Reconstruction of the BMW E30 wheel covers by 3D printing

A nagging issue that many BMW lovers of the 80s models are familiar with: The hub caps of their original cross-spoke rims have once again fallen into the hands of thieves or the locking mechanism has failed. They are now lying somewhere in the ditch or have been lost.

Either way, replacements are needed, because no true BMW enthusiast likes to see his wheels without the beloved black and blue emblem in the middle.

Since the original BBS hubcaps are only produced in limited quantities, the well-known auction platforms and authorised dealers are now asking prices of more than €350 for a new set.

Rapid prototyping can put an end to this market monopoly. The hubcaps of the original cross spokes of the E34 and E39 models are made of plastic and can be produced entirely by 3D printing or vacuum casting. The plastic covers are also an option for budget-conscious E30 drivers who can make small sacrifices in terms of original fidelity. For those who don’t want to miss the aluminium outer ring on their Styling 5 cover, selective laser melting, or SLS for short, is just the thing. In this process, the component is melted layer by layer from aluminium powder by means of a precise laser insert. The advantage of a new edition of the original part is that you have a free hand in the design and could even integrate a hidden anti-theft mechanism.

The first successful attempts to reproduce the covers for Styling 5 rims completely in the 3D printer were achieved through the cooperation of dedicated members of a BMW E30 forum. First, we created a CAD model based on the original hub cover, which was then divided into 105 individual layers of 0.2mm thickness using special software suitable for the printer. The process took 8 hours and around 30 metres of a particularly impact-resistant ABS filament per piece. Due to the individual layers, a rough surface was created, which was then brought to a smooth finish (surface) with acetone steam. Finally, painted in the original colour and the “homemade” hub cap is finished.

For series production, the same 3D model can be manufactured using selective laser sintering, or SLS for short. The polyamide plastics used here are more robust and weather-resistant. In addition, less reworking is required here. The final product is trowalised and then painted.

Although only a 3D printer was used for home use, the result is almost indistinguishable from the original and gives an idea of what is possible with industrial-standard additive manufacturing processes in series production.

Please also visit our other articles on the subject of 3D printing and reconstruction for vintage and classic cars.