SRAM loses patent battle with Fox over X-Sync chainring

Latest ruling expected to end six-year dispute over tooth technology that cost both companies millions

SRAM Fox X-Sync

A ruling by the US Patent and Trademark Office has gone against SRAM, after Fox Factory challenged patent claims relating to SRAM’s X-Sync chainring design.

As reported by Bicycle Retailer and Cycling Industry News, the battle dates back to 2015 when SRAM and RaceFace (now owned by Fox) first locked horns over the chain-retaining features of the X-Sync chainring that was designed to be used in a 1x set-up with no front derailleur. SRAM had licensed the wide/narrow tooth design with inboard offset teeth to other brands including Accell and Chromag, but when RaceFace launched its own design, SRAM sued, believing its fellow US brand was infringing its patents.

The US Patent documentation is here.

SRAM Force

SRAM launched 1x X-Sync chainrings for the road in 2015

The US Patent Office was asked by Fox in 2017 to review the patents, and although the patents were upheld, the appeals board noted that SRAM's patent claims combined features from earlier drawings, including some unpatented Shimano technology from the 1980s. However, it upheld the patents partly because the technology was not "obvious", it said, and therefore was patentable. SRAM had also pointed to the commercial success of the X-Sync design.

Meanwhile Fox argued that the commercial success of the X-Sync chainring was not due to the patented technology but rather due to the fact that it was paired with a wide-ratio cassette, asserting that it was therefore not tied to the patent.

A further appeal agreed with Fox, finding, in US law firm Finnegan's words, that "the secondary considerations were not properly tied to the patent since the X-Sync included unclaimed features that may have contributed to its success."

This latest decision is expected to end the dispute. According to Bicycle Retailer, the litigation has cost both companies millions in legal fees. In its most recent quarterly and full-year results, Fox Factory stated it had spent $1.96 million in patent-related litigation in 2020 and $4.4 million the year before.

SRAM told Cycling Weekly that it did not wish to comment.

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Simon Smythe

Simon Smythe is a hugely experienced cycling tech writer, who has been writing for Cycling Weekly since 2003. Until recently he was our senior tech writer. In his cycling career Simon has mostly focused on time trialling with a national medal, a few open wins and his club's 30-mile record in his palmares. These days he spends most of his time testing road bikes, or on a tandem doing the school run with his younger son.