With 37's and approx 6 inches of lift there is NO WAY my factory control arms could match the correct driveline angles.
Brent,
First off. The AEV fit runs 4.5" to fit 37s and the angles allow for use of the stock shafts. If you are at 6" you would be outside the use of this supension anyway, so what's the point?
Now, if you upgrade drive shaft later and have the AEV kit you may want adjustable uppers to get pinion correct.
Also I am able to re-center my rear wheel in the wheel well. Put a lot of lift on A JK with factory arms and it will look like your rear wheels are about to jump into the back seat.
Second, I asked Jim at AEV about this. He pointed out that a centered wheel in the wheel well at rest does not match up with the wheel well and bumpstop at full compression.
He said they are supposed to be offset, front tires should be rear of center and rear should be front of center. That way at full stuff they land center and hit their bumpstops. Which would be very important for any high speed desert driving, hitting big dips and rock crawling stuff.
I can see where people want it to look centered, but how does it REALLY fit at full stuff? Maybe this is why you are at 6" of lift to fit 37s, and the AEV does 4.5" to fit the same tire?
As far as the TF lift "hanging at speed in the corners" I am kind of curious what specific geometry difference will cause the TF to under perform? I really don't drive my Jeep like a sports car so I guess I can't comment from personal experience. .
Someone, I think it was "Chuck45" had talked to Jim about his specifically and made a post about it. I was trying to find his post but can't seem to. (can't remember what forum or thread specifically he posted in on)
I will see if I can get the basics correct.
When the Jeep is lifted the COG moves up. Creating a much larger lever arm on the roll center of the vehicle, so changes need to be made to correct for this.
AEV recalculated where the Roll Center should be on the Jeep and not simply just fabricating components to compensate for lift height. Take a look at their (I will post a picture later) rear track bar location. It is not just a 4.5" raise to correct for the lift. It is over an 8" raise to put the roll center where it should be for proper stability.
My understanding is that the way Tera corrects for the track bar with a drop bracket, and by not moving it far enough they are actually lowering the roll center, which in turn actually makes the jeep more prone to rolling over than less.
The next part is how this all ties into the steering and roll center. The AEV set up takes into account things like "roll steer", "Roll over-steer", "Roll under-steer", etc and not just "bump steer". At this point most have figured out that the drag link and track bar should be parallel. According to Jim at AEV, they also need to exist in the same "plane" and that the functional intersection point (since they are offset to each other) needs to be at the roll center of the Jeep. (remember the rear roll center part from above?)
This is just the geometry correction stuff. Talking to Jim at AEV about their springs is a whole new story. I will try to put some info together on it later.
Basicly the rear of the Jeep needs to respond in time with the front designed around a specific speed. So that it is within that spec for a given speed range. This is what gives the Jeep it's stability at speed and why the AEV stuff does so well going fast on dirt roads(and the street).
There is simply no way that a 4 door spring set can be used on a 2 door and get the expected handling results. So I would beware of any company with the same part# for 2 and 4 door modles. (ever driven a Jeep that wants to dribble sideways on a washboard road? The AEV set up just flys on the stuff with none of that effect because the springs are responding as a tuned set).