- Argon 18 Nitrogen Pro
- XXS
- Stack 486, Reach 370
- Specialized Tarmac SL9
- 44
- Stack 501, Reach 366
Stack: 15 mm taller
Reach: 4 mm shorter
Argon 18 Nitrogen Pro 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 are close, a few millimetres apart. The frame alone will not decide this; use your measurements to see which size and setup gets nearer to your position on each bike.
In one look
Argon 18 Nitrogen Pro: race geometry. Specialized Tarmac SL9: race geometry.
- The frame front of Specialized Tarmac SL9 is slightly higher, by about 8 mm. That difference alone does not settle your position.
- The forward length of the frame is nearly the same across matched sizes.
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
Both start at a similar price level, going by the cheapest build you can buy of each.
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.
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
The matched frame measurements differ by only a few millimetres, so stem and spacer choices can matter more than the frame.
Typical difference across matched sizes: frame front height 8 mm, forward length 1 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 Argon 18 Nitrogen Pro and Specialized Tarmac SL9 sizes compare?
See the closest size matches and the differences in stack, reach, and riding position.
- Argon 18 Nitrogen Pro
- XS
- Stack 508, Reach 377
- Specialized Tarmac SL9
- 49
- Stack 514, Reach 375
Stack: 6 mm taller
Reach: practically identical
- Argon 18 Nitrogen Pro
- S
- Stack 531, Reach 384
- Specialized Tarmac SL9
- 52
- Stack 527, Reach 380
Stack: 4 mm lower
Reach: 4 mm shorter
- Argon 18 Nitrogen Pro
- M
- Stack 555, Reach 392
- Specialized Tarmac SL9
- 56
- Stack 565, Reach 395
Stack: 10 mm taller
Reach: 3 mm longer
- Argon 18 Nitrogen Pro
- L
- Stack 580, Reach 400
- Specialized Tarmac SL9
- 58
- Stack 591, Reach 402
Stack: 11 mm taller
Reach: practically identical
- Argon 18 Nitrogen Pro
- XL
- Stack 607, Reach 409
- Specialized Tarmac SL9
- 61
- Stack 612, Reach 408
Stack: 5 mm taller
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: Argon 18 Nitrogen Pro or Specialized Tarmac SL9?
- The frame front of Specialized Tarmac SL9 is slightly higher, by about 8 mm. That difference alone does not settle your position.
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