2026 Specialized Aethos 2 Pro vs 2026 Colnago V4Rs Shimano
The 51 is the Colnago V4Rs Shimano size closest to your 56 Specialized Aethos 2 Pro. 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 Colnago V4Rs Shimano
Compared with the Specialized Aethos 2 Pro in 56, the Colnago V4Rs Shimano in 51 places the top of the head tube 23 mm lower and 3 mm further back, relative to the bottom bracket.
- Frame stack
- −23 mm
- Lower front end
- Frame reach
- −3 mm
- Shorter frame reach
- Wheelbase
- n/a
- One of the bikes has no number for this
- Head angle
- −1.2°
- Slacker: calmer steering
- Chainstays
- −2 mm
- About the same
The two frames
Only the Specialized Aethos 2 Pro is drawn. The Colnago V4Rs Shimano numbers we have for size 51 are missing the wheelbase.
Geometry side by side
| Measurement | Specialized Aethos 2 Pro 56 | Colnago V4Rs Shimano 51 | Difference |
|---|---|---|---|
| Reach | 391 | 388 | −3 mm |
| Stack | 580 | 557 | −23 mm |
| Head tube angle | 73 | 71.8 | −1.2° |
| Seat tube angle | 74 | 74 | ±0.0° |
| Effective top tube | 557 | 550 | −7 mm |
| Chainstay length | 410 | 408 | −2 mm |
| Wheelbase | 998 | not listed | |
| BB drop | 75 | 72 | −3 mm |
| Head tube length | 169 | 148 | −21 mm |
| Seat tube length | not listed | 510 |
Differences are the Colnago V4Rs Shimano minus the Specialized Aethos 2 Pro. Full charts: 2026 Specialized Aethos 2 Pro, 2026 Colnago V4Rs Shimano.
Where each sits in its class
Specialized Aethos 2 ProColnago V4Rs Shimano
Each bike is ranked against the other road 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 | Specialized Aethos 2 ProPro | Colnago V4Rs ShimanoShimano Dura-Ace Di2 |
|---|---|---|
| Frame | Specialized Aethos 2 | Colnago V4Rs |
| Shifter | SRAM Force AXS E1 | Shimano Dura Ace Di2 |
| Derailleur | SRAM Force AXS E1 | Shimano Dura-Ace Di2, Shimano RD-9250 Dura-Ace Di2 |
| Cassette | SRAM Force | Shimano Dura-Ace |
| Chain | SRAM Force D1 | Shimano Dura-Ace |
| Crankset | SRAM Force E1 XPLR 1x | Shimano Dura-Ace |
| Chainring | SRAM Force E1 | Shimano Dura-Ace, Shimano Dura-Ace R9200 |
| Bottom bracket | SRAM DUB GX | CeramicSpeed T47 |
| Wheelset | Roval Alpinist CL II | Shimano Dura-Ace C50 |
| Tire | Specialized Turbo TLR Race | Pirelli P Zero Race |
| Brake | SRAM Force E1 | Shimano Dura-Ace Di2, Shimano Dura-Ace 9270 Di2 |
| Rotor | SRAM Force E1 | Shimano CL900 |
| Handlebar | Roval Alpinist Cockpit II | Colnago CC.01 |
| Stem | Roval Alpinist Cockpit II | Colnago CC.01 |
| Grips | Supacaz Super Sticky Kush | not listed |
| Seatpost | Roval Alpinist Carbon S-Works | Colnago D-shape carbon |
| Saddle | Specialized Power Pro Mirror | Prologo Scratch M5 CPC |
| Fork | not listed | Colnago carbon fork |
| Bar tape | not listed | Colnago Grip |
| Headset | not listed | CeramicSpeed SLT |
| Bottle cage | not listed | Colnago bottle cage |
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