what link material?

doing a 4-link setup rear and hopefully front with coilovers and stretch front and rear. I will be using Johnny Joints with 1 1/4 threaded shaft lowers and 1" threaded shaft uppers.
What should I use for the link material?
1. Aluminum 2" lowers and 1.75" uppers and have them drilled and threaded.
2. DOM with threaded inserts with 2" diameter x 3/8 thick lowers and 1.75" x 3/8 uppers?

Any other options? I fear with aluminum it may shatter if tweaked too much like I've seen on videos past whereas DOM can bend but not break.

Is aluminum used for more strength or mainly just for weight? I would think your better off going with DOM and inserts. That way you have full control of the Fab work. With the alum. links you have to wait to order them till you do all your mock ups and then if you want them changed you have to send them back out. Also the added cost. If you were building a light weight rig I would say yeah don't cut yourself short and get the lightest, strongest you can get.

good point. this is not going to be a lightweight rig. I was recommeded the aluminum for strength compared to DOM and the (weak) threaded inserts. I like the idea of being able to do the work myself and could fix it myself if there is breakage. I have seen aluminum shatter but havent seen a threaded insert come apart. I've seen DOM bend but at least you could get off the trail.

Price for DOM is way cheaper. ALuminum stock is $27/foot for 2" 2024 and $18 for 6061. DOM is like $4-5/foot for 3/8"

You could always get DOM in a wall thickness that all you have to do is thread the DOM for your ends its heavier but stronger and much harder to bend and fail.

Or chromoly tubing lighter but still strong, and cheaper than aluminum

alot of people use 2x2 1/4 wall square strong as hell and alot cheaper than the dom or chrom not a big fan of the alum its solid so if the threads fail u replace the bar not just a tubing bung

SPP YJ wrote:

You could always get DOM in a wall thickness that all you have to do is thread the DOM for your ends its heavier but stronger and much harder to bend and fail.

Or chromoly tubing lighter but still strong, and cheaper than aluminum

What size would I use to do that? I thought they used solid links in order to drill/tap threads.

Chrom tubing is not lighter its stronger it weighs the same as dom they use thinner in racing that way its lighter .balistic fab seems to have good prices on tubing bungs look at the wall thicknesses they have listed to match up the tubing size remember dillsburg doesnt usually carry real thick wall tubing

take a look at the video that clayton posted that has clayton\'s buggy breaking the link it wasn\'t the aluminum link that broke it was the jj. one of the new jersey guys ripped out a tubing insert during the RCQ. ballistic makes a racing type insert that is longer so you can put multible plug welds to better hold it in. I would do DOM with those inserts, but if I had the money I would go with aluminum or thin wall cromo. A lot of people run 7075 aluminum. I don't really know what that means but I guess it is a stronger grade then 6061 so it will probably be even more. square is heavy and I kinda think it looks kinda hill-billy, no offence to people that run it . And sqaure tubing does bend ask me how I know

http://www.ballisticfabrication.com/Race-Style-Chromoly-125quot--12-tpi-Tube-Adapter-15quot--175quot_p_1545.html

also this might be worth reading if you do go with aluminum

http://marylandcreepers.com/showthread.php?t=1692

thats bend redneck

edited cause I'm dumb

Bill, I would build it to throw it away. From what i have seen, just about anything out there is prone to failure under the right condition, or if you abuse it long enough. I would go in with the idea that it was going to have to be replaced any way due to wear and tear, i would go with the easiest and cheapest to replace. Especially with rock racing, something will break every time your out and seeing that your not even trying to place, why not keep it cheap on your wallet.

check these joints out. 60 degree of flex instead of a jj at 35 degree. also has the 1.25 thread with a 3/4 bolt thru
http://www.summitmachine.com/index.php?p=customParts&cp=jj
THEY LOOK PRETTY BEEFY

THEY ARE ALSO REBUILDABLE

I've seen those before. I like the JJ because they are rebuildable and fairly dependable. Won't need a lot of flex and the JJ should be good enough. I'm really liking those LONG weld in bungs.

THEY ARE ALSO REBUILDABLE. KIT IS LIKE 15.00......BUT THEY SEEM TO BE MORE MONEY AS WELL

bill i think that the best thing would be Alumi lowers & dom uppers & try to make all lowers & uppers same length front & rear that way u only need 1 spare upper & lower to save cost

MonsterS10 wrote:

bill i think that the best thing would be Alumi lowers & dom uppers & try to make all lowers & uppers same length front & rear that way u only need 1 spare upper & lower to save cost

Do you have the equipment to drill and tap solid aluminum to build these links?

can do i'll get price on materials also might be cheaper

Thanks that would be greatly appreciated. I have all the Joints from Randy. using 1" on the uppers and 1 1/4 on the lowers.
2" for the lowers and can do DOM for the uppers as you suggested. Guessing .250 should be fine with 1.75 OD.

My links are all 7075 Alum... using 2" for the lowers, and 1.75" for the uppers.. Joints are the Currie forged Johnny Joints with a 1" shank on the uppers and 1.25" shank lowers.

I went with Aluminum because:

1: It's significantly stronger than 2" .500" DOM
----- 2" 7075 AL link in my length takes 6800lbs to bend permanently, weighs 11lbs.
----- 2" .250" DOM link in my length takes 3200lbs to bend permanently, weighs 13lbs.
----- 2" .500" DOM link in my length takes 4350lbs to bend permanently, weighs 22.5lbs.
----- 2" .250" 4130 CroMo link in my length takes 4000lbs to bend permanently, weighs 11lbs.
----- 2" .500" 4130 CroMo link in my length takes 5500lbs to bend permanently, weighs 22.5lbs.
2: I was trying to save weight where I could without sacrificing strength and longevity (How many 2-seater 4WS rockwell rigs have you seen that weigh 4600?) I saved ~80 lbs in link material alone.
3: It wasn't THAT much more in the end than DOM + inserts, and was less than 2" .500 CroMo (Which I would have drilled and tapped)
4: No weld to fail. (minor reason)

I have landed directly on the links several times (Can Opener at Harlan is a prime example) and you feel it give ever so slightly, makes the landing a little nicer. The difference is, when steel bends, it tends to stay bent. Aluminum is easier to bend, but comes right back to shape, which is why 7075 is what the landing skids on a Huey are made from...

If you get AL links, do NOT taper the ends, keeping them full diameter gives the jam nut a good surface to grab onto, and keeps the wall thickness good around the threads.

Just my $.02..

wow did your research on that didn't you

MonsterS10 wrote:

wow did your research on that didn't you

I tend to over-research things. I'm kind of a sponge for information, when it interests me. (Which is why I'm here right now instead of doing work.. ssshhhh

I can get 7075-T6 2" extruded T6511 round bar stock for $14.83 per foot or cold finished T651 for $21.50 per foot. We use a lot of exotic/ semi-exotic materials here at work and can get pretty good prices on it.

the 1.75 7075 alum for me is 18.77 per foot

WOW I like My leaf springs, I can deal with the harsh ride

Since the Alum comes in 12' lengths as a full stick, you might get a cost break for buying the whole length..

I think mine was the T6511, if I remember right.