SRAM loses aero wheel patent case against Princeton Carbon Works

Princeton Carbon Works has prevailed after a two-week trial in which the US brand had been accused by SRAM of infringement on two of its patents relating to the design of the Zipp 454 NSW wheels. 

According to Bicycle Retailer and Industry News (opens in new tab), the recent court case concluded with a jury returning a verdict finding that Princeton had not infringed on any patents and was not due any damages.

SRAM/Zipp’s sawtooth profile was designed by celebrated engineer Dimitris Katsanis - whose UK-based company Metron most recently 3D printed Filippo Ganna’s Hour Record Pinarello frame - using the ‘emerging science of biomimicry’ and was said to be based on humpback whales. 

Even though the Princeton rim design has symmetrical ‘humps’ rather than a sawtooth profile and is claimed to have been four years in development, SRAM wanted damages for wilful infringement and for Princeton to be ordered to deliver up for destruction any remaining inventory.

SRAM’s wheels relied on two patents from Katsanis. The first patent was issued in 2017 and a related patent was issued in 2020. Katsanis assigned each to Metron IP Limited, a company based in Nottingham, which in turn then assigned them to SRAM.

In January, Judge Roy Altman  granted some wins and losses to both sides in the case. Altman granted SRAM’s request to put a stop to one of Princeton’s possible defences: a so-called Section 112. This was based on showing that the language of a patent is inadequate to define its scope. 

Altman said that in pre-trial responses Princeton had failed to address Section 112 and had thus waived that potential defence - which meant a partial win for SRAM.

Next Altman said that Princeton could continue a defence that asserted that SRAM’s patent was invalid because of prior art. “We think a reasonable jury could side with Princeton,” Altman said - which was equal to a partial win for Princeton at the time. 

Unbranded Princeton wheels were spotted being used by Ineos in the 2020 Tour de France whereas Movistar are using Zipp wheels in WorldTour races this year.