Quiver

2023 Specialized Aethos vs 2025 Specialized Tarmac SL8 Expert

The 52 is the Specialized Tarmac SL8 Expert size closest to your 52 Specialized Aethos. 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 Tarmac SL8 Expert

Compared with the Specialized Aethos in 52, the Specialized Tarmac SL8 Expert in 52 places the top of the head tube at about the same height and about as far forward, relative to the bottom bracket.

Frame stack
±0 mm
About the same height
Frame reach
±0 mm
About the same reach
Wheelbase
±0 mm
About the same
Head angle
±0.0°
About the same head angle
Chainstays
±0 mm
About the same

The two frames

2023 Specialized Aethos (52) and 2025 Specialized Tarmac SL8 Expert (52), lined up at the bottom bracketBoth frames drawn to scale. The Specialized Aethos is drawn in full with its measurements, and the Specialized Tarmac SL8 Expert is the colored outline on top.J 975

Specialized Aethos, 52Specialized Tarmac SL8 Expert, 52Drawn to scale and lined up at the bottom bracket.

Geometry side by side

MeasurementSpecialized Aethos 52Specialized Tarmac SL8 Expert 52Difference
Reach380mm380±0 mm
Stack527mm527±0 mm
Head tube angle72.5°72.5±0.0°
Seat tube angle74°74±0.0°
Chainstay length410mm410±0 mm
Wheelbase975mm975±0 mm
BB drop74mm75+1 mm
BB height266mm266±0 mm
Standover728mm746+18 mm
Seat tube length462mm456−6 mm
Fork length369mm370+1 mm
Head tube length120mm120±0 mm

Differences are the Specialized Tarmac SL8 Expert minus the Specialized Aethos. Full charts: 2023 Specialized Aethos, 2025 Specialized Tarmac SL8 Expert.

Where each sits in its class

Specialized AethosSpecialized Tarmac SL8 Expert

AggressivePositionUpright
CalmSteeringQuick
PlayfulBalancePlanted

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.

PartSpecialized AethosSpecialized Tarmac SL8 ExpertExpert
Framenot listedSpecialized Tarmac SL8 FACT
Forknot listedSpecialized FACT 10r Carbon
Shifternot listedShimano Ultegra R8170 Di2
Derailleurnot listedShimano Ultegra R8150 Di2, Shimano Ultegra R8150 Di2 front
Cassettenot listedShimano Ultegra
Chainnot listedShimano Ultegra
Cranksetnot listedShimano Ultegra R8100
Chainringnot listedShimano Ultegra
Bottom bracketnot listedShimano Ultegra
Wheelsetnot listedRoval C38
Tirenot listedSpecialized S-Works Turbo
Brakenot listedShimano Ultegra R8170 Di2, Shimano Ultegra R8170 Di2 rear
Rotornot listedShimano Ultegra
Handlebarnot listedSpecialized Expert Shallow Drop
Stemnot listedSpecialized Tarmac
Bar tapenot listedSupacaz Super Sticky Kush
Headsetnot listedIntegrated
Seatpostnot listedSpecialized S-Works Tarmac SL8
Saddlenot listedSpecialized Power Expert

Know what is on every bike.

Add your bike to Quiver. Keep its parts, setup, and service history together, then share your build.

Explore the app
A Transition Relay build sheet: frame, fork, shock and drivetrainThe Relay’s ride photo galleryThe Relay’s ride spectrum and 2D frame geometryThe garage: five bikes and 99 recorded partsA Specialized Tarmac SL8 road build sheet