SPF Front Hub Retention Ring Failure

Hi James,
I don't understand how that tang works.
Is it something that gets inserted after the wheel nut is torqued to spec and then bolted on to prevent the nut backing off?
If so, then the wheel nut never actually reaches a point where the threads are stretched to a point where it is an interference fit.

Is the tab/tang the only thing stopping the wheel nut from working loose?

regards Ryan
 
Hi James,
I don't understand how that tang works.
Is it something that gets inserted after the wheel nut is torqued to spec and then bolted on to prevent the nut backing off?
If so, then the wheel nut never actually reaches a point where the threads are stretched to a point where it is an interference fit.

Is the tab/tang the only thing stopping the wheel nut from working loose?

regards Ryan
Yes the retention ring is placed after the bearings are set to keep the nut from coming loose. Yes the ring with the tang is the only safety keeping the nut from loosening.
 

Markus

SPRF40
Lifetime Supporter
Here are pics from other threads which deals with that design...


There are several threads regarding SPF wheel bearing issues.
 
Here are pics from other threads which deals with that design...


There are several threads regarding SPF wheel bearing issues.
Thanks for the link. One of the reasons why I'm doing videos is to help minimize sorting through the facts on the forums at times
Pat
 
Because SPF exactly copies the original parts 2 tapered roller bearings are used. There is no way to get an interference fit. More modern bearings like double row angular contact ball bearings are used on most race cars now. That being said I've owned my SPF for 14 years now and have not had this problem occur despite multiple removals and adjustments. Will inspect that tang carefully in the future.
 
back in about 2000, I hade a chance to look over an Audi R8 LMP car front suspension knuckle/upright. This used a similar live axle set up with the bearings retained in the upright and the hub/axle component spinning within the ID of the bearings.

The center lock hub went in from the outside and was secured with a large nut (approximately 4” ID), just like the arrangement that Superformance use.

However to retain this nut, slits were machined into the flat faces on the outside and a small cap head screw was installed parallel to the axle axis. These screws then compress/deform the thread in the nut resulting in the sufficient interference to prevent the axle nut loosening off.

I have been told that Porsche may have also done similar on maybe the 928. I'm yet to confirm this.
 
The Olthaff Racing upgrade as well as the other side retention ring which also failed. In my opinion these should be inspected on all SPF front hub assemblies. The Olthaff upgrade is a higher quality material and refined. I recommend highly. Olthaff guys have been more than helpful.
 

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