2026 Forbidden Heathen Framekit vs 2026 Specialized Stumpjumper 15 Pro
The S3 is the Specialized Stumpjumper 15 Pro size closest to your S1 Forbidden Heathen Framekit. 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 15 Pro
Compared with the Forbidden Heathen Framekit in S1, the Specialized Stumpjumper 15 Pro in S3 places the top of the head tube 9 mm higher and 10 mm further forward, relative to the bottom bracket. Its wheelbase is 62 mm longer, which can contribute to stability at speed.
- Frame stack
- +9 mm
- Higher front end
- Frame reach
- +10 mm
- Longer frame reach
- Wheelbase
- +62 mm
- Longer: steadier at speed
- Head angle
- ±0.0°
- About the same head angle
- Chainstays
- n/a
- One of the bikes has no number for this
The two frames
We can't draw these frames yet. The Forbidden Heathen Framekit numbers we have for size S1 are missing the chainstay length. The numbers below still compare.
Geometry side by side
| Measurement | Forbidden Heathen Framekit S1 | Specialized Stumpjumper 15 Pro S3 | Difference |
|---|---|---|---|
| Reach | 435 | 445 | +10 mm |
| Stack | 621 | 630 | +9 mm |
| Head tube angle | 64 | 64 | ±0.0° |
| Seat tube angle | 76 | 76.5 | +0.5° |
| Effective top tube | 590 | 596 | +6 mm |
| Wheelbase | 1155.4 | 1217 | +62 mm |
| BB height | 301 | 340 | +39 mm |
| Standover | 716 | 745 | +29 mm |
| Seat tube length | 400 | 405 | +5 mm |
| Fork length | 541 | not listed | |
| Head tube length | 90 | 110 | +20 mm |
| Chainstay length | not listed | 435 | |
| BB drop | not listed | 35 |
Differences are the Specialized Stumpjumper 15 Pro minus the Forbidden Heathen Framekit. Full charts: 2026 Forbidden Heathen Framekit, 2026 Specialized Stumpjumper 15 Pro.
Where each sits in its class
Forbidden Heathen FramekitSpecialized Stumpjumper 15 Pro
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 | Forbidden Heathen Framekit | Specialized Stumpjumper 15 ProPro |
|---|---|---|
| Frame | not listed | Specialized Stumpjumper 15 |
| Fork | not listed | Fox 36 Factory |
| Rear shock | not listed | Fox Float X Factory |
| Shifter | not listed | SRAM AXS POD Rocker |
| Derailleur | not listed | SRAM X0 Eagle Transmission |
| Cassette | not listed | SRAM 1295 X01 |
| Crankset | not listed | SRAM X0 Eagle Transmission |
| Chainring | not listed | SRAM 32 |
| Bottom bracket | not listed | SRAM DUB GX |
| Wheelset | not listed | Roval Traverse SL II |
| Tire | not listed | Specialized Butcher, Specialized Eliminator |
| Brake | not listed | SRAM Maven Silver Stealth |
| Rotor | not listed | SRAM CenterLine |
| Handlebar | not listed | Deity Speedway |
| Dropper post | not listed | BikeYoke Revive Max 3.0 |
| Saddle | not listed | Specialized Bridge Expert |
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