2018 Specialized Stumpjumper Pro 29/6Fattie vs 2020 Specialized Stumpjumper ST Alloy 29
The S is the Specialized Stumpjumper ST Alloy 29 size closest to your S Specialized Stumpjumper Pro 29/6Fattie. We match frame stack and reach. This is a geometry comparison, not a fit recommendation; stem, spacers, handlebars and saddle setup also affect your riding position.
What changes on the Specialized Stumpjumper ST Alloy 29
Compared with the Specialized Stumpjumper Pro 29/6Fattie in S, the Specialized Stumpjumper ST Alloy 29 in S places the top of the head tube at about the same height and 19 mm further forward, relative to the bottom bracket. Its wheelbase is 29 mm longer, which can contribute to stability at speed.
- Frame stack
- +1 mm
- About the same height
- Frame reach
- +19 mm
- Longer frame reach
- Wheelbase
- +29 mm
- Longer: steadier at speed
- Head angle
- −0.5°
- Slacker: calmer steering
- Chainstays
- ±0 mm
- About the same
The two frames
Specialized Stumpjumper Pro 29/6Fattie, SSpecialized Stumpjumper ST Alloy 29, SDrawn to scale and lined up at the bottom bracket.
Geometry side by side
| Measurement | Specialized Stumpjumper Pro 29/6Fattie S | Specialized Stumpjumper ST Alloy 29 S | Difference |
|---|---|---|---|
| Reach | 386mm | 405mm | +19 mm |
| Stack | 618mm | 619mm | +1 mm |
| Head tube angle | 67° | 66.5° | −0.5° |
| Seat tube angle | 74° | 74.8° | +0.8° |
| Effective top tube | 563mm | not listed | |
| Chainstay length | 437mm | 437mm | ±0 mm |
| Wheelbase | 1122mm | 1151mm | +29 mm |
| BB drop | 33mm | 33mm | ±0 mm |
| BB height | 338mm | 341mm | +3 mm |
| Standover | 754mm | 756mm | +2 mm |
| Seat tube length | 396mm | 380mm | −16 mm |
| Fork length | 560mm | 560mm | ±0 mm |
| Head tube length | 125mm | 100mm | −25 mm |
Differences are the Specialized Stumpjumper ST Alloy 29 minus the Specialized Stumpjumper Pro 29/6Fattie. Full charts: 2018 Specialized Stumpjumper Pro 29/6Fattie, 2020 Specialized Stumpjumper ST Alloy 29.
Where each sits in its class
Specialized Stumpjumper Pro 29/6FattieSpecialized Stumpjumper ST Alloy 29
Each bike is ranked against the other trail bikes on Quiver, on frame geometry alone. Not your hand position or ride feel.
What each ships with
The stock build of each bike's first listed trim. Parts that match are dimmed.
| Part | Specialized Stumpjumper Pro 29/6FattiePro 29/6Fattie | Specialized Stumpjumper ST Alloy 29 |
|---|---|---|
| Fork | Öhlins RXF 36 | not listed |
| Rear shock | Öhlins STX | not listed |
| Shifter | SRAM X01 Eagle | not listed |
| Derailleur | SRAM X01 Eagle | not listed |
| Cassette | SRAM X01 Eagle | not listed |
| Chain | SRAM X01 Eagle | not listed |
| Crankset | TruVativ Descendant | not listed |
| Tire | Specialized Butcher, Specialized Purgatory | not listed |
| Hub | DT Swiss 350 | not listed |
| Rim | Roval Traverse | not listed |
| Brake | SRAM Guide RS | not listed |
| Grips | Specialized Sip Grip | not listed |
| Seatpost | Specialized Command Post IRcc | not listed |
| Saddle | Specialized Henge Expert | not listed |
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