2020 Trek Session 27.5 vs 2018 Specialized Demo 8 Frameset
The EXTRA LONG is the Specialized Demo 8 Frameset size closest to your XL Trek Session 27.5. 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 Demo 8 Frameset
Compared with the Trek Session 27.5 in XL, the Specialized Demo 8 Frameset in EXTRA LONG places the top of the head tube 11 mm higher and 4 mm further forward, relative to the bottom bracket. Its wheelbase is 5 mm shorter, which can contribute to quicker direction changes.
- Frame stack
- +11 mm
- Higher front end
- Frame reach
- +4 mm
- Longer frame reach
- Wheelbase
- −5 mm
- Shorter: quicker to change direction
- Head angle
- −0.7°
- Slacker: calmer steering
- Chainstays
- −13 mm
- Shorter: livelier
The two frames
We can't draw these frames yet. The Trek Session 27.5 numbers we have for size XL are missing the seat angle. The numbers below still compare.
Geometry side by side
| Measurement | Trek Session 27.5 XL | Specialized Demo 8 Frameset EXTRA LONG | Difference |
|---|---|---|---|
| Reach | 456 | 460mm | +4 mm |
| Stack | 603 | 614mm | +11 mm |
| Head tube angle | 64.2° | 63.5° | −0.7° |
| Effective top tube | 638 | 636mm | −2 mm |
| Chainstay length | 443 | 430mm | −13 mm |
| Wheelbase | 1253 | 1248mm | −5 mm |
| BB drop | 9 | 12mm | +3 mm |
| BB height | 364 | 342mm | −22 mm |
| Standover | 775 | 698mm | −77 mm |
| Seat tube length | 456 | 367mm | −89 mm |
| Head tube length | 115 | 105mm | −10 mm |
| Seat tube angle | not listed | 74° | |
| Fork length | not listed | 590mm |
Differences are the Specialized Demo 8 Frameset minus the Trek Session 27.5. Full charts: 2020 Trek Session 27.5, 2018 Specialized Demo 8 Frameset.
Where each sits in its class
Trek Session 27.5Specialized Demo 8 Frameset
Each bike is ranked against the other downhill 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 | Trek Session 27.58 27.5 | Specialized Demo 8 FramesetS-Works Frameset |
|---|---|---|
| Frame | Trek Alpha Platinum | not listed |
| Fork | RockShox BoXXer Select | not listed |
| Shifter | SRAM GX DH | not listed |
| Derailleur | SRAM GX DH | not listed |
| Cassette | SRAM GX DH | not listed |
| Chain | SRAM PC1110 | not listed |
| Crankset | TruVativ Descendant DH | not listed |
| Bottom bracket | SRAM DUB | not listed |
| Pedals | Wellgo BO-87B | not listed |
| Wheelset | Bontrager Line DH 30 | not listed |
| Tire | Bontrager G4 Team Issue | not listed |
| Brake | SRAM Guide R | not listed |
| Handlebar | Bontrager Line | not listed |
| Stem | Bontrager Line | not listed |
| Headset | FSA Orbit | not listed |
| Seatpost | Bontrager Rhythm Elite | not listed |
| Saddle | Bontrager Arvada | not listed |
| Rear shock | not listed | Öhlins TTX |
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