2026 Specialized Stumpjumper 15 vs 2026 Forbidden Heathen Framekit
The S4 is the Forbidden Heathen Framekit size closest to your S6 Specialized Stumpjumper 15. 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 Forbidden Heathen Framekit
Compared with the Specialized Stumpjumper 15 in S6, the Forbidden Heathen Framekit in S4 places the top of the head tube 23 mm lower and 30 mm further back, relative to the bottom bracket. Its wheelbase is 56 mm shorter, which can contribute to quicker direction changes.
- Frame stack
- −23 mm
- Lower front end
- Frame reach
- −30 mm
- Shorter frame reach
- Wheelbase
- −56 mm
- Shorter: quicker to change direction
- Head angle
- ±0.0°
- About the same head angle
- Chainstays
- n/a
- One of the bikes has no number for this
The two frames
Only the Specialized Stumpjumper 15 is drawn. The Forbidden Heathen Framekit numbers we have for size S4 are missing the chainstay length.
Geometry side by side
| Measurement | Specialized Stumpjumper 15 S6 | Forbidden Heathen Framekit S4 | Difference |
|---|---|---|---|
| Reach | 525 | 495 | −30 mm |
| Stack | 671 | 648 | −23 mm |
| Head tube angle | 64 | 64 | ±0.0° |
| Seat tube angle | 76 | 76 | ±0.0° |
| Effective top tube | 678 | 657 | −21 mm |
| Chainstay length | 445 | not listed | |
| Wheelbase | 1327 | 1270.6 | −56 mm |
| BB drop | 35 | not listed | |
| BB height | 340 | 311 | −29 mm |
| Standover | 751 | 764 | +13 mm |
| Seat tube length | 465 | 470 | +5 mm |
| Fork length | not listed | 541 | |
| Head tube length | 155 | 120 | −35 mm |
Differences are the Forbidden Heathen Framekit minus the Specialized Stumpjumper 15. Full charts: 2026 Specialized Stumpjumper 15, 2026 Forbidden Heathen Framekit.
Where each sits in its class
Specialized Stumpjumper 15Forbidden Heathen Framekit
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 15S-Works | Forbidden Heathen Framekit |
|---|---|---|
| Frame | Specialized FACT 11m | not listed |
| Fork | Fox 36 Float Factory | not listed |
| Rear shock | Fox Float X Factory | not listed |
| Shifter | Shimano XTR M9250 | not listed |
| Derailleur | Shimano XTR Di2 | not listed |
| Cassette | Shimano XTR | not listed |
| Chain | Shimano XTR | not listed |
| Crankset | Shimano XTR | not listed |
| Chainring | Shimano XTR | not listed |
| Bottom bracket | Shimano BB93 | not listed |
| Wheelset | Roval Traverse SL II | not listed |
| Tire | Specialized Butcher, Specialized Eliminator | not listed |
| Hub | Industry Nine Hydra 2 | not listed |
| Brake | Shimano XTR | not listed |
| Rotor | Shimano XTR | not listed |
| Handlebar | Race Face Era Carbon | not listed |
| Stem | Race Face Turbine R | not listed |
| Grips | Deity Lockjaw | not listed |
| Dropper post | Fox Transfer NEO Factory | not listed |
| Saddle | Specialized S-Works Power | not listed |
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