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FSA SL-K Carbon ITC Seatpost SB20/-10

Sale $81.90$124.99 34% Off

Item # FSA001I

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  • Black Logo, 31.6mm, 350mm ($81.90)
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Item # FSA001I


Clamp on a smarter clamp.

Bikes have evolved rapidly over the last few decades, but one area of engineering that's been slow to change much is that which can cause the biggest headaches: seatpost clamps. Thankfully, some of the sharpest minds in cycling components have dreamt up, and realized, a mighty fine solution: the FSA SL-K Carbon ITC SB20/-10 Seatpost.

The SL-K family of components from FSA is premium gear that somewhat undercuts the prices of the company's top-line K-Force components. As such, the SL-K post is made of unidirectional carbon fiber, keeping weight down and making the post able to absorb a bit of shock from your ride. At the top of the post, however, is where the real brains come in. FSA's new ITC (Independent Top Clamp) design not only makes popping the saddle on and off the post very easy, it also allows for independent adjustment of the saddle's angle and position. Further, the clamps' side plates can be easily repositioned to toggle between two different offsets: -10mm or 20mm.

The FSA SL-K Carbon ITC SB20/-10 Seatpost comes with two different logo finishes — either Red or Black — and in 31.6mm or 27.2mm diameters. All versions are 350mm in length, and the post is appropriate for either road or mountain biking.

  • Unidirectional carbon fiber
  • Independent Top Clamp
  • Convenient, independent adjustment of the saddle’s angle and position
  • Toggle between two different offset: -10mm or 20mm

Tech Specs

[shaft] UD carbon, [head] bonded alloy
27.2 mm, 31.6 mm
350 mm
20/-10 mm
Recommended Use:
road cycling, mountain biking
Manufacturer Warranty:
2 years



Actual Weight

Actual weights are measured in-house by the Competitive Cyclist team.

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Black Logo, 31.6mm, 350mm

Claimed Weight

Claimed weights are provided by the vendor.

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[27.2mm] 230 g

Reviews & Community


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Unfulfilled promises...

  • Familiarity: I returned this product before using it

I specifically bought this as a lower cost alternative to use the -10mm offset on my Specialized Tarmac. I cannot fault the quality of the workmanship as it appears straight out of the box. Unfortunately, I placed the order prior to the review by Danny M H being posted.
Sadly , the saddle cannot even be set horozontally on my bike, either, in the -10mm offset position! It's pointing up!
By the looks of it, it could have easily been engineered to allow for more adjustability. And, I'm very surprised hat neither FSA nor Competitive Cyclist made note of this restriction in the description or technical specs.
If you intend to use the -10mm offset, please be sure your seatpost is nearly straight up, at least 78 degrees or so, or you're going to be disappointed & will be returning this seatpost!

Not able to use the -10mm offset

  • Familiarity: I returned this product before using it

First off, this seat post is beautiful, light and seems to be built very well. I got this for a Kestrel Legend road bike so that I can use the forward offset to switch the geometry a bit for triathlons. Unfortunately, my seat tube angle is 73.0 degrees and with the -10mm offset my saddle sits just barely (5 degrees or less) above horizontal and that is enough to put pressure on my perineum. I hate to do it but am returning this seat post.

This seems like a great seatpost but if you plan on using the -10mm offset make sure your seat tube angle is greater than 73.0 and/or your saddle rails are slightly less than horizontal to compensate.

Unfortunately, I have to return this seatpost for the same problem. I wanted to use the -10mm offset, hiwever, on my Specialized Tarmac, the saddle cannot even be set horozontally. It's pointing up!

If you intend to use the -10mm offset, please be sure your seatpost is nearly straight up, at least 78 degrees or so, or you're going to be disappointed & will be returning this seatpost!

Unanswered Question

will this seatpost work with 7x9 saddle rails?

Best seatpost I've ever used

  • Familiarity: I've put it through the wringer

This is an excellent, no nonsense seatpost. I ride Sella SMP’s. Due to their rail design they are devilish hard to keep from sliding backward over time on most seatposts. This seatpost, with 8.6nm clamping force ON EACH SIDE provides plenty of holding power. My SMP’s have remained as solid as a rock, even in hard racing conditions. Also, having never used a seatpost with a single bolt to hold the saddle angle I was skeptical; no need, that’s been rock solid too. Last but not least, I was also very pleasantly surprised to find that the ITC makes saddle adjustments extremely easy. Far easier and faster than any other post I’ve ever used. I highly recommend this seatpost.

Works for Me

  • Familiarity: I've used it several times

I chose this seat post for my Ridley build. There where no issues with installation or quality of the seat post, and it's been perfect so far on my three rides.

Works for Me
Avg. ride time: 10h 46m per week
  • Average ride time is based on Strava activity over the last 3 months. Give your reviews credibility by connecting your account.

Just what I needed...

  • Familiarity: I've used it once or twice and have initial impressions

I recently had my bike professionally fitted, and I went with a new saddle that ended up making for a sore bum. After a few weeks of trying to wear it in, I decided to go back to my original Selle Italia.

One problem... the seat wouldn't allow enough adjustment, so it was set back 15mm too far.

This seatpost has a 20 or -10 offset, so it solved my problem. It is pretty inexpensive for carbon, but it feels pretty good, and looks well made. Hey, as long as the saddle is on the post, I am happy.

Just what I needed...