1969-1975.5 Rear Wheel Bearing, Hub and Stub Axles

[Captain Ahab Jr]

Hopefully someone will know this or have a few parts lying around that can do a quick measure up for me please.

I'm trying to mix and match various Porsche parts to use with a custom machined rear suspension upright to end up with a combination of wheel bearing, wheel hub and wheel stub axle that will give a 94mm CV joint PCD to match the 930 CV joints I want to use.

At the moment I have early 928S wheel bearing, wheel hub and stub axle which will do the job but I pretty sure using early 1969-1975.5 MY 911 parts might be a lighter weight route to go down but before buying more parts I need to know,

What are the wheel bearing dimensions, OD, ID and length?

What is the weight of the wheel hub?

I think the stub axle bolt PCD 94mm but what size are the four threaded holes, M8 or M10 and what diameter are the two dowel holes?

Thanks,

[Flieger]

What is PCD?

[Captain Ahab Jr]

PCD is the pitch circle diameter, ie the diameter the threaded bolt hole centres are positioned on

[ivangene]

hmmm...
OT

PCD? I always called it BCD (bolt circle) never heard a bolt circle use the term pitch...

[Captain Ahab Jr]

BCD or PCD, same thing depends what side of the pond you live

I googled PCD to check I wasn't making it up and the first few search answers was the Pussy Cat Dolls, much more interesting

Back on topic, can anyone help me out here??

[Grady Clay]

The CV joints are described by their outside diameter (OD).
The two we are discussing here are 100 mm and 108 mm Lobro CV joints.
If you are considering using the late 108 mm versions common to 911 Carrera and 930 Turbo, they use six M10 bolts.
The later versions also have a tin end cap and don’t require a gasket.
The transmission axle flange and the stub axle for these are configured to not use a gasket.
The later version of the stub axle uses an M22x1.5 steel lock nut in place of the earlier M20x1.5 castle nut and cotter pin.

You will find several earlier versions of these 108 mm CV joint stub axles with four M10 bolts and two 10 mm roll pins all with the earlier 20 mm threads on the stub axle.
All these earlier stub axles require a gasket to the CV joint, some earlier with the gasket outside the bolt circle and some later inside.

The 4-point wheel bearing became significantly larger in ’74. The OD and axial thickness increased but the ID for the stub axle and hub remained the same.


If you are considering very-high-load racing use, the 930 Turbo uses a completely different and far more rugged system.
In place of the single 4-point bearing, there are two large and wide-spaced tapered roller bearings.
Everything else is different also; hub, stub axle, etc. and the axle shaft (between the two 6-bolt, 108 mm CV joints) is much shorter to accommodate the wider spaced bearings.

Don’t even consider using the 100 mm CV joints unless you are sub-1500# car and less than 100 hp.
These were suitable for the 2.0 923 (’76 912E) but undersize for the 3.0 911SC.

Best,
Grady

[Flieger]

Originally Posted by Captain Ahab Jr

BCD or PCD, same thing depends what side of the pond you live

I googled PCD to check I wasn't making it up and the first few search answers was the Pussy Cat Dolls, much more interesting

Back on topic, can anyone help me out here??

Interesting. Never heard that term here. Just bolt circle.

[ivangene]

when I get home I am going to google PCD

[Nine9six]

Over here Capt, pitch is usually a term used to describe a measurement dimension over threads or spline.

PCD stands for pitch circle diameter and is the diameter of a circle drawn through the centre of your wheel's bolt holes. P.C.D. is measured in millimeters...

[Captain Ahab Jr]

Thank you Grady, excellent info. as always

I will use 108mm Lobro CV joint with M10 holes due to engine power and a large driveshaft running angle.

What are the differences with the versions of the 108mm CV joint stub axles, is it just the gasket detail and is one version lighter than the others?

Do you know what the outer diameter of the pre-73 bearing is? I will leave enough wall thickness in case I need a plan B and have to run the larger bearing.