First Look: Crankbrothers Kronolog Height-Adjustable Seatpost

Crankbrothers has been in the adjustable post game for five years, and during that time they've learned what works and what doesn't. Inspired by the simplicity of a bar clamp, the kronolog seatpost is their new, radically simpler solution.

The kronolog has been in development for two years. Design, prototype, test, repeat (about 10 times). The result is this beauty. It's an air sprung, mechanically actuated, height-adjustable seatpost with five inches of travel.

Prototype number one on the left, refined rapid prototype on the right. Crankbrothers uses a 3D printer daily to validate designs, which speeds up the process greatly. In the audio, Clark Brewster fills us in on where it all started.

What sets the kronolog apart from others? Several things. First, it's the only mechanical post that is infinitely adjustable. The post will remain stationary at any point between full extension and slammed.

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The kronolog in action.

A simple set of plates lock the post into place, both up and down. They hold the post similar to the way a bar clamp works, but in both directions. When locked, the plates are at an angle relative to the post. Note the silver area that runs along the post. The ano has been removed here, which improves grip.

When the cable is pulled, the plates come together, perpendicular to the post, which allows it to move up and down freely. A removable cap snaps into place to prevent dust, dirt, and water intrusion. During testing, they rode them without the caps with no issue after several thousand cycles of use.

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A large spring is constantly pushing the plates apart. This creates the angle needed to hold the post securely, and it also keeps the cable tight.

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It doesn't budge...

To simultaneously adjust the rebound speed and force required to push the post down, simply attach a shock pump to the bottom of the post. Pressure changes (from 55-75psi) are pretty noticeable, so be sure to bring a pump when flying to higher altitudes.

The air system is sealed internally using o-rings. The piston itself remains stationary while the upper portion of the post comes down around it. The post rebounds in two stages - fast at first then slow at the end - due to a tiny hole in the piston plunger.

This bushing is crucial to the system. Crankbrothers individually matches bushings to posts to ensure that every post feels the same. If they didn't, posts might rebound differently or there might be unwanted play in the system.

Combined with the properly fitted bushing and flat sides on the upper portion of the post, the internal key system eliminates rotational play. Say goodbye to wiggly seats. This thing is solid.

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It does twist slightly, but it's a snug fit with no play.

It is possible to reduce the amount of adjustment on the kronolog. While the system is apart (which is fairly easy to do), simply snap a spacer onto the main piston. A 20mm spacer comes with the post and it can be trimmed to any length desired.

Simple. Clean. Crankbrothers.

The kronolog is available in both 30.9 and 31.6mm diameters, and a 27.2mm version is in the works. The post measures 405mm long and weighs 465 grams. For those counting, that's 50 grams less than the Joplin.

A 3D forged quill mates up with the seat clamp, which is available in gold, blue, orange, red, or black, as is the lever.

Chad Peterson bombs into one of the gnarlier shoots in Laguna knowing that the post he helped bring to life can withstand 270,000 g-outs. That's 2.7 times the number required by EN fatigue testing standards.

Top, bottom, left, or right... the lever can be mounted anywhere you want it. It's thin enough that it doesn't clutter the bars or interfere with brakes or shifters.

Here's another big plus. Stationary cable routing. My bike got quieter and cleaner in one swoop. As you can see here, it's possible to run the cable to the front or back of the post.

Hans Rey has been an integral piece of the Crankbrothers development team for several years, and he played a big part in how the kronolog turned out.

Hans put a lot of time on each version of the post before giving his final approval.

Is an adjustable post worth it? Hans doesn't know how he'd ride without one anymore. With just a push of a button, he and Richey Schley cruise down the trail with their seats slammed.

Thanks for the reminder, Ritchey. He also had a lot of input on the kronolog, as did Chris Van Dine, Jill Kintner, Bryn Atkinson, and many more.

The system uses shifter cable in brake housing. Why? It allows a bit more flexibility than shifter housing, which helps prevent unwanted engagements. The lever is easy to press and there is a distinct feel when the post comes free.

Along the same lines of the brake housing, it's important to set the post up with a smooth bend in the housing and a little slack in the cable to prevent accidental engagement. Easy enough.

Is there a drawback? Here's one, but it'll only affect a few people. If the distance between the top of your seat clamp and the center of your seat rails measures less than 8.75 inches, you'll need to install a spacer internally, which will reduce the amount of travel. The overall height is a full inch taller than the Rock Shox Reverb.

Crankbrothers is claiming that "the kronolog sets a new standard for adjustable seatposts." It certainly combines all the best features into one package, is simple yet precise, easy to maintain, highly adjustable, and feels bombproof. Well done. We'll continue to test it and let you know if that changes.

It's no Schleybletop, but it'll do as a parting shot. Crankbrothers, thanks for a fun day on an exciting new product with a couple of legends!

First Look: Crankbrothers Kronolog Height-Adjustable Seatpost

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