home made long arm ideas

[prariepunk]

Ok... so here it goes I have a million ideas & only 2 cents... this is a long term idea gathering build... I'm looking to build my own long arm sus for my TJ. I grew up (kinda) in the mud but that's gotten old & expensive... I have a good 4 link calc. (<- I think) Adobe - SVG - Manual Download, but that's about it... I know there are some really good builder/fabricators on here but EVERYONE'S ideas are welcomed!!! I don't want a kit simply because I think they are over priced (but what do I know, lol)... I was thinking on going with DOM 2.25" tube for the lowers with threaded ends for JJs...
The questions I have are:
1: What would be good for uppers & should I use the stock locations on the axle?
2: Should the lowers be as long as the drive shaft?
3: Since this won't happen until she's no longer my DD, should I try to stretch the WB a li'l?
any tips, tricks &/or ideas are very welcomed!!!

 

[prariepunk]

I got this response from another board...

2" .25w DOM is a good size for lowers and with the 1.5" ID, allows for 1.5" OD 1.25" ID thread inserts for the 1.25" shank JJ's. 1.75" x .125w tube will work well for the uppers. As for the mounts, you'll want to address the axle end as well. The lower mounts hang way too low and the upper mounts will be too low. At that point, there's no reason to keep the track bar so triangulation in at least the uppers will be needed. Also, when going longer and putting the mounts where they need to be on the frame, you'll likely run into clearance issues with the tub (and uppers) and the frame (lowers), all dependent upon how long the arms are and where they're mounted of course. I'd suggest doing some good research on link suspension geometry and reading some build threads where this topic is covered.!

 

[bugleboy]

i really wish i coul help but



when it comes to this stuff im clueless

 

[bugleboy]

i like the idea though

 

[jps4jeep]

Your other board response it pretty darn good. Simply since you arking this question, I would abandon the idea of a tringulate 4 link (single or double) with a stock frame rails, it is very hard to package everything around the motor and still maintain a close to stock wheel base. You could go with a three link or build radius arms.

If it was me, and I was building your lowers, I would uses 1.75-.120 and sleeve it with 2.25-.25 DOM. you can use up to a 7/8 shank on your joints. I would use a fixed bushing atleast on one end if this will be your driver.

For uppers, 1.5-.120 is fine.

Ruff Stuff has some good DIY fab kits you should look into as well as mounts and IMHO the best deal on joints around.

 

[prariepunk]

Go with a 3-link??? could it be done in the front? I realize I may have to remove the gas tank & install a fuel cell in the rear...

this isn't going to be my DD... I'm trying to get away from mud & focus more on trails & rocks...

 

[jps4jeep]

Go with a 3-link??? could it be done in the front?

Yes, and it will be way easier for the beginner to fab up. two lower links, one upper link and a trac bar.

I realize I may have to remove the gas tank & install a fuel cell in the rear

Depends on what your desired wheel base is and what axles you plan on running. stock wheel base to a 1-2" stretch with a d44 or 8.8 you will have no need to remove the tank.

1-2" stretch with a 14 bolt and es, you will probably have to move the tank.

this isn't going to be my DD... I'm trying to get away from mud & focus more on trails & rocks...

Doesn't matter, better to do it right and make the vehicle safe. have you identified a need for a long arm suspension? if you stay with in 2-2.5" of lift, the short arms will be fine and can still fit a 33" tire. if you want to wheel rocks I would focus more on building some quality axles. lockers and shafts or better axles all together before I even think about building my own link type suspension.

 

[Utah_jeepster]

Zach, doing a three link up front looks good but on the rocks you can run into some problems. Your front axle is your grab axle on the rocks, in a lot of rock hopping its the main axle that grabs the rock and pulls you up till your rear has grip. With a three link, or a radius arm kit this puts a lot of torque on the lower control arm that also has the upper radius arm attached. This type of lift has a high failure rate since this single arm takes the brunt of the torque and pull load.

Since your thinking of building it your self keep in mind you need to know weight distribution from front to rear and center line of your jeep. The position of the cross over of the triangulation and mount points contribute to your jeep getting squat on initial power up and or anti-squat( the amount of sucking down in the rear end as you hit the gas). The main goal is is to be on the slightly on the plus side since any squat on the rocks will lighten your front end.

Stretching your wheel base will help, but now you run into several areas you will need to look into, steering angles are changed and some hard spots show up unless you move the steering gear box or add hydraulic assist. The rear has the gas tank issue, a gas cell is one fix or Gen right has custom tanks for stretched jeeps.
These are some issues you need to look into, hopefully this gives you some place to start.

 

[jps4jeep]

Could not disagree more, if a three link front suspension was so failure prone, why is it the choice of suspension design for the majority of Ultra4 cars? Your in Utah, I assume you are farmiliar with KOH and the beatings those vehicles take.

If you build it properly, a 3 link can be wheeled hard for a long period of time.

I will agree with making considerations for squat, anti-squat, roll center etc.. but after building a number of link suspensions, I have been putting less and less concern into a 4 link calculator and followed some simple measurements with great success.