The Series One was FIT’s first frame when they started back in 2000, and its their most popular bike to date. For 2026, they have upgraded to a CNC-machined Integrated headtube and a fully sealed bearing front hub. The S1 frame and fork have been lightened up and offered in 3 top tube sizes with corresponding handlebar and crank sizes.

Specifications
Frame: Cro-Mo Front Tri
Geometry: SERIES ONE
Headset: Integrated w/Gyro Holes
BB: Mid Sealed
Bars: 20.25/20.5TT 2-Piece 8.7x 29, 20.75TT 2-Piece 9 x 29
Fork: Cro-Mo Steerer, 33mm Offset, Welded Insert
Stem: FIT Top Load
Seat: More Padded Integrated Combo, 200mm Post
Cranks: Tubular Cro-Mo. 20.25TT 160mm, 20.5TT 165mm, 20.75TT 170mm
Sprocket: FIT Key 25T
Pedals: FIT PC
Front Wheel: FIT S1W Rim w/Sealed Hub
Rear Wheel: FIT S1W Rim w/Sealed 9T Cassette
Tyres: FIT OEM 2.4
Brakes: U-Brake w/Low Tension Springs, Two Finger Lever, Linear Cable
Misc: Sealed Front Hub/ Integrated HT New for 2026