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2025 Specialized Aethos vs 2026 Specialized Tarmac SL8 Pro Shimano

The Specialized Tarmac SL8 Pro Shimano size closest to your 54 is the 54. Compare the 54 instead

What changes on the Specialized Tarmac SL8 Pro Shimano

Compared with the Specialized Aethos in 54, the Specialized Tarmac SL8 Pro Shimano in 61 places the top of the head tube 68 mm higher and 24 mm further forward, relative to the bottom bracket.

Frame stack
+68 mm
Higher front end
Frame reach
+24 mm
Longer frame reach
Wheelbase
n/a
One of the bikes has no number for this
Head angle
+1.0°
Steeper: sharper steering
Chainstays
±0 mm
About the same

The two frames

2025 Specialized Aethos (54)The Specialized Aethos frame drawn to scale.J 978

Only the Specialized Aethos is drawn. The Specialized Tarmac SL8 Pro Shimano numbers we have for size 61 are missing the wheelbase.

Geometry side by side

MeasurementSpecialized Aethos 54Specialized Tarmac SL8 Pro Shimano 61Difference
Reach384mm408+24 mm
Stack544mm612+68 mm
Head tube angle73°74+1.0°
Seat tube angle74°73−1.0°
Effective top tube540mmnot listed
Chainstay length410mm410±0 mm
Wheelbase978mmnot listed
BB drop72mmnot listed
BB height268mmnot listed
Standover748mmnot listed
Seat tube length481mmnot listed
Fork length369mmnot listed
Head tube length137mm204+67 mm

Differences are the Specialized Tarmac SL8 Pro Shimano minus the Specialized Aethos. Full charts: 2025 Specialized Aethos, 2026 Specialized Tarmac SL8 Pro Shimano.

Where each sits in its class

Specialized AethosSpecialized Tarmac SL8 Pro Shimano

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 Pro ShimanoPro - Shimano Ultegra Di2
Framenot listedSpecialized Tarmac SL8
Forknot listedSpecialized FACT 10r
Shifternot listedShimano Ultegra R8170
Derailleurnot listedShimano Ultegra R8150 Di2
Cassettenot listedShimano Ultegra
Chainnot listedShimano XT M8100
Cranksetnot listedShimano Ultegra R81000
Bottom bracketnot listedShimano Threaded BSA
Wheelsetnot listedRoval Rapide CL III
Tirenot listedSpecialized S-Works Turbo
Brakenot listedShimano Ultegra R8170
Rotornot listedShimano Ultegra R8170
Handlebarnot listedRoval Rapide Cockpit
Stemnot listedRoval Rapide Cockpit
Bar tapenot listedSupacaz Super Sticky Kush
Seatpostnot listedSpecialized S-Works Tarmac SL8
Saddlenot listedSpecialized Power Pro

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