Quiver

2017 Trek Session DH 27.5 vs 2019 Specialized Demo Alloy 27.5

The Specialized Demo Alloy 27.5 size closest to your M is the M. Compare the M instead

What changes on the Specialized Demo Alloy 27.5

Compared with the Trek Session DH 27.5 in M, the Specialized Demo Alloy 27.5 in SHORT places the top of the head tube 11 mm higher and 13 mm further back, relative to the bottom bracket. Its wheelbase is 22 mm shorter, which can contribute to quicker direction changes.

Frame stack
+11 mm
Higher front end
Frame reach
−13 mm
Shorter frame reach
Wheelbase
−22 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 DH 27.5 numbers we have for size M are missing the seat angle. The numbers below still compare.

Geometry side by side

MeasurementTrek Session DH 27.5 MSpecialized Demo Alloy 27.5 SHORTDifference
Reach408395mm−13 mm
Stack603614mm+11 mm
Head tube angle64.2°63.5°−0.7°
Effective top tube590571mm−19 mm
Chainstay length443430mm−13 mm
Wheelbase12051183mm−22 mm
BB drop912mm+3 mm
BB height364342mm−22 mm
Standover793698mm−95 mm
Seat tube length426394mm−32 mm
Head tube length115105mm−10 mm
Seat tube anglenot listed74°

Differences are the Specialized Demo Alloy 27.5 minus the Trek Session DH 27.5. Full charts: 2017 Trek Session DH 27.5, 2019 Specialized Demo Alloy 27.5.

Where each sits in its class

Trek Session DH 27.5Specialized Demo Alloy 27.5

AggressivePositionUpright
CalmSteeringQuick
PlayfulBalancePlanted

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.

PartTrek Session DH 27.588 DH 27.5Specialized Demo Alloy 27.5Alloy 27.5
FrameTrek Alpha Platinumnot listed
ForkRockShox BoXXer RCRockShox BoXXer RC 27.5
ShifterSRAM X0 DHSRAM GX
DerailleurSRAM X01SRAM GX
CassetteSRAM GX DHSRAM PG-1030
ChainSRAM PC1110SRAM PC-1031
CranksetTruVativ DescendantSRAM Descendant
PedalsWellgo MG-1not listed
WheelsetDT Swiss FR2150not listed
TireBontrager G4 Team IssueSpecialized Butcher
BrakeSRAM Code RSRAM Guide RE
HandlebarBontrager Linenot listed
StemRace Face ChesterSpecialized two-piece
HeadsetFSA Orbitnot listed
SeatpostBontrager Rhythm Elitenot listed
SaddleBontrager Evoke 2Specialized Phenom Comp
Rear shocknot listedFox Van RC
Gripsnot listedSpecialized Sip Grip

Know what is on every bike.

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