bike geometry

Tarmac SL8 2025

Name: Tarmac SL8 2025
Brand: Specialized

Compare size-specific bike geometry, including reach, stack, angles, wheelbase and the measurements that influence fit and handling.

Specialized › Tarmac SL8 › Standard › Tarmac SL8

Tarmac SL8 geometry measurements

Choose the recorded size and configuration. Geometry figures can change by size; RideDNA does not collapse those values into one misleading answer.

What is the reach of the Tarmac SL8?

Reach is the horizontal distance from the bottom bracket to the top of the head tube. Also searched as frame reach.

Configuration	Size	Reach	Source
Tarmac SL8 geometry	54	385 mm	RideDNA-derived
Tarmac SL8 geometry	44	366.6 mm	RideDNA-derived
Tarmac SL8 geometry	52	379.8 mm	RideDNA-derived
Tarmac SL8 geometry	56	395.7 mm	RideDNA-derived
Tarmac SL8 geometry	58	402 mm	RideDNA-derived
Tarmac SL8 geometry	61	408 mm	RideDNA-derived
Tarmac SL8 geometry	49	376 mm	RideDNA-derived

What is the stack of the Tarmac SL8?

Stack is the vertical distance from the bottom bracket to the top of the head tube. Also searched as frame stack.

Configuration	Size	Stack	Source
Tarmac SL8 geometry	54	544 mm	RideDNA-derived
Tarmac SL8 geometry	44	500.4 mm	RideDNA-derived
Tarmac SL8 geometry	52	527.2 mm	RideDNA-derived
Tarmac SL8 geometry	56	564.8 mm	RideDNA-derived
Tarmac SL8 geometry	58	590.7 mm	RideDNA-derived
Tarmac SL8 geometry	61	611.6 mm	RideDNA-derived
Tarmac SL8 geometry	49	514.2 mm	RideDNA-derived

What is the effective top tube of the Tarmac SL8?

Effective top tube is the horizontal distance between the head-tube and seat-tube centerlines. Also searched as ETT, virtual top tube, horizontal top tube.

Configuration	Size	Effective top tube	Source
Tarmac SL8 geometry	54	541 mm	RideDNA-derived
Tarmac SL8 geometry	44	496 mm	RideDNA-derived
Tarmac SL8 geometry	52	531 mm	RideDNA-derived
Tarmac SL8 geometry	56	563 mm	RideDNA-derived
Tarmac SL8 geometry	58	577 mm	RideDNA-derived
Tarmac SL8 geometry	61	595 mm	RideDNA-derived
Tarmac SL8 geometry	49	509 mm	RideDNA-derived

What is the head tube angle of the Tarmac SL8?

Head tube angle describes the steering-axis angle relative to the ground. Also searched as HTA, head angle, steering angle.

Configuration	Size	Head tube angle	Source
Tarmac SL8 geometry	54	73 °	RideDNA-derived
Tarmac SL8 geometry	44	70.5 °	RideDNA-derived
Tarmac SL8 geometry	52	72.5 °	RideDNA-derived
Tarmac SL8 geometry	56	73.5 °	RideDNA-derived
Tarmac SL8 geometry	58	73.5 °	RideDNA-derived
Tarmac SL8 geometry	61	74 °	RideDNA-derived
Tarmac SL8 geometry	49	71.75 °	RideDNA-derived

What is the seat tube angle of the Tarmac SL8?

Seat tube angle describes the seat-tube angle relative to the ground. Also searched as STA, seat angle, effective seat angle.

Configuration	Size	Seat tube angle	Source
Tarmac SL8 geometry	54	74 °	RideDNA-derived
Tarmac SL8 geometry	44	75.5 °	RideDNA-derived
Tarmac SL8 geometry	52	74 °	RideDNA-derived
Tarmac SL8 geometry	56	73.5 °	RideDNA-derived
Tarmac SL8 geometry	58	73.5 °	RideDNA-derived
Tarmac SL8 geometry	61	73 °	RideDNA-derived
Tarmac SL8 geometry	49	75.5 °	RideDNA-derived

What is the wheelbase of the Tarmac SL8?

Wheelbase is the distance between the front and rear wheel axles. Also searched as axle-to-axle length.

Configuration	Size	Wheelbase	Source
Tarmac SL8 geometry	54	979 mm	RideDNA-derived
Tarmac SL8 geometry	44	970.7 mm	RideDNA-derived
Tarmac SL8 geometry	52	975.3 mm	RideDNA-derived
Tarmac SL8 geometry	56	991.2 mm	RideDNA-derived
Tarmac SL8 geometry	58	1005.2 mm	RideDNA-derived
Tarmac SL8 geometry	61	1012.1 mm	RideDNA-derived
Tarmac SL8 geometry	49	973.9 mm	RideDNA-derived

What is the chainstay length of the Tarmac SL8?

Chainstay length, also called rear center, is the distance from the bottom bracket to the rear axle. Also searched as Chainstay, rear center, rear centre.

Configuration	Size	Chainstay length	Source
Tarmac SL8 geometry	54	403.6 mm	RideDNA-derived
Tarmac SL8 geometry	44	403.3 mm	RideDNA-derived
Tarmac SL8 geometry	52	403.3 mm	RideDNA-derived
Tarmac SL8 geometry	56	403.6 mm	RideDNA-derived
Tarmac SL8 geometry	58	403.6 mm	RideDNA-derived
Tarmac SL8 geometry	61	403.6 mm	RideDNA-derived
Tarmac SL8 geometry	49	403.3 mm	RideDNA-derived

What is the bottom bracket height of the Tarmac SL8?

Bottom bracket height is the vertical distance from the ground to the bottom bracket. Also searched as BB height.

Configuration	Size	Bottom bracket height	Source
Tarmac SL8 geometry	54	267 mm	RideDNA-derived
Tarmac SL8 geometry	44	265 mm	RideDNA-derived
Tarmac SL8 geometry	52	265 mm	RideDNA-derived
Tarmac SL8 geometry	56	267 mm	RideDNA-derived
Tarmac SL8 geometry	58	267 mm	RideDNA-derived
Tarmac SL8 geometry	61	267 mm	RideDNA-derived
Tarmac SL8 geometry	49	265 mm	RideDNA-derived

What is the front center of the Tarmac SL8?

Front center is the distance from the bottom bracket to the front wheel axle. Also searched as front centre.

Configuration	Size	Front center	Source
Tarmac SL8 geometry	54	579.8 mm	RideDNA-derived
Tarmac SL8 geometry	44	572.2 mm	RideDNA-derived
Tarmac SL8 geometry	52	576.8 mm	RideDNA-derived
Tarmac SL8 geometry	56	592 mm	RideDNA-derived
Tarmac SL8 geometry	58	605.9 mm	RideDNA-derived
Tarmac SL8 geometry	61	612.8 mm	RideDNA-derived
Tarmac SL8 geometry	49	575.4 mm	RideDNA-derived

What is the fork offset of the Tarmac SL8?

Fork offset is the perpendicular distance between the steering axis and the front axle. Also searched as fork rake, rake.

Configuration	Size	Fork offset	Source
Tarmac SL8 geometry	54	44 mm	RideDNA-derived
Tarmac SL8 geometry	44	47 mm	RideDNA-derived
Tarmac SL8 geometry	52	47 mm	RideDNA-derived
Tarmac SL8 geometry	56	44 mm	RideDNA-derived
Tarmac SL8 geometry	58	44 mm	RideDNA-derived
Tarmac SL8 geometry	61	44 mm	RideDNA-derived
Tarmac SL8 geometry	49	47 mm	RideDNA-derived

What is the head tube length of the Tarmac SL8?

Head tube length is the measured length of the frame's head tube. Also searched as Head tube, head tube.

Configuration	Size	Head tube length	Source
Tarmac SL8 geometry	54	137 mm	RideDNA-derived
Tarmac SL8 geometry	44	99 mm	RideDNA-derived
Tarmac SL8 geometry	52	120 mm	RideDNA-derived
Tarmac SL8 geometry	56	157 mm	RideDNA-derived
Tarmac SL8 geometry	58	184 mm	RideDNA-derived
Tarmac SL8 geometry	61	204 mm	RideDNA-derived
Tarmac SL8 geometry	49	109 mm	RideDNA-derived

What is the seat tube length of the Tarmac SL8?

Seat tube length is the recorded length of the frame's seat tube; measurement conventions can differ by manufacturer. Also searched as Seat tube, seat tube, frame size.

Configuration	Size	Seat tube length	Source
Tarmac SL8 geometry	54	473 mm	RideDNA-derived
Tarmac SL8 geometry	44	433 mm	RideDNA-derived
Tarmac SL8 geometry	52	456 mm	RideDNA-derived
Tarmac SL8 geometry	56	494 mm	RideDNA-derived
Tarmac SL8 geometry	58	515 mm	RideDNA-derived
Tarmac SL8 geometry	61	545 mm	RideDNA-derived
Tarmac SL8 geometry	49	445 mm	RideDNA-derived

What is the standover height of the Tarmac SL8?

Standover height is the ground-to-top-tube height at the manufacturer's stated measurement point. Also searched as Standover, stand over height, standover clearance.

Configuration	Size	Standover height	Source
Tarmac SL8 geometry	54	739.9 mm	RideDNA-derived
Tarmac SL8 geometry	44	698.2 mm	RideDNA-derived
Tarmac SL8 geometry	52	721.3 mm	RideDNA-derived
Tarmac SL8 geometry	56	759.9 mm	RideDNA-derived
Tarmac SL8 geometry	58	782.9 mm	RideDNA-derived
Tarmac SL8 geometry	61	807.1 mm	RideDNA-derived
Tarmac SL8 geometry	49	710.9 mm	RideDNA-derived

What is the fork length of the Tarmac SL8?

Fork length is the axle-to-crown distance recorded for the fork. Also searched as axle to crown, A2C.

Configuration	Size	Fork length	Source
Tarmac SL8 geometry	54	370 mm	RideDNA-derived
Tarmac SL8 geometry	44	370 mm	RideDNA-derived
Tarmac SL8 geometry	52	370 mm	RideDNA-derived
Tarmac SL8 geometry	56	370 mm	RideDNA-derived
Tarmac SL8 geometry	58	370 mm	RideDNA-derived
Tarmac SL8 geometry	61	370 mm	RideDNA-derived
Tarmac SL8 geometry	49	370 mm	RideDNA-derived

What is the wheel flop of the Tarmac SL8?

Wheel flop is a calculated steering-geometry value based on trail and head tube angle. Also searched as flop.

Configuration	Size	Wheel flop	Source
Tarmac SL8 geometry	54	16.1 mm	RideDNA-derived
Tarmac SL8 geometry	44	22.1 mm	RideDNA-derived
Tarmac SL8 geometry	52	16.5 mm	RideDNA-derived
Tarmac SL8 geometry	56	14.8 mm	RideDNA-derived
Tarmac SL8 geometry	58	14.8 mm	RideDNA-derived
Tarmac SL8 geometry	61	13.6 mm	RideDNA-derived
Tarmac SL8 geometry	49	18.5 mm	RideDNA-derived

Geometry

Available sizes: 54, 44, 52, 56, 58, 61, 49.

Tarmac SL8 geometry

Jump to size: 44 · 49 · 52 · 54 · 56 · 58 · 61

Tarmac SL8 geometry geometry by size
Size	Reach	Stack	ETT	HTA	STA	Trail	Wheelbase	Chainstay	BB drop	BB height	Front center	Fork offset	Head tube	Seat tube	Standover	Fork length	Wheel flop	Max tire
44	366.6 mm	500.4 mm	496 mm	70.5 °	75.5 °	—	970.7 mm	403.3 mm	—	265 mm	572.2 mm	47 mm	99 mm	433 mm	698.2 mm	370 mm	22.1 mm	—
49	376 mm	514.2 mm	509 mm	71.75 °	75.5 °	—	973.9 mm	403.3 mm	—	265 mm	575.4 mm	47 mm	109 mm	445 mm	710.9 mm	370 mm	18.5 mm	—
52	379.8 mm	527.2 mm	531 mm	72.5 °	74 °	—	975.3 mm	403.3 mm	—	265 mm	576.8 mm	47 mm	120 mm	456 mm	721.3 mm	370 mm	16.5 mm	—
54	385 mm	544 mm	541 mm	73 °	74 °	—	979 mm	403.6 mm	—	267 mm	579.8 mm	44 mm	137 mm	473 mm	739.9 mm	370 mm	16.1 mm	—
56	395.7 mm	564.8 mm	563 mm	73.5 °	73.5 °	—	991.2 mm	403.6 mm	—	267 mm	592 mm	44 mm	157 mm	494 mm	759.9 mm	370 mm	14.8 mm	—
58	402 mm	590.7 mm	577 mm	73.5 °	73.5 °	—	1005.2 mm	403.6 mm	—	267 mm	605.9 mm	44 mm	184 mm	515 mm	782.9 mm	370 mm	14.8 mm	—
61	408 mm	611.6 mm	595 mm	74 °	73 °	—	1012.1 mm	403.6 mm	—	267 mm	612.8 mm	44 mm	204 mm	545 mm	807.1 mm	370 mm	13.6 mm	—

Length measurements are in millimeters; HTA and STA are in degrees. ETT means effective top tube.

Size-to-size changes

Differences are calculated from the recorded values; they are not fit recommendations.

Tarmac SL8 geometry: 44 → 49 — Reach +9.4 mm, Stack +13.8 mm, ETT +13 mm, HTA +1.25 °, STA +0 °, Wheelbase +3.2 mm, Chainstay +0 mm, BB height +0 mm, Front center +3.2 mm, Fork offset +0 mm, Head tube +10 mm, Seat tube +12 mm, Standover +12.7 mm, Fork length +0 mm, Wheel flop -3.6 mm
Tarmac SL8 geometry: 49 → 52 — Reach +3.8 mm, Stack +13 mm, ETT +22 mm, HTA +0.75 °, STA -1.5 °, Wheelbase +1.4 mm, Chainstay +0 mm, BB height +0 mm, Front center +1.4 mm, Fork offset +0 mm, Head tube +11 mm, Seat tube +11 mm, Standover +10.4 mm, Fork length +0 mm, Wheel flop -2 mm
Tarmac SL8 geometry: 52 → 54 — Reach +5.2 mm, Stack +16.8 mm, ETT +10 mm, HTA +0.5 °, STA +0 °, Wheelbase +3.7 mm, Chainstay +0.3 mm, BB height +2 mm, Front center +3 mm, Fork offset -3 mm, Head tube +17 mm, Seat tube +17 mm, Standover +18.6 mm, Fork length +0 mm, Wheel flop -0.4 mm
Tarmac SL8 geometry: 54 → 56 — Reach +10.7 mm, Stack +20.8 mm, ETT +22 mm, HTA +0.5 °, STA -0.5 °, Wheelbase +12.2 mm, Chainstay +0 mm, BB height +0 mm, Front center +12.2 mm, Fork offset +0 mm, Head tube +20 mm, Seat tube +21 mm, Standover +20 mm, Fork length +0 mm, Wheel flop -1.3 mm
Tarmac SL8 geometry: 56 → 58 — Reach +6.3 mm, Stack +25.9 mm, ETT +14 mm, HTA +0 °, STA +0 °, Wheelbase +14 mm, Chainstay +0 mm, BB height +0 mm, Front center +13.9 mm, Fork offset +0 mm, Head tube +27 mm, Seat tube +21 mm, Standover +23 mm, Fork length +0 mm, Wheel flop +0 mm
Tarmac SL8 geometry: 58 → 61 — Reach +6 mm, Stack +20.9 mm, ETT +18 mm, HTA +0.5 °, STA -0.5 °, Wheelbase +6.9 mm, Chainstay +0 mm, BB height +0 mm, Front center +6.9 mm, Fork offset +0 mm, Head tube +20 mm, Seat tube +30 mm, Standover +24.2 mm, Fork length +0 mm, Wheel flop -1.2 mm

RideDNA-derived values

These deterministic calculations use the recorded manufacturer inputs above. They are separate from manufacturer facts and are not fit recommendations.

Tarmac SL8 geometry size 54 stack Reach Ratio: 1.41
Tarmac SL8 geometry size 44 stack Reach Ratio: 1.36
Tarmac SL8 geometry size 52 stack Reach Ratio: 1.39
Tarmac SL8 geometry size 56 stack Reach Ratio: 1.43
Tarmac SL8 geometry size 58 stack Reach Ratio: 1.47
Tarmac SL8 geometry size 61 stack Reach Ratio: 1.5
Tarmac SL8 geometry size 49 stack Reach Ratio: 1.37