Rose/Heim Joint Longevity
#16
Addict
Rennlist Member
Rennlist Member
I think they’re the same type of joints as in GT3, but RS uses them in additional place(s) where GT3 still uses a rubber bushing.
#17
Drifting
Thread Starter
Ah. Ok, so that makes sense now. Thank you for the clarification. So RS has mostly ball joints. GT3 has mostly rubber bushings. And somewhere along the line people confused ball joints with rose joints. So the answer to my original question is "don't worry about it lol."
#19
Drifting
Thread Starter
That's why I was asking about rose joints. They're even worse on the road. But since the RS doesn't have them, it's a non-issue.
#20
Ah. Ok, so that makes sense now. Thank you for the clarification. So RS has mostly ball joints. GT3 has mostly rubber bushings. And somewhere along the line people confused ball joints with rose joints. So the answer to my original question is "don't worry about it lol."
_____________________
991.2 3RS
E92 M3 Tarmac Rally
F56 JCW
#21
Drifting
Thread Starter
Great, thanks!
#22
Three Wheelin'
While it is technically correct to refer to the joints used by Porsche for the RS suspension (and in a portion of the GT3 suspension) as ball joints, they are not ball joints in the traditional American auto manufacturer manner.
Traditional automotive ball joints have a ball or sphere at one end and a tapered shaft extending from the ball to a straight threaded end and are typically found at the ends of the front spindle upright. Normally the ball and housing is pressed into the spindle. The side of the ball away from the tapered shaft has a metal cover and there is a rubber boot on the side with the tapered shaft.
The Porsche joints are similar to bearings used by other European auto manufacturers (I've specifically seen them on BMW rear trailing arms where the upper and lower control arm connects from the diff housing to the trailing arm. Effectively they are a greased, double shear spherical joint with dust boots on both sides.
Heim and Rose joints are better defined as rod end bearings - they are designed to provide both a low tolerance spherical bearing for movement and length adjustment of the specific suspension member to which they are attached. The length adjustment may be designed for manufacturing and assembly or for end user tuning depending on the specific application.
IMHO Porsche selected durable, quiet components similar to those used in their competition cars. They didn't need to select rod ends as the adjustment in the suspension is accomplished by other means.
Ryan
Traditional automotive ball joints have a ball or sphere at one end and a tapered shaft extending from the ball to a straight threaded end and are typically found at the ends of the front spindle upright. Normally the ball and housing is pressed into the spindle. The side of the ball away from the tapered shaft has a metal cover and there is a rubber boot on the side with the tapered shaft.
The Porsche joints are similar to bearings used by other European auto manufacturers (I've specifically seen them on BMW rear trailing arms where the upper and lower control arm connects from the diff housing to the trailing arm. Effectively they are a greased, double shear spherical joint with dust boots on both sides.
Heim and Rose joints are better defined as rod end bearings - they are designed to provide both a low tolerance spherical bearing for movement and length adjustment of the specific suspension member to which they are attached. The length adjustment may be designed for manufacturing and assembly or for end user tuning depending on the specific application.
IMHO Porsche selected durable, quiet components similar to those used in their competition cars. They didn't need to select rod ends as the adjustment in the suspension is accomplished by other means.
Ryan
#23
Rose joints, heim joints, rod end bearings, and ball joints, are all common terms for a Spherical Bearing. Rose joint and heim joint are effectively interchangeable and genericized brand names for spherical bearings. Spherical bearings can be either: male, with the stud integrated into the sperical portion; or female, with the spherical portion having a bore extending therethrough.
A vehicle's "ball-joints" (which are more or less universally used to connect control arms to the wheel hub) are a type of spherical bearing. They are frequently male with a tapered shaft and are retained to the wheel hub with a nut threaded on the shaft, and typically do not have any compliance, between the spherical portion and the race (unless they're worn, and should be replaced). They are usually sealed with a rubber bellows type boot.
Rubber bushings, as the name suggests, have rubber in them, and permit movement between the inner and outer portion similar to that of a spherical bearing, while also damping NVH. On race cars and cars Porsche has deemed worthy, some or all of these rubber bushings may be replaced with spherical bearings for the benefit of handling.
Marketing depts. will take creative license with the advantageous removal of rubber bushings and will use any of the aforementioned terms (rose, ball, heim, etc) interchangeably, as dictated by regional customs, intended audience, and/or without regard.
Now that we've cleared up bearings, regarding the OP's original questions specific to the RS, I have no personal experience.
A vehicle's "ball-joints" (which are more or less universally used to connect control arms to the wheel hub) are a type of spherical bearing. They are frequently male with a tapered shaft and are retained to the wheel hub with a nut threaded on the shaft, and typically do not have any compliance, between the spherical portion and the race (unless they're worn, and should be replaced). They are usually sealed with a rubber bellows type boot.
Rubber bushings, as the name suggests, have rubber in them, and permit movement between the inner and outer portion similar to that of a spherical bearing, while also damping NVH. On race cars and cars Porsche has deemed worthy, some or all of these rubber bushings may be replaced with spherical bearings for the benefit of handling.
Marketing depts. will take creative license with the advantageous removal of rubber bushings and will use any of the aforementioned terms (rose, ball, heim, etc) interchangeably, as dictated by regional customs, intended audience, and/or without regard.
Now that we've cleared up bearings, regarding the OP's original questions specific to the RS, I have no personal experience.
Last edited by BillNye; 03-21-2019 at 09:06 AM.
The following 2 users liked this post by BillNye:
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#24
Drifting
Thread Starter
Rod-end bearing/Heim/Rose joint vs ball joint vs bushing.
#25
Just to be accurate, the GT3 has slightly more ball joints than rubber bushes, but I can't remember the exact number. The RS has no rubber bushes except for the anti-roll/sway bar rubber bushes. And yes, nothing to worry about regarding premature wear.
_____________________
991.2 3RS
E92 M3 Tarmac Rally
F56 JCW
_____________________
991.2 3RS
E92 M3 Tarmac Rally
F56 JCW
#26
Racer
Don’t see why the factory joints shouldn’t last a pretty long time given that high quality Tarett spherical bushings installed in Porsches and BMWs have lasted for north of 30,000 street miles with zero issues. Street miles are more punishing as any jolt to the suspension via bumps or potholes are what causes the wear.
#27
Right, the pictures are the proof. So why do the tech specs for the RS say "all suspension mounts ball-joined" whereas the GT3 does not? And what does Porsche mean when they say, "all suspension joints have been REPLACED with ball joints" in the RS models? What are they in the GT3 models?
#28
Resurrecting this thread, my 2016 GT3RS front control arm outer spherical bearing has failed with approx 1-2mm of vertical play. Porsche only sells the complete control arm. Does anyone know if the piece can be purchased separately?
#29
Any details on the car please, eg mileage on road and track, tire selection
#30