Can the same rider take different sizes on these two bikes?

Yes. Frame labels are not standardized, so the same rider may need different sizes. This comparison deliberately avoids a generic matched-size answer and hands your measurements to Bike Fit instead.

Which frame has the higher front: Specialized Roubaix SL8 or Specialized Tarmac SL9?

Across matched sizes, the frame fronts of Specialized Roubaix SL8 and Specialized Tarmac SL9 differ by only a few millimetres. Stem and spacer choices will have more effect on handlebar position.

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Specialized Roubaix SL8 vs Specialized Tarmac SL9: which bike is right for you?

Compare ride character, intended rider, geometry, and fit. Add your measurements to see which bike suits you better and which size to choose on each.

Fit verdict: the frame positions differ enough to matter. Compare the geometry below, then use your measurements to identify the safer size and setup.

Compare them for me Compare geometry and sizes

In one look

Specialized Roubaix SL8: endurance geometry. Specialized Tarmac SL9: race geometry.

Across matched sizes, the frame fronts of Specialized Roubaix SL8 and Specialized Tarmac SL9 differ by only a few millimetres. Stem and spacer choices will have more effect on handlebar position.
The frame front of Specialized Tarmac SL9 is about 20 mm longer. Handlebar position also depends on the stem and spacers.

For the Specialized Roubaix SL8 in 61, 64 there is no Specialized Tarmac SL9 size with a comparable position: the range simply does not reach there.

The frame standards line up and we hold no sourced weight or performance claim that separates them. What is left to decide is your size and setup on each frame.

Price
Specialized Tarmac SL9 is the dearer of the two, going by the cheapest build you can buy of each; Specialized Roubaix SL8 starts lower.

Subjective findings from independent tests on stock or near-stock builds. Tyres, pressure and size change how a frame feels.

We compare differences at frame and model level. Components, current price, and availability depend on the exact build and seller.

2025 • endurance geometry: Specialized Roubaix SL8; Full size guide
2026 • race geometry: Specialized Tarmac SL9; Full size guide

What do you need from this comparison?

Start with the decision you are making. We will ask only for the details needed to answer it.

Step 1/1

What are you trying to understand?

Your answer decides which questions follow and what the result focuses on.

Fit and size differences

Geometry can separate these bikes: matched sizes create a meaningfully different position.

Typical difference across matched sizes: frame front height 3 mm, forward length 20 mm.

For a personal answer, the fit-and-size path uses your measurements to show only the relevant frame sizes. The full chart remains available as a reference.

View geometry for every size

How do Specialized Roubaix SL8 and Specialized Tarmac SL9 sizes compare?

See the closest size matches and the differences in stack, reach, and riding position.

Specialized Roubaix SL8: 44; Stack 543, Reach 353
Specialized Tarmac SL9: 54; Stack 544, Reach 384

Stack: practically identical

Reach: 31 mm longer

Specialized Roubaix SL8: 49; Stack 549, Reach 363
Specialized Tarmac SL9: 54; Stack 544, Reach 384

Stack: 5 mm lower

Reach: 21 mm longer

Specialized Roubaix SL8: 52; Stack 566, Reach 370
Specialized Tarmac SL9: 56; Stack 565, Reach 395

Stack: practically identical

Reach: 25 mm longer

Specialized Roubaix SL8: 54; Stack 585, Reach 381
Specialized Tarmac SL9: 58; Stack 591, Reach 402

Stack: 6 mm taller

Reach: 21 mm longer

Specialized Roubaix SL8: 56; Stack 605, Reach 389
Specialized Tarmac SL9: 61; Stack 612, Reach 408

Stack: 7 mm taller

Reach: 19 mm longer

Specialized Roubaix SL8: 58; Stack 630, Reach 397
Specialized Tarmac SL9: 61; Stack 612, Reach 408

Stack: 18 mm lower

Reach: 11 mm longer

Specialized Roubaix SL8: 61; Stack 665, Reach 403
Specialized Tarmac SL9: 61; Stack 612, Reach 408

Different position

Stack: 53 mm lower

Reach: 5 mm longer

Specialized Roubaix SL8: 64; Stack 685, Reach 409
Specialized Tarmac SL9: 61; Stack 612, Reach 408

Different position

Stack: 73 mm lower

Reach: practically identical

Specialized Roubaix SL8	Specialized Tarmac SL9	The position will feel
44Stack 543 · Reach 353	54Stack 544 · Reach 384	Stack: practically identical · Reach: 31 mm longer
49Stack 549 · Reach 363	54Stack 544 · Reach 384	Stack: 5 mm lower · Reach: 21 mm longer
52Stack 566 · Reach 370	56Stack 565 · Reach 395	Stack: practically identical · Reach: 25 mm longer
54Stack 585 · Reach 381	58Stack 591 · Reach 402	Stack: 6 mm taller · Reach: 21 mm longer
56Stack 605 · Reach 389	61Stack 612 · Reach 408	Stack: 7 mm taller · Reach: 19 mm longer
58Stack 630 · Reach 397	61Stack 612 · Reach 408	Stack: 18 mm lower · Reach: 11 mm longer
61Stack 665 · Reach 403	61Stack 612 · Reach 408	Different position
64Stack 685 · Reach 409	61Stack 612 · Reach 408	Different position

The same size label can create a different position on each frame. Stack and reach are one part of the decision; the personalized comparison connects them to your body and each bike’s ride character.

FAQ

Can the same rider take different sizes on these two bikes?: Yes. Frame labels are not standardized, so the same rider may need different sizes. This comparison deliberately avoids a generic matched-size answer and hands your measurements to Bike Fit instead.
Which frame has the higher front: Specialized Roubaix SL8 or Specialized Tarmac SL9?: Across matched sizes, the frame fronts of Specialized Roubaix SL8 and Specialized Tarmac SL9 differ by only a few millimetres. Stem and spacer choices will have more effect on handlebar position.

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