Between the ever-larger frame tubes (on road and off) and the proliferation of dropper posts (for the latter), it sometimes seems as though the humble 27.2mm seatpost is headed for extinction.  This isn’t necessarily a bad thing- larger diameter tubes are less likely to bend and require less clamping force to stay put.  They’re also… stiffer.  And, for lighter riders or those looking for a bit of comfort in their rides, this can be a shame.  My recent replacement of a scandium-framed single speed (with nearly a foot of 27.2 carbon swaying in the breeze) with an aluminum frame and 30.9 seatpost had my pampered backside and spine wondering what they’d done to deserve the sudden abuse.

Which is why I jumped at the opportunity to give Syntace’s new P6 Carbon HiFlex seatpost a try.  Taking the company’s proven P6 head and adding a shaft with twice the shock absorption of its predecessor, the P6 Carbon HiFlex boastings “improved oscillation dampening and directional stability even when drifting around corners or when hitting harsh ruts.” Indeed, a flexy post sounded like just the solution.  Hit the jump for more details, more photos, and a couple of initial impressions…

The P6’s reversible lower rail cradle is a full 52mm long, providing a good deal of support for lightweight saddles or odd riding positions.  At the same time, a 30mm cradle top maintains good fore-aft adjustability. Two M5 (hooray!) bolts make for easy and solid adjustment- a claimed 30 degrees’ worth (Maverick owners take note).

Despite a substantial clamp and adult-sized hardware, our 30.9x400mm post came in at 220g (213g advertised).  For comparison, that’s 45g lighter than a 30.9x410mm Thomson Elite.  The Syntace’s unidirectional carbon tube is thicker at the front and back than on the sides.

With only two hours on the P6 Carbon HiFlex, I will say that the post is immediately more comfortable than the Ritchey WCS or USE Sumo carbon seatposts that had been on the bike in the past.  Although it is possible to see some movement when bouncing on a stationary bike, the actual motion is much more subtle- it just makes the bike feel nicer.  Fitted with a bit of Tacx assembly paste in the seat tube, the Syntace has yet to make a peep, and I was happy to find that there’s plenty of clearance for easy on-trail adjustment using a mini tool.

While I initially worried that the $220 asking price would be hard to justify, it is not out of line with other high-end carbon posts and-more importantly-has really rekindled my enthusiasm for what had been a pretty uncomfortable ride.  Look for an in-depth review this fall…



  1. The only problem is they seem unobtainable. I have never found one in stock or been able to get one easily from my LBS.

  2. Cale,
    I use the Elite as a yardstick because they’re everywhere and everyone seems to have owned one. It’s probably the most common post out there- not too heavy, not too light, not too weak or strong.

    QBP are stocking them now, which should mean that your favorite shop can get them. Otherwise, try the distributors at


  3. i been on a hiflex for almost a year now. i had to wait months for backorder ,but it is the best bike component i have bought in ten years. it makes my hardtail so supple i rarely ride my dually.

  4. Fortunately I live in Europe where Syntace is very obtainable :). I use exactly the same seatpost (30.9x400mm) on my carbon Epic. I am very happy with is and it is very goodlooking too. When I asked Syntace about carbon assembly paste, they advised to NOT use any. Just clean the seattube on the inside was all.
    “If you will changing the position of the seat post sometimes it isn’t good to use assembly paste. The surface can get scratched. Especially in a carbon frame the P6 carbon seat post will stay in place without using assembly paste too.”

What do you think?