CannondaleF-Si
Origin
The F-Si was Cannondale's flagship XC hardtail, conceived in Bedford, Pennsylvania as a successor to the Flash F29 and launched for model year 2015 to chase World Cup XC podiums. Its signature trick was the proprietary Lefty Ocho single-leg fork paired with an asymmetric Si rear triangle and Ai offset hub spacing, which let engineers run very short 429mm chainstays without sacrificing tyre clearance or wheel dish. The frame used Cannondale's BallisTec carbon layup, with a Hi-MOD version dropping under 900g. Throughout 2016-2022 it was the platform Manuel Fumic, Henrique Avancini and Anton Cooper raced on. By 2024 demand for pure hardtails collapsed as the lightweight Scalpel full-suspension took over the XC duties, and the F-Si quietly disappeared from Cannondale's global lineup, with the last 2024 Carbon 4 builds being run-out stock at dealers.
Specifications
- Frame
- BallisTec Carbon (Hi-MOD on top builds) with SAVE Micro-Suspension flex zones, PF30-83 BB, tapered head tube, Speed Release 12mm thru-axle and Ai Offset rear end. Hi-MOD frame ~900g — the lightest MTB frame Cannondale has built.
- Weight
- kg
- Drivetrain
- 1x12 across the range: Shimano XT/SLX (10-51) with HollowGram 34T crank on mid builds; SRAM X01/XX1 Eagle on premium; World Cup ran full SRAM XX1 Eagle.
- Brakes
- Hydraulic disc, model varies by trim: Shimano Deore 160/160mm (Carbon 3), Shimano XT (Carbon 2), SRAM Level T (lower) up to SRAM Level Ultimate (World Cup).
- Wheels
- 29" tubeless-ready. Mid builds: Stan's NoTubes Crest MK3 rims, Lefty 60 front hub + Shimano/HollowGram rear (12x148mm Boost with 6mm Ai offset). Carbon 2: HollowGram 23 carbon; World Cup: ENVE M525 carbon w/ DT Swiss hubs.
The verdict
- Exceptionally light and stiff — the ~900g Hi-MOD frame plus low-friction Lefty Ocho deliver rapid acceleration and a vivid sense of speed on climbs
- Short Ai-offset chainstays with neutral rear-wheel dish keep climbing traction and put down power efficiently
- Best-in-class ride quality for a hardtail: SAVE micro-suspension flex zones take the edge off rough trail
- Lefty Ocho offers serious fore/aft stiffness and excellent small-bump sensitivity in its 100mm travel
- Modern, more confident XC geometry (69° head angle) makes it stable yet playful, not twitchy
- Stock 2.1-2.25" tyres are too narrow for many trails — riders quickly want wider rubber
- Heavy reliance on proprietary parts (Lefty hub/fork, Ai offset, HollowGram) — you can't swap in standard wheels or a normal fork
- Lefty service and spare availability is harder/pricier than a conventional fork; intimidates buyers and dealers
- Reported cockpit ergonomics niggle: some brake/shifter combos sat awkwardly for the thumb
- Pure hardtail focus narrows appeal as lightweight full-suspension XC bikes (Scalpel) close the weight gap
Who it’s for
Where to buy Cannondale F-Si in Latvia
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