Headset FSA NO.55R/558 1.5 ACR Retrofit w/TH-874-1 B1

FSA, or Full Speed Ahead, is an internationally recognized manufacturer of bicycle components. Its range includes wheels, cranksets, bottom brackets, chainrings, handlebars, stems, seatposts, headsets, brake components and other parts that directly affect a bike’s handling, stiffness, reliability and ride feel. The brand is strong across road, gravel, MTB and e-bike segments, and FSA components are used both as original equipment on new bikes and as aftermarket upgrades.

FSA’s strength lies in its broad and practical product range. It is not a brand focused on just one component — FSA offers complete solutions for the drivetrain, cockpit and control areas of the bike. Cranksets, chainrings and bottom brackets help ensure efficient power transfer; handlebars, stems and seatposts influence riding position and steering precision; headsets and smaller technical parts are often the components whose quality is most noticeable when they work smoothly for years without issues.

Among FSA’s best-known product series are K-Force, SL-K, Energy, Gossamer, Omega, Afterburner, Comet and Gradient. These cover different price levels and use cases, from lightweight race equipment to reliable everyday components. FSA uses both carbon fibre and aluminium alloys to find the right balance between weight, stiffness, durability and price.

On a road bike, FSA is associated above all with a precise and stiff cockpit, quality cranksets and a smoothly functioning drivetrain. On gravel and mountain bikes, durability, confident handling and reliability in changing conditions become especially important. FSA components are made for riders who want to repair or upgrade their bike with parts that create a noticeable difference in riding position, power transfer and control.

Materials, manufacturing precision and real-world riding experience all play an important role in FSA’s development work. The brand focuses on technology, innovation and production processes designed to deliver high-performance components at a reasonable price level. This makes FSA a strong choice both for riders building a bike from the ground up and for those who want to improve an existing bike in a practical and reliable way.

FSA’s philosophy is simple: every component should help the bike work better. Cranksets must transfer power directly, the handlebar and stem must provide confident control, bottom brackets and headsets must run smoothly, and every detail must withstand real riding. That is where FSA’s value lies — technical components that do not simply aim to stand out, but make the bike faster, more precise and more dependable.