Quiver

2025 Specialized Tarmac SL8 SRAM vs 2025 Specialized Aethos Pro

The Specialized Aethos Pro size closest to your 54 is the 54. Compare the 54 instead

What changes on the Specialized Aethos Pro

Compared with the Specialized Tarmac SL8 SRAM in 54, the Specialized Aethos Pro in 61 places the top of the head tube 68 mm higher and 24 mm further forward, relative to the bottom bracket. Its wheelbase is 34 mm longer, which can contribute to stability at speed.

Frame stack
+68 mm
Higher front end
Frame reach
+24 mm
Longer frame reach
Wheelbase
+34 mm
Longer: steadier at speed
Head angle
+1.0°
Steeper: sharper steering
Chainstays
±0 mm
About the same

The two frames

2025 Specialized Tarmac SL8 SRAM (54) and 2025 Specialized Aethos Pro (61), lined up at the bottom bracketBoth frames drawn to scale. The Specialized Tarmac SL8 SRAM is drawn in full with its measurements, and the Specialized Aethos Pro is the colored outline on top.J 978

Specialized Tarmac SL8 SRAM, 54Specialized Aethos Pro, 61Drawn to scale and lined up at the bottom bracket.

Geometry side by side

MeasurementSpecialized Tarmac SL8 SRAM 54Specialized Aethos Pro 61Difference
Reach384mm408mm+24 mm
Stack544mm612mm+68 mm
Head tube angle73°74°+1.0°
Seat tube angle74°73°−1.0°
Effective top tube541mm595mm+54 mm
Chainstay length410mm410mm±0 mm
Wheelbase978mm1012mm+34 mm
BB drop72mm72mm±0 mm
BB height268mm268mm±0 mm
Standover768mm824mm+56 mm
Seat tube length473mm567mm+94 mm
Fork length370mm369mm−1 mm
Head tube length137mm204mm+67 mm

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

Where each sits in its class

Specialized Tarmac SL8 SRAMSpecialized Aethos Pro

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 Tarmac SL8 SRAMS-Works - SRAM RED AXSSpecialized Aethos Pro
FrameSpecialized S-Works Tarmac SL8 FACTnot listed
ShifterSRAM RED AXSnot listed
CassetteSRAM RED XG-1290not listed
ChainSRAM REDnot listed
CranksetSRAM RED AXS Power Meternot listed
Bottom bracketSRAM DUBnot listed
WheelsetRoval Rapide CLX IInot listed
TireSpecialized S-Works Turbo Rapidair 2Brnot listed
BrakeSRAM Red AXSnot listed
HandlebarRoval Rapide Cockpitnot listed
StemRoval Rapide Cockpitnot listed
SaddleSpecialized S-Works Powernot listed

Know what is on every bike.

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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