Suspension specialists Öhlins has issued a safety warning on the Öhlins 36 29/27.5 Air forks and all RXF 34 Air forks.
The forks are also specced on the 2017 Specialized Stumpjumper, Enduro and Fuse, plus the 2018 Specialized Stumpjumper, Enduro and Levo. All of these bikes are included in a forthcoming safety recall.
Öhlins has asked all riders using the forks to stop riding them and dealers to stop selling bikes equipped with the forks immediately.
A notice from Öhlins listed on its website states: "Based upon reports from the field, we've concluded the Öhlins RXF 36 29/27.5 Air forks and all RXF 34 Air forks sold to aftermarket and specced as original equipment on the 2017 Stumpjumper, Enduro, and Fuse, and the 2018 Stumpjumper, Enduro, Levo, may contain a defect in the top cap which potentially affects safety.
"Specifically, the right-side top cap on some forks may not be adequately torqued which in some cases may lead to the top cap working itself free through riding.
"When this happens the air cartridge may abruptly spring out of the stanchion tube causing a risk of injury to the rider. Therefore, we've decided to ask riders to stop riding, and our dealers to stop selling, affected forks and bicycles."
The recall statement also notes that other Öhlins forks, specifically the Öhlins RXF 36 Coil forks, are not affected by the notice.
Öhlins say it is working urgently in partnership with Specialized on a solution and once approved by necessary authorities, will issue a recall to fix the forks.