Prime Kanza Gravel Seatpost

Prime's Kanza Inline Gravel Seatpost is a durable, affordable alloy option for both road and gravel bikes. The clamp makes adjustments really easy, but the claimed anti-shock effects are questionable – personally I couldn't detect any difference between this and a regular aluminium post. Nevertheless, it's still decent value and otherwise effective.

The Kanza is available in either a 27.2mm diameter or 31.6mm, and a single 350mm length. Some might consider the lack of a 30.9 a bit disappointing. Even with the weight-saving, elliptical cross-section it tips the scales at 314g, which is slightly heavier than both Zipp's Service Course (290g) and Ritchey's Classic Two Bolt at 260g.

The forged alloy is a decent grade, namely 2014-T6 – the same as the Ritchey uses – while the all-black design and subtle logos make for a good look on any bike. It looks more expensive than it actually is.

For me, the best feature is the simple adjustment. Two 5mm bolts adjust the fore-aft position and the tilt, and with one bolt on the underside and one on the right, they are really easy to access. For the position-obsessed riders out there, it's a good system.

On the downside, there are no height alignment marks on the post itself... a negative for the position obsessed, then.

Shock and... awww

Prime doesn't feature this post on its website and the stockists (Prime is a Wiggle/CRC brand) don't publish any meaningful details about the anti-shock technology.

Taking the post apart reveals this tech comes in the form of a rubber bush in the clamp. More technically, it's an isolastic decoupling system – nothing groundbreaking, then, given that Norton used a similar thing to dampen vibes in the 1960s.

Once I'd extracted the central element I clamped its inner section in a vice and, using adjustable grips, attempted to rotate the outer to get a feel for how compliant the rubber is. With a hell of a lot of force I was able to see something like the claimed four degrees of movement. So yes, the anti-shock technology is completely legit.

Bad vibes

However, out in the real world I couldn't feel any benefit since any residual vibrations not dampened by my tyres, wheels, frame and even the saddle and its rails don't seem to be of significant magnitude to activate the rubber bush.

For the record, I tried this on a gravel bike with 47mm 650b tyres at 40-50psi, and on my road bike with 36mm tyres at 60psi. Both are tubeless.

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If anyone out there has one of these posts, is running skinny tyres at a much higher pressure, and is significantly heavier than an average rider, I'd be keen to hear your thoughts.

With a de-coupling system like this there is also a theoretical possibility of loss of power. Given the effort necessary to activate it at all, I'd say any losses are miniscule.

Value

In short, if you're looking to tangibly boost your comfort levels you could better invest in some wider tyres and run them at lower pressures – or perhaps just get an accurate, digital pressure gauge such as the Topeak Smart Gauge D2. Many track pumps won't register an accurate pressure.

At £40 the Kanza is a reasonable price for a well-made alloy post, even ignoring the shock absorption idea. Zipp's Service Course Seatpost is £50, for instance, with no extra tech to offer.

If you simply want a no-frills, inline post though, something like the Brand-X Inline 6061 is just £16.99.

Conclusion

The Prime Kanza Inline Seatpost would make a decent addition to a self-build road/touring project. While I personally didn't feel the benefit of the anti-shock technology, it clearly exists. Put this aspect to one side, though, and you are still getting a robust, smart looking, well-engineered seatpost for your money.

Verdict

Well-made, smart looking post, but anti-shock tech is unlikely to be felt by either road or gravel riders