4 link Bars

[Juan_Hong_Loe]

I got a question, I was thinking about using 7075 for my rear lowers they are 4' long and I know they will eventually get bent , but after they are bent how hard would it be to straighten them out or would that be bad to even try?? I know alum likes to crack when it bends.

Once it's bent, if you bend it back it actually makes it weaker.

 

[crawler1]

My hole idea behind the hex .is for looks . I Have been thing about making them hex, with a twist from one end to the other . Round is much easier with just wrench notches .Its going to be a few weeks be for i get it any way. I did get my 30 sticks of 1 3/4 x .120 and m 10 sticks 1 3/4x.095 and 5 - 4 x 10 sheets of .125 aluminum , and 5 sheets of 4 x 10 . 0625 today for my frame and body ..

 

[millerxc]

I would really like to try the 7075 just for the weight diff, I run 2.25 x .500 now and they are almost J shaped and really heavy, just not convinced its worth the money yet, if I spent 400 bucks and bent them pretty quick I'd be

 

[blacksheep10]

Ryan, it is unbelievably tough. It is hard to permanently bend one, even though you may bow it 6" on something, it pretty much always comes back. Some 2.5" on yours should last for a LONG time.

 

[crawler1]

Have you ever heard of 7000-HR-T651 aluminum . It is calmed to have a Tensile Strength ( psi ) of 78,320 . Were as for 7075-T651 aluminum has a tensile strength ( psi ) of 58,000 . According to aircraft Quality specks . Know any thing on this ?

 

[Cole]

Man just go with 7075. It's proven. If you have doubts run 2.5 lowers. I have 2.25 lowers and 2" uppers and they are huge.

 

[crawler1]

OK . I guess i am trying to make a bigger deal out of this than it is .. I can always make more bars .. .. So 2.50 uppers and lowers it is ..

 

[Cole]

OK . I guess i am trying to make a bigger deal out of this than it is .. I can always make more bars .. .. So 2.50 uppers and lowers it is ..

Cool, so what are these going on. 2.50 uppers are gonna be massive. Hell I thought my 2" uppers and 1 1/4 joints with 1" bolts were big.

 

[crawler1]

I am building two new Rides . You might have seen my jeeps at gray rock , up in the top parking lot were you first come in , with the huge enclosed trailer and truck . One has the body of a Tj , and one has part of the body of a Yj . I have been thinking about chopping up my body , but it is way to nice to cut up , and destroy . I wheel pretty much every weekend , and 2 -4 times a week at night after work . Running to local spots and trails , Threw the woods ,and local mountains .. I will be starting a build page on here some time in the next few weeks when all my parts get in and i get it all lined up and ready to go .. Basically Im just cutting down the weight of my ride, and i want some thing that i feel safe in if i do roll over again .

 

[blacksheep10]

I am building two new Rides . You might have seen my jeeps at gray rock , up in the top parking lot were you first come in , with the huge enclosed trailer and truck . One has the body of a Tj , and one has part of the body of a Yj . I have been thinking about chopping up my body , but it is way to nice to cut up , and destroy . I wheel pretty much every weekend , and 2 -4 times a week at night after work . Running to local spots and trails , Threw the woods ,and local mountains .. I will be starting a build page on here some time in the next few weeks when all my parts get in and i get it all lined up and ready to go .. Basically Im just cutting down the weight of my ride, and i want some thing that i feel safe in if i do roll over again .

uppers are just loaded linearly, smaller OD required. Only reason for big boys down low is side loads. 2" OD is huge compared to most.

 

[Welderd]

travis, what about round with the same od as the cross measurement, like 2" across the corners is 2.828. who wins then? I would have to say round by far. Granted that is a lot more weight and expense, just curious.

yup the round would win then

it's all about the amount of material at the extreme fiber (material at top and bottom).
As far as different shapes goes it's all about the moment of inertia
to make your brain hurt - http://en.wikipedia.org/wiki/Moment_of_inertia

simplify all that into:
square I = (b x h^3) / 12 - http://www.engineersedge.com/calculators/section_square_case_6.htm
round I = (pi x d^4 ) / 64 - http://www.engineersedge.com/calculators/section_square_case_11.htm



Now as far as 7000 AL
The first number is the series or family that the aluminum is in. 7 thousand series are all in the same "family" and will have similar material traits. I haven't looked up what 7000 is so I don't know for sure but if your tensile strength numbers are correct then it would be stronger but there would be other things to check for to see how they compare to 7075.
cost, hardness, fracture toughness and some others. 7075 is proven in our applications so just use that as a baseline.

 

[Welderd]

Lastly

Be careful when machining AL links. most all the AL that people use is strong enough in bending. But I broke one from shear, the ends were tapered too much and there wasn't enough wall thickness were the threads and tapped hole was.

I've also seen a few break similarly from using 1.25" heims not sure what diameter of AL but it wasn't enough.

I basically had 1.5" tapped for 7/8" and it took a really good hit right at the end of the heim threads - you couldn't have placed it any better for failure

 

[crawler1]

uppers are just loaded linearly, smaller OD required. Only reason for big boys down low is side loads. 2" OD is huge compared to most.

I am running a double triangulated suspension right know , and plan on using it on my new rides . Is this any stronger than a standard single triangulated suspension . My only reason for this is that my spider trax front end turns 50 deg. and it hits the bars other wise .

 

[Welderd]

not necessarily stronger but the links that are triangulated will have linear loads on them to locate the axle from side forces
with a double triangulated 4 link these are more evenly shared between the links (ie 4 instead of 2) but it's not enough difference to matter good or bad

 

[crawler1]

All right Just got my bar ordered , i thoguht it was pretty good on price . 7075-T651 aluminum solid bar.

16 ' - 2 1/2 ''
16' - 2 ''
11' - 2 1/4 '

Shipping and all was right at one thousand dollars for all , I didn't think it was to bad ..

 

[Glen1978]

Where are you guys getting this stuff at? I talked to Branik today....They wanted nearly $1800 shipped for (8) 2.25" links that were all 4' long(just trying to get a rough estimate of what these 7075 links are gonna cost). Tapped for 1.25" heims, all right hand thread.

After reading this thread Im wondering if 2.5" wouldnt be better for me. Rockwells, 6.0L, 47's and a size twelve right foot....?

Who are you guys using to do this. I dont mind paying but I thought that was alittle high. That would put me around $2500+ in all my links

 

[BamaTJ]

The material jumps in price all the time, kinda hard to say what is good and bad. You can always buy it and drill/tap yourself and it will be cheaper

 

[blacksheep10]

not cheaper when you break a tap or 2 in AL. AL is semi volitile right now.
in JAN it was 2/3 what it is now. Branik is fair and a good judge for what the market is

 

[Glen1978]

Yeah I sure I can drill/tap or have a buddy at a maching shop do it. I looked online today and found a few places.

onlinemetals.com had 2.5" 7075 T651. For (4) 96" links (cut them in half) it was $1304.40 shipped. Not too bad. If I stepped down to 2" top links the price would go down to $1147 shipped.

They only had 2" or 2.5", no 2.25" stuff.

What do you guys think is the best way to drill/tap this stuff at the home shop? No lathe here.

 

[blacksheep10]

What do you guys think is the best way to drill/tap this stuff at the home shop? No lathe here.

honestly, don't. lathe drills it straight and you buy a $85 tap and F it up you buy another 2 holes later. There are guys that will do it reasonably. $20 a hole is going rate.