It will only take one ride on a Niner RDO Carbon Seatpost for you to feel the difference. Whether your ride a hardtail or a full-suspension bike, you'll notice less fatigue at the end of that ride thanks to what Niner calls the 'unstiff' carbon layup. Niner states that its monocoque design deflects up to twice as much as other leading carbon posts; in fact, it'll deflect 8.2mm under a 50kg load. For comparison's sake, Niner's standard-issue carbon posts deflects 6.3mm under the same load.Unlike other posts that use bonding to join disparate materials, the RDO (Race Day Optimized) post is molded into a single, structurally superior shaft. Niner varies wall thickness and the carbon weave to offer the strength needed, but tunes it to flex so as to allow the post to dampen fatiguing buzz. A simple-to-adjust, two-bolt clamp ensures you'll quickly dial in the perfect saddle position, and it features an alloy head for durability.The Niner RDO Carbon Seatpost is a zero-offset post and comes in 27.2, 30.9, and 31.6mm diameters. The 30.9 post is 370mm long, while the 27.2 and 31.6 posts are 400mm. The post comes with graphics that complement Niner's frames; Green, Moondust, Tangerine, and Red.
Strengths: Definitely soaks up trail chatter on my hardtail 29er. Lightweight. Looks great.
Weaknesses: Ain't cheap.
I bought this to help my back/body so that I can continue to enjoy my aluminum HT..it worked. You can see/feel the flex fore/aft, but its not un-nerving. Just seems to deaden the vibrations/hits so that I can stay in the saddle a bit more over roots etc.
Strengths: Really soaks up trail chatter... Makes a significant difference on my hard tail 29er; my back thanks it for it on every ride. Also aesthetically, this post is a 10. One of the nicest unidirectional carbon layups I've seen. No slippage.
Weaknesses: Expensive. But for hard tails, worth it.
Niner advertises this post as having an 'unstiff' layup with a much greater deflection than most post, and it is absolutely noticeable. You can see the flex when you install it. It really transformed by Niner Air 9 Carbon's ride... I had previously a Thomson Masterpiece post in the frame, and the difference ride-feel between the two is night and day.
It isn't the bad kind of 'flexy' either -- no impact on the power transfer, as the lateral stiffness of the frame is not impacted at all.
That said, you would not need this post UNLESS you were riding hard tail. And if your frame is already compliant on the trails, it might be overkill. That said, if you are riding a stiff XC race oriented carbon or aluminum frame, this post could totally be the back-saver that revives your joy of your bike.
This is really one of the best carbon seat post expecially for a rigid bike. I ride a rigid ss and the RDO carbon gives you a flex that gives you the extra cushion you need on a rigid bike. A+ in my book