- 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 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.
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
- Size guide and geometry for the Specialized Roubaix SL8
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
- 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
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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