Floating / Dynamic Center Hub Cap V2 (parametric with OpenSCAD)

Last update: 2025-03-13

Version 2:

• Changed top cap connector to use m3 screws
• Fixed clearance issues
• Improved printability of swing
• Added generic tester

Older releases: https://github.com/Bob-vdV/floating-hub-cap/releases 

Floating center cap where the logo stays upright as the wheel turns. It uses M4 screws as weights. It is originally designed for a 65mm center cap, but the diameter can be changed easily using openscad.  The most important measurements for generating custom sizes are given in the last image. Feel free to ask for any other cap diameter. 

All openscad files can be downloaded on Github at https://github.com/Bob-vdV/floating-hub-cap (Code → Download ZIP) and the STL files can also be downloaded at https://github.com/Bob-vdV/floating-hub-cap/releases/latest. Custom caps can be made easily using black&white SVG's or by combining the plain cap with custom models. Alternatively, a metallic vinyl sticker could be applied on the plain cap. 

Printing

Print with a heat- and UV-resistant material (PETG, ASA, …)

Standard settings are okay for most parts. Supports are only necessary for the top covers in specific orientations and the tester.

Print one base, swing and top for each wheel. 

For the flat top cover, the logo can be printed in a different color using a filament change. For a good surface finish I recommend using hilbert curves as top infill.

Assembling

For assembly of 4 floating hub caps you need:

• 4x 608 bearings
• 20x M4 10mm screws
• 20x or 40x M4 nuts 
• 4x M3 6mm screws

You can choose the number of nuts depending on the quality of the bearings and maximum speed, where higher speeds require more nuts (weight). Theoretical maximum speed calculation is described in the testing section below.

The bearing is press-fit into the base. The top cap can be connected to the swing using an m3 screw 

Testing

The maximum speed can be determined with the hubcap tester and a drill. Film it with a slow-motion camera when it is stable to get the max rotations per second and use the following formula:

max_speed (km/h) = tire_diam (m) x π x 3.6 x rotations_per_sec

In my case with 40x nuts, 64cm tires and 40 rps this gives 290 km/h.

Using only 20x nuts it can rotate at 24 rps, which gives 170 km/h maximum. 

Share it!

I would love to see other people's results, so please post a make or create your own top cover design.

A like is also appreciated!

Redesigned from scratch as modular parametric version with swappable top covers and M4 screws for weights.