7
Audi TT (8S) Control Arms
- Thread starter jdlavelle1975
- Start date
MrFabulous
Ready to race!
- Location
- Chicago, IL
- Car(s)
- 2017 GTi Sport
YWWV, I hesitate to go this route because now you've altered the load path. Rather than transferring the load to the control arm under compression and only using the hardware for locating the joint, you're asking the hardware to take the load under compression. Something it wasn't designed for. You may be able to get away with it in a short term, but I'd be checking that hardware before and after every event (since your avatar indicates you've been on track). There may also be a change in roll center, but that's also based on ride height.
I do like the other solution of slimming down the pad on the control arm. That is a good alternative.
I'm confused as to what's going on here. The normal position is to have the ball joint on top of the LCA. You're right in that flipping it would be a bad idea, but q74 seems to be describing the standard orientation?
Normal for golfs/a3s but for tts it's the other way around. Here's a press diagram to prove it. Note the spindle shape as it provides a ton of clearance around the ball joint.
I followed in @MrFabulous footsteps today and took a couple mm of spindle off from around the ball joint retaining plate and now all is well. I think this is the only way to do it (my suggestion of filing a bit of the control arm itself wouldn't work since the retaining plate is the bit that makes contact/slices into the spindle). For anyone looking to do the same, a set of bits similar to these and a dremel is all you need.
MrFabulous
Ready to race!
- Location
- Chicago, IL
- Car(s)
- 2017 GTi Sport
A3/GTI is a steel control arm and a ball joint designed to go with it. That ball joint mounts to the top of the control arm. The TT is an aluminum control arm with adjustment for camber, with a ball joint designed for it that mounts to the bottom of the control arm and had a bit of a tooth engagement to prevent alignment slippage. I'm not saying it's "wrong" I'm just saying I personally hesitate to flip the mount for the aluminum arm. I also hesitated to clearance my CSS spindles to comply with the ball joint but I was more comfortable with that adjustment than flipping the ball joint. The material removed may have an effect on the amount of side load the spindle can receive without failure, but I feel like if you take a side hit to the wheel at the amount required to break the spindle you're going to have other problems.
Keep in mind the clearance issue is only for the aluminum control arm. I and others had upgraded to the aluminum control arms for the camber benefit. If you plan to use only the CSS spindles with the standard GTI steel control arms, you will have no interference issues.
Sometimes in order to get what we want we have to make choices to accomplish the task. Flipping the ball joint on the aluminum control arm may work just fine, but I personally would check the bolts regularly.
Keep in mind the clearance issue is only for the aluminum control arm. I and others had upgraded to the aluminum control arms for the camber benefit. If you plan to use only the CSS spindles with the standard GTI steel control arms, you will have no interference issues.
Sometimes in order to get what we want we have to make choices to accomplish the task. Flipping the ball joint on the aluminum control arm may work just fine, but I personally would check the bolts regularly.
Gotcha, pulled up my TT service manual and it looks like the ball joint is below the arm and the locking plate is on top. Whereas my whiteline BJ is locking plate, BJ, then arm. I dunno why having it on top of the LCA would be an issue if it fits. Just screws with your geometry.
DerHase
Autocross Champion
- Location
- Hampton Roads, VA
- Car(s)
- 2019 GTI Rabbit
Changing the ball joint and arm with each other won't affect anything load wise or geometry wise.
The load transfer from the road to the upper strut still goes from center of hub upwards to the knuckle. The control arm and lower ball joint literally just locate it laterally. That's why they can get away with super thin stamped LCAs in the first place... there is no appreciable vertical loading on them. It's not a double a-arm car where the strut pushes downward on the LCA which pushes downward on the ball joint pulling downward on the knuckle.
It goes from the strut directly into the knuckle/hub on a Macpherson strut style suspension like this.
Geometry is unaffected as well because the center of the ball joint in relation to the knuckle is all that affects anything roll center or SAI-wise etc. You could make a lower control arm that does a loopty-loop and it wouldn't change anything (aside from additional flex under lateral loading).
The only thing that WILL be affected is where the ball joint sits within it's usable range of motion (ROM).
If you put a ton of angle on the LBJ at ride height, there's a possibility it'll use all of it's ROM at full droop, or full bump, etc. Best way to know for sure would be the remove your spring and reinstall the rest of the suspension like normal and cycle it all the way up and down while turning full lock each way etc to check for binding.
Alternatively in reality - if you have shorter than OEM shocks or short travel coilovers (basically everything out there), then putting the ball joint on top vs below will only eat up downward (droop) travel anyway and it won't matter.
Someone can put an angle finder on the lower ball joint (or arm below where it's mounted if LBJ is on top) to see the difference. I'd bet it's less than a 1.5 degree difference in angle.
The load transfer from the road to the upper strut still goes from center of hub upwards to the knuckle. The control arm and lower ball joint literally just locate it laterally. That's why they can get away with super thin stamped LCAs in the first place... there is no appreciable vertical loading on them. It's not a double a-arm car where the strut pushes downward on the LCA which pushes downward on the ball joint pulling downward on the knuckle.
It goes from the strut directly into the knuckle/hub on a Macpherson strut style suspension like this.
Geometry is unaffected as well because the center of the ball joint in relation to the knuckle is all that affects anything roll center or SAI-wise etc. You could make a lower control arm that does a loopty-loop and it wouldn't change anything (aside from additional flex under lateral loading).
The only thing that WILL be affected is where the ball joint sits within it's usable range of motion (ROM).
If you put a ton of angle on the LBJ at ride height, there's a possibility it'll use all of it's ROM at full droop, or full bump, etc. Best way to know for sure would be the remove your spring and reinstall the rest of the suspension like normal and cycle it all the way up and down while turning full lock each way etc to check for binding.
Alternatively in reality - if you have shorter than OEM shocks or short travel coilovers (basically everything out there), then putting the ball joint on top vs below will only eat up downward (droop) travel anyway and it won't matter.
Someone can put an angle finder on the lower ball joint (or arm below where it's mounted if LBJ is on top) to see the difference. I'd bet it's less than a 1.5 degree difference in angle.
Got my alignment done properly, looking fwd to the first track day in a couple months to see how it feels. What do you guys recommend for toe? Large circuits, no autocross. Also don't want my tires wearing down too quick if it makes a big difference. TIA
DerHase
Autocross Champion
- Location
- Hampton Roads, VA
- Car(s)
- 2019 GTI Rabbit
Zero toe is what I run. No complaints.
Swapped to 8Y LCAs and listed my 8S ones for sale - https://www.golfmk7.com/forums/inde...-lcas-oe-trans-mount-oe-dogbone-mount.423132/
Just ordered from e-acca, took 3 weeks or so
I have all the parts to do the swap but not ready to do it yet. Yes it will increase track width. Hence why I’m going to get wider guards first before doing it. Yes you need the matching outer tie rods. Also takes a different pinch bolt and nut.
I am very interested to see an alignment sheet with all OE audi front parts. I just went back to basically the CSS setup with camber plates, the simplicity sure is nice.
Hi, I would like some info if anyone has done this before.
I would like to install ball joint in LEMFÖRDER I don't know if: 8J0407175 is supplied with.
8J0407365 - right hand
8J0407366 - left hand
but I would like to keep my control arm from my OEM leon cupra 300.
do you know if the ball joints go over it or you have to change the control arms?
I would like to install ball joint in LEMFÖRDER I don't know if: 8J0407175 is supplied with.
8J0407365 - right hand
8J0407366 - left hand
but I would like to keep my control arm from my OEM leon cupra 300.
do you know if the ball joints go over it or you have to change the control arms?