What does FSR stand for in mountain bikes?
According to Mountain Bike Rider,
In case you were wondering what the ‘FSR’ acronym means, technically it means ‘Front Suspension and Rear [suspension]’. This is historical acronym that dates back to when suspension forks came out (Stumpjumpers with sus forks were dubbed ‘FS’). When rear suspension came along, they added the ‘R’, hence ‘FSR’.
It's a specialized term for their full squish or full suspension mountain bikes originating from the stumpjumper which had fs as a model acronym meaning front suspension as bikes progressed and became full suspension they just added and r so it would incorporate the new rear suspension as well so FSR= FRONT SUSPENSION & REAR