Best adjustable LCA

[Joecey54]

I am planning on buying some adjustable lower control arms. I was just wondering what some of you guys have to say. I am very happy with my techno toy coilovers and TC rods so I was thinking about getting there LCAs. At the same time futofabs are aluminum and I was wondering if that is enough weight to make a difference. I am not worried about comfort just mainly performance and reliability.

everybodys 2 cents it welcome.

 

Thanks

[Trophy24]

I like the Futofab design, but have not tried them personally.

[Mattndew76]

Doesn't Dave do steel and billet arms?

[MicroMachinery]

The ones I bought are from him are steel with an aluminum adjusting sleeve.

[thisismatt]

The tc rod clevice to aluminum connection on the futofab arm would scare me a little...not an issue if connecting the tc to the ball joint as per oem

[DISLEXICDIME]

I have hit a curb at 40 with the arms sinful makes and they are still going strong

[Nuclear Water Boy]

I'm also running FUTOFAB steel adjustable LCA's and I love'm!!! Their adjustability is so simple even a caveman can do it. :w00t:

[Dime Dave]

thisismatt,

What scares you about the clevis connection, is it having just the one bolt tying the TC rod to the LCA?

 

I've had people question how one bolt can properly keep the TC rod attached to the LCA.

 

Here is my explanation.

Using a clevis puts the bolt in double shear. This is the same shear exposure as the stock  LCA to TC rod connection has using 2 bolts in single shear.

 

Next, the bolt used is a properly sized Mil spec AN airframe bolt. What this means is the bolt diameter where it passes thru the shear plane is unthreaded and shear load is applied to the full 3/8" bolt diameter. Having threads in the shear plane reduces strength because of the reduced cross-sectional area of the bolt. Add to this that threads also create stress risers which further weakens bolted connection strength. The AN Mil spec also means the bolt has a 125,000psi tensile strength and a 76,000 psi shear capability.

 

By doing a little math, it can be calculated that a 3/8" AN bolt in double shear is capable of retaining a 16,566 pound load.

 

In suspension design, the calculated load this bolt needs to resist is the braking force of the car. If the front brakes do 70% of the work on a 2,800 # car this means each TC rod is subject to a 980# load at max braking. The typical safety factor on suspension design is 10X. This accounts for sudden impact acceleration as well as a factor for material strength and manufacturing variances. So the max anticipated design load in this case (with a 10X safety factor) would be 9,800 lbs. This bolt is capable of 16,566 lbs or nearly 70% more than the design needs.

[thisismatt]

thisismatt,

What scares you about the clevis connection, is it having just the one bolt tying the TC rod to the LCA?

 

I've had people question how one bolt can properly keep the TC rod attached to the LCA.

 

Here is my explanation.

Using a clevis puts the bolt in double shear. This is the same shear exposure as the stock  LCA to TC rod connection has using 2 bolts in single shear.

 

Next, the bolt used is a properly sized Mil spec AN airframe bolt. What this means is the bolt diameter where it passes thru the shear plane is unthreaded and shear load is applied to the full 3/8" bolt diameter. Having threads in the shear plane reduces strength because of the reduced cross-sectional area of the bolt. Add to this that threads also create stress risers which further weakens bolted connection strength. The AN Mil spec also means the bolt has a 125,000psi tensile strength and a 76,000 psi shear capability.

 

By doing a little math, it can be calculated that a 3/8" AN bolt in double shear is capable of retaining a 16,566 pound load.

 

In suspension design, the calculated load this bolt needs to resist is the braking force of the car. If the front brakes do 70% of the work on a 2,800 # car this means each TC rod is subject to a 980# load at max braking. The typical safety factor on suspension design is 10X. This accounts for sudden impact acceleration as well as a factor for material strength and manufacturing variances. So the max anticipated design load in this case (with a 10X safety factor) would be 9,800 lbs. This bolt is capable of 16,566 lbs or nearly 70% more than the design needs.

 

Hey Dave, thanks for the response.  My concern lies more with the aluminum arm at this connection, but in all honesty I sold my 510 a while back so I'm not really a potential buyer anyways, so take my comments with a grain of salt.  I do like the clevis for the fact that it allows the necessary articulation.  I also tend to go a little overkill on things (tie rod ends seem a little sketch as well in a T/C configuration, but I know a bunch of guys are running them without problems).

[Joecey54]

Would I be able to use my TTT Tc rods with a futofab LCA?

[q-tip]

I have the older style futo fab, arms way more stout than the stock equipment.

 

The aluminium ones look like they are very stout as well.

 

Dave ALWAYS puts out quality parts and his service is top notch

[Nuclear Water Boy]

thisismatt,

What scares you about the clevis connection, is it having just the one bolt tying the TC rod to the LCA?

 

I've had people question how one bolt can properly keep the TC rod attached to the LCA.

 

Here is my explanation.

Using a clevis puts the bolt in double shear. This is the same shear exposure as the stock  LCA to TC rod connection has using 2 bolts in single shear.

 

Next, the bolt used is a properly sized Mil spec AN airframe bolt. What this means is the bolt diameter where it passes thru the shear plane is unthreaded and shear load is applied to the full 3/8" bolt diameter. Having threads in the shear plane reduces strength because of the reduced cross-sectional area of the bolt. Add to this that threads also create stress risers which further weakens bolted connection strength. The AN Mil spec also means the bolt has a 125,000psi tensile strength and a 76,000 psi shear capability.

 

By doing a little math, it can be calculated that a 3/8" AN bolt in double shear is capable of retaining a 16,566 pound load.

 

In suspension design, the calculated load this bolt needs to resist is the braking force of the car. If the front brakes do 70% of the work on a 2,800 # car this means each TC rod is subject to a 980# load at max braking. The typical safety factor on suspension design is 10X. This accounts for sudden impact acceleration as well as a factor for material strength and manufacturing variances. So the max anticipated design load in this case (with a 10X safety factor) would be 9,800 lbs. This bolt is capable of 16,566 lbs or nearly 70% more than the design needs.

Omm! Crap I'm sold. Oh wait I already have a set nevermind.

 

Lou

[Dime Dave]

Would I be able to use my TTT Tc rods with a FutoFab LCA?

 

Yes, no problem.

 

They bolt on top of the ball joint just like an OE TC Rod.

 

Only potential issue could be the ear on the LCA for the FutoFab TC Rod connection. That really isn't a problem because the arms are symmetrical so you just place the ear toward the back and it will be out of the way.