2021 Trek Session 27.5 vs 2023 Specialized Demo Expert
The S2 is the Specialized Demo Expert size closest to your L 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 Expert
Compared with the Trek Session 27.5 in L, the Specialized Demo Expert in S2 places the top of the head tube 29 mm higher and 6 mm further back, relative to the bottom bracket. Its wheelbase is 10 mm longer, which can contribute to stability at speed.
- Frame stack
- +29 mm
- Higher front end
- Frame reach
- −6 mm
- Shorter frame reach
- Wheelbase
- +10 mm
- Longer: steadier at speed
- Head angle
- −1.4°
- Slacker: calmer steering
- Chainstays
- +5 mm
- Longer: more planted
The two frames
We can't draw these frames yet. The Trek Session 27.5 numbers we have for size L are missing the seat angle. The numbers below still compare.
Geometry side by side
| Measurement | Trek Session 27.5 L | Specialized Demo Expert S2 | Difference |
|---|---|---|---|
| Reach | 432 | 426mm | −6 mm |
| Stack | 603 | 632mm | +29 mm |
| Head tube angle | 64.2° | 62.8° | −1.4° |
| Effective top tube | 614 | not listed | |
| Chainstay length | 443 | 448mm | +5 mm |
| Wheelbase | 1229 | 1239mm | +10 mm |
| BB drop | 9 | not listed | |
| BB height | 364 | not listed | |
| Standover | 790 | not listed | |
| Seat tube length | 456 | 394mm | −62 mm |
| Head tube length | 115 | 105mm | −10 mm |
| Seat tube angle | not listed | 78.2° |
Differences are the Specialized Demo Expert minus the Trek Session 27.5. Full charts: 2021 Trek Session 27.5, 2023 Specialized Demo Expert.
Where each sits in its class
Trek Session 27.5Specialized Demo Expert
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 ExpertExpert |
|---|---|---|
| Frame | Trek Alpha Platinum | not listed |
| Fork | RockShox BoXXer Select | RockShox BoXXer 29 |
| Shifter | SRAM GX DH | SRAM GX DH |
| Derailleur | SRAM GX DH | SRAM GX DH |
| Cassette | SRAM GX DH | SRAM GX DH |
| Chain | SRAM PC1110 | SRAM PC1110 |
| Crankset | TruVativ Descendant DH | Specialized DESCENDANT DH |
| Bottom bracket | SRAM DUB | SRAM DUB |
| Pedals | Wellgo BO-87B | not listed |
| Wheelset | Bontrager Line DH 30 | not listed |
| Tire | Bontrager G4 Team Issue | Specialized Butcher |
| Brake | SRAM Guide R | SRAM Code RS |
| Handlebar | Bontrager Line | not listed |
| Stem | Bontrager Line | Specialized Descendant |
| Headset | FSA Orbit | not listed |
| Seatpost | Bontrager Rhythm Elite | not listed |
| Saddle | Bontrager Arvada | Specialized Henge DH |
| Rear shock | not listed | RockShox Super Deluxe Select |
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