[vtl]

This is a ball joint upgrade for the rear control arms which replaces the factory rubber bushes. Replacing the rubber joints with ball joints will provide a much more stable rear end, and is a must if you're particular with how the car handles. For high hp cars, these are a must to keep the car pointing straight under power.

The reason for this group buy is because these Lemforder ball joints are hard to get now in quantity (FCP don't sell them) and might actually be no longer available soon. Stuff like Meyle is easily available but personally have found their parts to be junk.

For this group buy, you get a total of 8 ball joints:

2 for the guide rods
2 for the upper control arm
4 for the trailing arm

This upgrade assumes you already have M3 rear control arms (the guide rod and upper control arms)

For example this:
https://www.fcpeuro.com/products/bmw...-e93-bmwmcaktr

The sealed Lemforder ball joints I am sourcing are high quality items that will last well over 200,000kms easily, unlike the aftermarket unsealed joints that will likely knock after several thousand kms. I have tested the joints and they press nicely into the M3 arms.

The trailing arm joints are located in the knuckle and subframe, these joints also happen to be the same size and are a good fit.

I did a group buy last month for these and ended up being around $326 AUD delivered for 8 ball joints. Final cost will depend on current exchange rate

Additionally the upper control arms require a tapered adapter for these joints, which we will get CNC machined in stainless steel. I can also help out with installation of the joints in Melbourne, or you can post your control arms to me.

There's only 4 spots available per round (to avoid customs charges). I'm capping this to 4 rounds. Once there's enough people for a round it goes ahead

Ball park figure for the group buy is $326 AUD delivered, prices change slightly +-$10 depending on the conversion

Round #1

1. Phil Rybinski
2. Stuart Lord
3. Jin Zhou
4. Jin Zhou

Round #2

1. Joseph Foti
2. Peter Agas
3. Grant Mitchell
4. Jin Zhou

Round #3

1. Brendan Trickett
2. Vin Wayne Kerr
3. Alex Wong

Round #4

1. Geoff Brothers
2. Brian Izadfar
3. Calvin Chau

Located Melbourne, if you're interstate can still join in as long as you cover postage.

[vtl]

For some reason pictures didnt upload on the initial post, fixed!

[vtl]

Rounds 1,2 and 3 have been ordered, just need 1 more person for round 4!

[vtl]

Group buy closed! Thanks everyone for participating

[vtl]

Just adding this in for posterity

For more information on the engineering of these parts look here (may need to scroll back a few pages):

https://www.1addicts.com/forums/show...7#post25231637

We ended up getting 17 people in total for the monoball group buy, which was a great result. Got the CNC'd washers at the end of last week and they turned out fantastic. The washers were made to the design specs out of stainless steel, so will be strong and resistant to corrosion.

Due to the fact that the thickness of the washer would change the geometry of the suspension slightly, I have calculated that the joints must be installed 3mm offset to maintain the factory geometry. This is fairly easy with a hydraulic press and using a pair of digital calipers.

Very happy with how this project turned out, just need to get these things installed!

Big thanks to everyone who participated!

[Socket]

Great work Vince. These turned out mint

[vtl]

First install on Socket 's car

I ended up dropping the subframe around 30-40cm from the body. This enabled me to remove the arms easily and torque them up. This also allows easier access to the trailing arm bushes which are quite close to the fuel tank.

The tools would simply not fit until the subframe was lowered enough out of the way. it may be possible to cut down and machine my tools to fit in that tight spot in future installs.

The trailing arm bushes also didn't start straight, and I decided to file down a slight lead in chamfer to aid installation. This made them start flawlessly every time, and worked very well.

[vtl]

Some pictures of the trailing arms

These are a bit tricky to get installed without the correct bushing cup tools that will fit in the area. The knuckle side required me to remove the brake disc. On further installs I will cut down the bushing tools to fit in the area so parts do not need to be removed.

Driving impressions:

I've only done a short test drive but suprisingly has made a noticeable difference. Socket's car already has the M3 guide rod and hardrace toe arms so this upgrade has given 4 extra ball joints. The rear end feels much more stable and doesn't have any of the characteristic e8x/e9x rear end wobbliness. Addtionally, the rear suspension feels better damped, as the rubber bushes aren't constantly winding up and resisting the motion of the arms. I believe the rear shocks are unable to dampen the rubber windup effectively.

[Socket]

Great work Vince (as always) can’t wait to take Gary out for a spin on sone twisties and experience the improvements for myself. Makes me wish I’d gone with the solid bushings now but this sounds like a big improvement as it is 👍

[alindquist]

Originally Posted by vtl

Some pictures of the trailing arms

These are a bit tricky to get installed without the correct bushing cup tools that will fit in the area. The knuckle side required me to remove the brake disc. On further installs I will cut down the bushing tools to fit in the area so parts do not need to be removed.

Driving impressions:

I've only done a short test drive but suprisingly has made a noticeable difference. Socket's car already has the M3 guide rod and hardrace toe arms so this upgrade has given 4 extra ball joints. The rear end feels much more stable and doesn't have any of the characteristic e8x/e9x rear end wobbliness. Addtionally, the rear suspension feels better damped, as the rubber bushes aren't constantly winding up and resisting the motion of the arms. I believe the rear shocks are unable to dampen the rubber windup effectively.

Hey! Do you might have som washers in spare? Interested in 4 pcs.

[regbf99]

Hey Guys,
are there some long-term experiences about this upgrade?
Maybe even from race track driver?

[TommyNgu]

Originally Posted by vtl

Just adding this in for posterity

For more information on the engineering of these parts look here (may need to scroll back a few pages):

https://www.1addicts.com/forums/show...7#post25231637

We ended up getting 17 people in total for the monoball group buy, which was a great result. Got the CNC'd washers at the end of last week and they turned out fantastic. The washers were made to the design specs out of stainless steel, so will be strong and resistant to corrosion.

Due to the fact that the thickness of the washer would change the geometry of the suspension slightly, I have calculated that the joints must be installed 3mm offset to maintain the factory geometry. This is fairly easy with a hydraulic press and using a pair of digital calipers.

Very happy with how this project turned out, just need to get these things installed!

Big thanks to everyone who participated!

Are you still selling these CNC adapters?