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  • Syntace P6 Carbon HiFlex
  • Syntace P6 Carbon HiFlex Detail
  • Syntace P6 Carbon HiFlex Detail
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SyntaceP6 Carbon HiFlex
Sale 32% Off$182.92 - $203.52

Item # SYN000A

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  • One Color, 27.2/400mm ($203.52)
  • One Color, 31.6/400mm ($182.92)
  • One Color, 30.9/400mm ($185.41)
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Item # SYN000A

Smoothing the ruts.

Syntace's P6 Carbon HiFlex is not a shock absorbing seatpost. It is a carbon seatpost that is designed to gently dampen the effects of rough roads or rutted trails, which, in turn, lets you focus on using your legs to put power to the pedals.

For the P6, Syntace arranged carbon fibers in such a manner that the seatpost is able to flex backwards under load, which increases a rider's comfort without any sideways movement. The benefit is that the post takes the edge off of the bumps on your road bike. If you're on your mountain bike, conventional seatposts and saddles force you to lift your weight slightly from the perch to minimize bumps. This means you're hovering instead of standing or sitting, which is a tiring position to ride in. Using the P6 HiFlex, however, you're able to remain seated over ruts in the trail, letting your legs push the pedals rather than holding you off the saddle.

The HiFlex also features an integrated carbon head. It uses cold-forged alloy (7075) lower rail plates and deep-head titanium bolts to give 30 degrees of saddle tilt, plus maximum rail support.

The Syntace P6 Carbon HiFlex is available in the sizes 27.2/400mm, 30.9/300mm, 30.9/400mm, 31.6/300mm, 31.6/400mm, and 34.9/480mm.

  • Integrated carbon head
  • Cold-forged alloy (7075) lower rail plates and deep-head titanium bolts
  • 30 degrees of saddle tilt
Tech SpecsWeight
Tech Specs
carbon fiber
27.2 mm, 30.9 mm, 31.6 mm, 34.9 mm
[27.2] 400 mm, [30.9] 300 mm, [30.9] 400 mm, [31.6] 300 mm, [31.6] 400 mm, [34.9] 480 mm
Manufacturer Warranty
1 year
Recommended Use
mountain, road

Actual Weight

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

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One Color, 27.2/400mm
One Color, 31.6/400mm
One Color, 30.9/400mm

Claimed Weight

Claimed weights are provided by the vendor.

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[27.2] 231 g, [30.9] 220 g, [31.6] 220 g, [34.9] 238 g

Reviews & Community


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Unanswered Question

Does this seatpost have any offset? I know the bottom clamp is extended on one side, but I can't tell if the top clamp is centered or offset.


  • Familiarity: I've used it several times

This is an awesome seatpost. Sure, it is relatively light. But, that is not why I bought it. I bought it for comfort. A word about comfort. If you look across the web, the only negative reviews of the Syntace P6 say something like, “This thing doesn’t live up to its claims (note: what claims?); it doesn’t have as much compliance as my Thudbuster.” Or, “I couldn’t bend in my hands.” Or, “I sat on it and I couldn’t feel it move.”. Well... those are silly comments. This is not an active suspension seatpost. It is a wonderfully designed, wonderfully manufactured compliant seatpost.

I bought this to replace a Fizik Cyrano R5, which is also an excellent, very light seatpost. But, in 31.6 diameter that I needed, it was just too harsh. On another bike, I have a 27.2, which is pretty nice.

By comparison, the Syntace, also a 31.6, is a revelation. The vibration from crappy, pebbly blacktop just disappears. Descending a steep bridge with metal “tent” covers over the compression joints I was no longer propelled off the saddle like I was before.

Of course you can feel bumps. When the road goes up, the bike must go up, and the person on the bike must go up. The harsh jolt is gone. The up is damped and lessened considerably. Compared to an alloy post, you can just sit (if you want to); you don’t have to unweight by semi-standing on the pedals in anticipation.

I have never had any other carbon seatpost so I can’t compare it to others. The Syntace is wonderfully finished. It is light, but not the very lightest—you don’t want it to be. You want it to be safe and reliable as well as light and comfortable. The head is NOT bonded on as some reviews state: it is part of the carbon layup, but it is solid carbon. Syntace says max bolt force on the head bolts is 8nm. I used a 5nm torque wrench and didn’t get all the way to the click at 5. The seat does not move. It absolutely does not ping or creak. It is easy to adjust saddle tilt (I am a leetle OCD about saddle tilt). It as easy to make tiny, precise adjustments—and big ones if you need to.

This is just a really great product.

Mfgr offers a 10 year warranty, not 1 year as stated incorrectly in Competitive Cyclist’s description above.

Will this post fit with my ergon SR saddle, which has 7x9 Carbon rails? Thank you.

Hi Martin, this will indeed fit carbon railed saddles.

Perfect Hardtail Companion

  • Familiarity: I've used it several times

I was a little bit skeptical about the claimed "absorption" of this post, but it did not disappoint me!

Out of the package you can tell that the quality of this post is up to any carbon post on the market. I paired this post of with an Selle SMP Dynamic saddle and the body appreciates the added comfort from both saddle and post.

I would highly recommend this post to anyone doing some gravel riding, to XC riding.

If you have questions about this post or other brands feel free to reach out to me.

Perfect Hardtail Companion

A truly great seatpost

  • Familiarity: I've put it through the wringer

There is no mistaking this seat post for anything other than what it is: a lightweight carbon fiber post. There is also no mistaking the significant flex and compliance that you can see and feel when riding. I ride a 29

Carbon Fiber At Its Best

  • Familiarity: I've used it several times

Carbon fiber has gained traction in the bike industry because of its stiffness to weight ratio and wide variety of different applications. This seatpost is a perfect example of how carbon fiber can be engineered to be effective in a multitude of different ways.

The post feels solid, but flexes a bit to provide some compliance. This technology would likely work just as well on a road bike, but I have it on my full suspension MTB and it seems to take quite a bit of sting out of the ride. If you're looking for a post that cuts some of the roughness out of your ride, the search stops here.

Get in touch with me if you have any questions about this post or what you'd use it for/if it would be appropriate for your custom build.

How much of the post needs to be exposed in order to get the full benefit of chatter reduction?

Will this post fit with my fizik arione 00 saddle, which has 7x9 Carbon rails? Thank you.

Hey John, yes, this will work. It uses clamps on top and bottom of the rails (not on the sides) so it isn't rail size specific. It will accommodate round rails, as well, should you decide to switch down the road. Send over an email to if you have more questions.

Unanswered Question

Wondering if there's much merit to this seatpost on a full squishy. I have the 2015 Epic S-Works, with the brain front & back. Brain recognizes the big stuff, but is supposed to act like an HT when the terrain doesn't require the shock to engage. Hence the question - any known users of this seatpost find benefit on their full squishies?

Avg. ride time: 11h 21m per week
  • Average ride time is based on Strava activity over the last 3 months. Give your reviews credibility by connecting your account.

Is the 30.9 seatpost compatible with an internal seatpost di2 battery?

Thank you. If I am installing this on my titanium frame, do I need to use any lube/silicone spray/carbon paste?

Works as advertised--comfy

  • Familiarity: I've put it through the wringer

I replaced an aluminum Deda seatpost with this one. The post has an asymmetrical carbon layup (see photo) that creates a smooth shock absorbing characteristic without robbing you of power. I use this post on my Seven cross bike for my daily commute (35 miles). Truly sensational piece of gear.

Works as advertised--comfy

No 27.2?

According to the description, 27.2 400mm is available. I just took delivery of one from Competitive Cyclist yesterday.