Open the comparison tool

Specialized Tarmac SL8 geometryRoad · 2026 · 7 sizes, from 44 to 61

The Specialized Tarmac SL8 is a road bike available in 7 sizes, from 44 to 61. Stack ranges from 501 to 612 mm and reach from 366 to 408 mm. Its position sits between racing and endurance. All sizes share 410 mm chainstays.

Stack501–612mm
Reach366–408mm
Head angle70.5–74.0°
Chainstay length410mm
Lively

What size Tarmac SL8 do I need?

Enter the stack and reach of a bike that fits you well and we will tell you which size is closest and how to set it up.

Compare on Fitbikefy →
44S 501 · R 366
49S 514 · R 375
52S 527 · R 380
54S 544 · R 384
56S 565 · R 395
58S 591 · R 402
61S 612 · R 408

Enter your stack and reach to see which size fits you best.

Geometry chart by size

Measurements in mm and degrees, as published by Specialized. The ones that matter most for choosing a size are in bold.

Size44495254565861
Stack501514527544565591612
Reach366375380384395402408
Effective top tube496509531541563577595
Head tube length99109120137157184204
Head angle70.5°71.8°72.5°73.0°73.5°73.5°74.0°
Chainstay length410410410410410410410
Wheelbase9709739759789911,0061,013
Front centre572574577579592606613
BB drop74747472727272
BB height266266266268268268268
Fork length370370370370370370370
Fork offset47474744444444
Trail71635858555552
Standover723735746768786808834
Seat tube (method not stated)433445456473494515545
Seat angle (method not stated)75.5°75.5°74.0°74.0°73.5°73.5°73.0°

Source: Specialized official website · data from 11 Nov 2026.

Spot a mistake in this data?

Thanks for letting us know. We’ll check it and fix it in the next update.

Specialized Tarmac SL8 2026

It is sent from your own email. We don’t store any data.

Stack and reach of every size

Higher means a taller front end; further right means a longer reach. The blue dot is your search.

340350360370380390400410420430460480500520540560580600620640660reach (mm) →↑ stack (mm)44495254565861

Character of each size

Compared with other road bikes. Further right means more of that quality.

44
49
52
54
56
58
61
Positionracing → relaxed
Steeringcalm → quick
Pedallingrearward → forward
Bottom brackethigh → low
Wheelbaselively → planted
Rear endstable → agile

Bikes with similar geometry (size 54)

The closest size of other road models, by stack and reach.

ModelΔ stackΔ reach
Specialized S-Works Tarmac SL9 · 542026±0 mm±0 mmCompare →
Specialized Tarmac SL9 S-Level · 542026±0 mm±0 mmCompare →
Specialized Tarmac SL9 · 542026±0 mm±0 mmCompare →
Cube Agree C:62 · 53 cm2026±0 mm−1 mmCompare →
Cube Agree C:62 SLX · 53 cm2026±0 mm−1 mmCompare →
Cube Agree C:62 EX · 53 cm2026±0 mm−1 mmCompare →
Tarmac SL8 or S-Works Tarmac SL9? In size 54 they have exactly the same stack and reach (544 / 384 mm): the difference is in the frame and build, not the position.

Frequently asked questions

What size Tarmac SL8 do I need?

It depends on your position, not just your height. The most reliable way is to compare the stack and reach of a bike that fits you with those of each size (from 501/366 mm in size 44 to 612/408 mm in size 61). The size finder on this page shows the closest size and the stem and spacers you would need.

What are the stack and reach of the Tarmac SL8 in size 54?

Stack of 544 mm and reach of 384 mm, with an effective top tube of 541 mm and a head angle of 73.0°.

Is the Tarmac SL8 a racing or an endurance bike?

In between. In size 54 its stack-to-reach ratio is at percentile 35 of road bikes: neither very low nor very tall.

Does it have the same geometry as the S-Works Tarmac SL9?

In size 54, yes: same stack and reach. If one already fits you, the same size of the other will put you in the same position.