cad drawing for balljoint extenders

[cabby85]

Does anyone have a cad drawing for mk2/mk3 ball-joint extenders I can have my buddy build me some, just need some dimensions.

[zigm89]

This may be a really dumb idea.......but:

Why don't people use a solid piece of metal and relocate the ball joint mount to the top of the control arm? Seems like it would be a lot simpler and stronger ($15 worth of flat metal vs the $200 extenders)

Here is a very crude drawing showing what I'm thinking about:
Yellow blocks would be steel or aluminum and sandwich the balljoint mount. Get some longer bolts, and you can reuse the existing holes in the control arm. Thoughts?

[Maxf31]

It would not correct the suspension geometry.

[gbisus13]

It would not correct the suspension geometry.

Actually, it would.

And you could use the plate to lengthen the control arm as well by drilling a second set of holes further out, the inner set bolts to the control arm, the outer set to the ball joint.

[Light on Fuel]

Actually, it would.

And you could use the plate to lengthen the control arm as well by drilling a second set of holes further out, the inner set bolts to the control arm, the outer set to the ball joint.

I'm pretty sure that he's right. I can't remember where, but I've seen the extenders somewhere on the web for sale. I'm not sure if they were home-made or not because it was a couple of years back.

[meboice]

What would be accomplished by extending the lower control arm length, all else equal? If the lower control arm is parallel with the ground nothing else changes...Camber curve remains the same...instant centers remain the same...other elements do change, what is being corrected?

[Light on Fuel]

What would be accomplished by extending the lower control arm length, all else equal? If the lower control arm is parallel with the ground nothing else changes...Camber curve remains the same...instant centers remain the same...other elements do change, what is being corrected?

It allows for more camber adjustment at the ball joint, which MKIV's currently do not have. Here's the thread. The part is manufactured from Ingalls Engineering, so I'm not sure why a CAD file is needed.

Although, it seems that extending the ball joint further out would also reduce its range of movement. That's one of the reasons that I never really followed up on them. I prefer to try and set the suspension up in a way that makes them unnecessary. OP: Are you interested in making them to use in a motorsport application?

[meboice]

I was thinking about this modification this morning for a bit...I did play around with my drawing for a few minutes and without knowing the actual existing geometry and the change it's hard to see exactly how much camber gain/travel there is. But there may be some serious scrubbing forces at work here too as the suspension moves up and down...and I wonder what the influence is on roll center migration...I'll jump into this more later. Interesting though...not sure I've ever seen a ball joint extension...I've seen plenty altered to correct roll center height but that's in a vertical plane.

[Light on Fuel]

I was thinking about this modification this morning for a bit...I did play around with my drawing for a few minutes and without knowing the actual existing geometry and the change it's hard to see exactly how much camber gain/travel there is. But there may be some serious scrubbing forces at work here too as the suspension moves up and down...and I wonder what the influence is on roll center migration...I'll jump into this more later. Interesting though...not sure I've ever seen a ball joint extension...I've seen plenty altered to correct roll center height but that's in a vertical plane.

I'm still a bit on the fence about it. Since the strut is fixed with a pinch bolt, that extra bit of adjustment means that something somewhere needs to compensate for that. In my thinking, that extra adjustment would mean that the angle of the ball joint, when at rest, would be increased and would therefore reduce its range of motion. I don't know though; it's merely speculation. Do you have that diagram in AutoCAD? If so, would you be able to email it to me?


\X/

[Dturpin]

It would not correct the suspension geometry.

What he said. Putting a spacer below the balljoint will only change the angle of the control arm. Its the virtual line between the balljoint pivot point and the inner control arm pivot point that matters

[zak]

What he said. Putting a spacer below the balljoint will only change the angle of the control arm. Its the virtual line between the balljoint pivot point and the inner control arm pivot point that matters

This.

You need to lower where the balljoint connects to the spindle/steering knuckle. On MkII & III Golf and Jettas, you can use a ball joint spacer. Someone in Colorado makes them; a search of this forum will find them.

For the MkIV Golf and Jetta, the angle of the balljoint precludes using extenders, so you need to get spindles with lower attachment points for the balljoints, such as the Audi TT spindles or drop spindles produced by some Canadian company (again I forget the name, but search reveals all).

[meboice]

I was thinking about how in a daze my response above was...I still don't know what the OP is correcting or trying to change. But, moving the upper ball in or out relative to the car's centerline on an SLA design alters camber. Of course, altering camber also alters SAI.

Extending the lower ball joint on a MacStrut will increase negative camber, but it also places the strut mount in an odd position...assuming there is a stock strut mount in place. If there is a spherical bearing then all is well.

I'm on vacation and a bit buzzed so I'll not add anymore for now

[20v master]

There is a Mk1 TT user who has these types of plates. The purpose isn't to alter the control arm geometry. It's to add static negative camber as well as increase caster.

[meboice]

If the lower control arm is perfectly horizontal then static lower control arm geometry has not changed. If the lower control arm is at some angle, then adding to its length changes its angle...perhaps immeasurable within the context of actual driving...but it does change within the pure context of geometry.

What this actual does depends upon the length of the control arm, the SAI angle, distance between the upper strut and lower ball joint.

I imagine, as I wrote above, that altering the lower control arm as a way of altering static camber might place some unwanted thrust load on a stock strut bearing...perhaps this is meaningless as well.

How does this part alter caster? I don't see, in side view, how the caster angle can be changed unless the ball joint pick-up point is offset. This isn't apparent in the photo.

I'm not knocking this modification, just pointing out a few things I see...might be a lot more that I don't see.