had time to play around with it and figure it out though and it asks for some data that I definitely don't have (if I remember right).

Thanks for the reply.

wheelaholic

why would you build a 4 link rar but put ifs up frot? exspecially in a solid alxe rig? mall crawler?

atomicjoe23

Not gonna see any hardcore rock crawling use and probably not a lot of deep mud use either. . .gonna be a desert/fire road/moderate trail use rig.

I like the look of IFS vs. a solid axle and it's different. . .I like to do things that others haven't done before. . .sets your rig apart from others. . .plus it's fun & cool to make custom set-ups.

It's just a personal preference. . .that's all

wheelaholic

thats completely understandable but im saying for high speeds and such that a jeepspeed sees a rear 4 link is going to have alot of side to side movement even with a trac bar just my 2 cents

atomicjoe23

You think that there will be a lot of side to side movement even with a triangulated 4-link???

Almost all (if not all) of the high end desert racing trucks run with a triangulated 4-link. . .not to mention the CORR series trucks!!!

Maybe I didn't mention that it was going to be a triangulated 4-link before and you just assumed that I meant a standard 4-link vs. a triangulated set-u?

atomicjoe23

Oh yeah. . .and I found out that Dirt-Tech makes a boxed lower trailing arm specifically for Jeep Cherokee XJ JeepSpeeder's. . .it's 50" long from the center of joints.

Now I just have to figure out how long the upper links should be!

vegaslightsss

They make the arms for sure,for just 3k you can own a set (heim joints or pivot brackets not included. I am sorry,they are very nice looking but a pair of bushings,a pair of 1 1/4" heims with bungs a 21' stick of .120 wall DOM and and a 4'X4' sheet of 1/4" plate (Which I have cut at the local water jet place).weld a couple of 5/8" bolts nice and straight onto a strip of steel for a "length Jig" and its very easy if you are capable with a Mig.Just remember to keep you shock mounting points below the centerline of your bushing/heim centerline between the two points so that the arm does not try to "roll" on you and you are in business. For 3k I can have a reasonably well built 9" put together as well. The front of my 3700 is complete and this is exactly where I am in my project right now. I just scored a currie housing with 4 link brackets and all,should have my rear arms built this week,I have to wait another month on my rear shocks yet,Pricey!!Have fun.Vegas