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rturbo 930

New adjustable control arm option from Apex Engineeredd

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Just stumbled on these. Haven't seen these mentioned here, so I thought I'd give you all a heads up. I don't think I've seen anyone sell a control arm with this design before.

 

Anyway, here they are: http://www.apexengineered.com/store/p2/240z%2F260z%2F280z_Rear_Control_Arms.html

 

Looks like it's their first product, too.

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On 12/18/2017 at 10:15 AM, socorob said:

It looks like it has a heim joint on both ends of the back side. Would that be able to move up and down slightly during driving, giving slight caster changes all the time?

The rear rod-end link allows an extra degree of freedom when you add a toe angle other than 0. Rigid H-arm LCAs load up the strut/bushings while rotating instead.

 

The loading in the LCA is much different than the others and this type of A-arm LCA has been discussed/debated extensively on Hybridz, but I believe the general consensus is that it's a superior design. 

 

 

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I love reading through the old discussion threads. 

 

I've thought the same with the extra degree of freedom I think  I even posted on how I didn't understand, and I built my own A-arms. I think we like to look for extra degrees of freedom, but don't factor in things like the strut being bolted in having a limit in movement and length as well as the axles and such.

 

Bottom line is it works, the wheels don't do anything crazy when you accelerate or brake, I do plan on throwing on a camera to try some slow motion of a launch eventually.

 

 

 

 

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The rear link allows the distance between the inner and outer rear pivot points to change as the LCA swings thru it's arc instead of forcing the motion thru the strut. The motion is complicated enough that it's difficult to visualize, at least for me.  I had convinced myself that it worked back when those old threads were active...BUT, I didn't model it kinematically so, there may be a factor that I'm not considering.  In other words, I could have it all wrong! :P

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8 hours ago, Mike Mileski said:

In my opinion they missed the boat by not making the stationary outer rod end "on-the-car" adjustable, like both outer rod ends are on the rear TTT arm.

 

In reality though, how often do you change the track width of the car?

 

Edit: ^sorry that seemed a bit more combative then I meant for it. Genuine curiosity. I can't even come close to say I do many duties with my car, so curious how often does one change the track width? More for different tracks? More for different sets of tires? Or is it just one of those they were there, they could have just added it as a feature type things? Kind of planning my next set of arms and would like to incorporate what I can.

Edited by seattlejester

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It won't move but sure puts a whole lot of constant pressure on the shock rod every time it wants to move...    the strut on our cars is behind the axle center line... every sharp bump first tries to twist the strut, then the strut gives way vertically like it's supposed to...

 

The rigid nature of the factory arms keeps the shock piston side loading to a minimum.

 

Adjustable control arms that put a Hein joint on the inside follow the same principles and don't change much from factory in that regard.

 

You can assemble the strut without a shock and it more or less stays in place if you gently lower your car.  

 

Assemble your strut without a shock with these arms and the spring will twist and may come off the seat as the strut twists backwards with the wheel pushing it up.

 

 

That's not to say it doesn't work well, or that there's ever any issues....

 

That's just my reason for myself not wanting to buy one...   I imagine shock life being significantly shorter...

Edited by Invincibleextremes

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With any MacP strut side load is the enemy, it tends to bind the essential vertical movement of the strut but is an intrinsic part of the design. So anything that reduces side load is good providing the correct geometry is maintained. That's the primary consideration here.

 

What is rarely discussed are low friction design strut dampers. Just as important.

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On ‎1‎/‎16‎/‎2018 at 12:07 PM, seattlejester said:

 

In reality though, how often do you change the track width of the car?

 

Edit: ^sorry that seemed a bit more combative then I meant for it. Genuine curiosity. I can't even come close to say I do many duties with my car, so curious how often does one change the track width? More for different tracks? More for different sets of tires? Or is it just one of those they were there, they could have just added it as a feature type things? Kind of planning my next set of arms and would like to incorporate what I can.

Seattlejester, changing the track width isn't why I'm advocating on the car adjustability. It's to allow the person that is performing the alignment the ability to make adjustments without continually disassembling and reassembling things. What would you do if you mounted these Apex arms and find out that you have to lengthen them a little bit in order to get the exact camber angle you want? You'd have to remove the spindle bolt, turn the rod end a few turns, reassemble it and then remeasure. And what if you didn't get it just right? You'd have to do it all over again. If that rod end was on-the-car adjustable, like the ones that TTT has on theirs, you could do it without all the disassembly and reassembly. Make sense?

 

Mike Mileski

Tucson, AZ

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Dan McGrath and I simultaneously came up with this idea for a control arm. This design reduces side loading vs any H arm. Covered in the thread below. I remain convinced that it is the best design out there (that I've seen anyway) and I was happy to help Apex with the design.

As to the camber issue, you should be adjusting that with plates on top IMO. We have all seen the photos of the guys with the rod ends turned way out to add camber, but it's really not a good idea. Been a while since I did the math, but from memory I believe the engineering rule of thumb is 2x the diameter should be in the arm, which on a 5/8" rod end means you can move it out something like 5/16" before you hit that limit.

 

Edited by JMortensen

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@Mike Mileski I agree, I mean my alignment guy said about as much, but once he set it, that was it. I have no real thoughts of changing it anytime in the future. I did ask if it was extra, but he said all their race alignments are the same price regardless of how much or how little is adjustable.

 

Probably not a big deal in design to add a bigger rod end adapter and a small piece to space it out like TTT.

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