2017 Trek Session 27.5 vs 2015 Specialized Demo
The SHORT is the Specialized Demo size closest to your S 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
Compared with the Trek Session 27.5 in S, the Specialized Demo in SHORT places the top of the head tube 11 mm higher and 6 mm further forward, relative to the bottom bracket.
- Frame stack
- +11 mm
- Higher front end
- Frame reach
- +6 mm
- Longer frame reach
- Wheelbase
- −1 mm
- About the same
- 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 S are missing the seat angle. The numbers below still compare.
Geometry side by side
| Measurement | Trek Session 27.5 S | Specialized Demo SHORT | Difference |
|---|---|---|---|
| Reach | 389 | 395mm | +6 mm |
| Stack | 603 | 614mm | +11 mm |
| Head tube angle | 64.2° | 63.5° | −0.7° |
| Effective top tube | 570 | 577mm | +7 mm |
| Chainstay length | 443 | 430mm | −13 mm |
| Wheelbase | 1185 | 1184mm | −1 mm |
| BB drop | -9 | not listed | |
| BB height | 364 | 343mm | −21 mm |
| Standover | 762 | 702mm | −60 mm |
| Seat tube length | 412 | 394mm | −18 mm |
| Head tube length | 150 | not listed | |
| Seat tube angle | not listed | 76° |
Differences are the Specialized Demo minus the Trek Session 27.5. Full charts: 2017 Trek Session 27.5, 2015 Specialized Demo.
Where each sits in its class
Trek Session 27.5Specialized Demo
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 |
|---|---|---|
| Frame | Trek Alpha Platinum | not listed |
| Fork | RockShox BoXXer RC | not listed |
| Shifter | SRAM GX DH | not listed |
| Derailleur | SRAM GX | not listed |
| Cassette | SRAM GX DH | not listed |
| Chain | SRAM PC1110 | not listed |
| Crankset | SRAM Descendant | not listed |
| Pedals | Wellgo BO-87B | not listed |
| Wheelset | DT Swiss FR2150 | not listed |
| Tire | Bontrager G4 Team Issue | not listed |
| Brake | SRAM Guide R | not listed |
| Handlebar | Bontrager Rhythm Elite | not listed |
| Headset | FSA Orbit | not listed |
| Seatpost | Bontrager Rhythm Elite | not listed |
| Saddle | Bontrager Evoke 2 | not listed |
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