Rear Upright Failure Update

Update on “Rear Upright Failures on a Birkin S3 IRS Model”!               

Further to the news bulletin dated 08/03/07, Birkin SA and Birkin Sportscars Australia have conducted extensive investigations into the failures of uprights on a PRB supplied IRS car while also reviewing performance of the uprights in a number of other Birkin S3’s, both in Australia and South Africa.  The summary of these investigations is:

• The failure of the uprights on the PRB supplied car are unique and have not occurred on any other vehicle currently running these components under normal road usage.  Further investigations have revealed that this particular vehicle was involved in a rear end collision that may have had some effect on the performance of the uprights.  PRB did not initially advise us of this fact or that both uprights had been repaired and/or had been strengthened by welding, with no appropriate heat treatment.  This car has subsequently been fitted with new uprights and will continue to be monitored as it is being raced.  The old uprights have been returned to SA for further metallurgical testing which may prove meaningless because of there modification by PRB.
•  In Australia, we have swapped out a set of uprights on a car that has accumulated approximately 3000 km of road mileage and crack tested the components with a nil result.
•  In South Africa, uprights have been swapped out of four race cars and crack tested, again with a nil result.
• The Birkin SA race car is a 300 HP machine with 10” slicks.  This car has been aggressively raced for a season and periodic crack testing of uprights has again presented a nil result.  The race car has broken an upright after severe impact with a track kerb which presented loadings well beyond the design brief for the component.

Birkin SA is strongly of the view that the uprights as supplied are more than adequate for intended road usage.  They were designed using FEA to maximise strength while minimising weight.  However, owners are reminded that components cannot be warranted for race usage because of the extreme and unknown nature of the loads that may occur.

Bearing in mind the critical nature of these components, Birkin SA has produced a heavy duty upgrade for the uprights.  This consists of a steel plate which is bolted to the bottom horizontal flange of the upright, while securing the main ball joint.  This component is being fitted as standard to all new uprights and will be provided free of charge to existing owners where required.  The fitting of these plates requires machining of the existing uprights which must be undertaken by Meridian Motorsport for a fixed fee of $290 inc GST, plus shipping.  Uprights will be provided on an exchange basis.