First Date: Crank Brothers Kronolog

Dropper seatposts (or uppy-downy posts as the Brits like to call them) are definitely my favourite new mountain bike products of the last several years. What else has that big of an impact on your ride? I’ve used a few different dropper posts, and they’re a fixture on every trail or AM bike I ride – whether it’s a test bike or my personal steed.

Dropper posts have been around in one form or another for almost a decade. The Gravity Dropper, introduced in 2003, was one of the earliest dropper posts, followed a few years later by Maverick’s Speedball post in about 2006. Maverick ended up licensing its 4” mechanical (cable-activated) design to component manufacturers Crank Brothers, who made some minor tweaks and re-named it the Joplin. The Joplin found its way on to quite a few bikes, but it wasn’t exactly a shining example of a well-executed aftermarket product. To say that the Joplin had some reliability and performance issues would be polite…

The folks at Crank Brothers knew that the Joplin had shortcomings, but instead of trying to re-engineer that post, they threw the baby out with the bath water and started from scratch. The result was a brand-new dropper post from Crank Brothers: the Kronolog.

The new Crank Brothers Kronolog post, from the side. The height-adjustable mechanism is under the silver cap in the centre of the post. This is one seriously slick post.

The Kronolog is a mechanically-activated, air-sprung post that – in simple terms – uses two metal locking plates with a small coil spring between them to control up and down movement. When the cable is pulled, the plates are pulled together, the spring that holds them apart is compressed and the post is unlocked so it can move up or down. Rider weight compresses the post, and the air spring raises it back up. Then the plates are in the locked position, and the post doesn’t move up or down.

The post uses two-stage air damping to control the return rate, meaning it’s faster initially and then slows down for the last portion of the travel; return rate is controlled via an air valve at the bottom of the post. Air pressure range is from 50 to 100 psi, with higher pressures delivering faster return rates.

Kronolog posts measure in at 405mm long, with a claimed weight of 465g for a 30.9mm post and 28g for the remote. 31.6mm posts are also available and word on the street says that a 27.2mm version is in the works. You get 125mm / 5” of infinitely adjustable up and down, but you can throw in a 20mm spacer if you want to limit travel for some reason. Standard colour options are black and red or black and black, but it’s also possible to get aftermarket Kronolog clamp and lever colour kits in gold, blue or orange to colour-coordinate with your bar end caps / spoke nipples / headset spacers.

The Kronolog’s height adjusting mechanism, with the protective cover removed. The locking plates are the two silver pieces of metal coming out of the post. The entire assembly seems to be well protected from the elements, but time will tell how it stands up to the Shore.

The Kronolog’s cable is routed in through the bottom of the plate-and-spring mechanism (which is covered to protect the mechanism from the elements), rather than being attached at the top of the post near the saddle clamp as it is on most other dropper posts. Because it’s connected to the fixed part of the post, cable length doesn’t change along with saddle height. It’s possible to set the post up with the mechanism facing the front or back of your bike, depending on your preference and cable routing on your ride.

The post comes with a two-year warranty with “proper maintenance,” whatever that means; I’ll get the official word for the full review. Hopefully, there’s not a lot required – I don’t mind doing some maintenance, but don’t want to be tearing things apart regularly. MSRP on the Kronolog is US$300; check your LBS on this side of the 49th parallel for Canuck pricing, but be prepared for some sticker shock.

Some initial observations
The Kronolog comes out of its fancy box all ready to fly and it looks very sharp – as you’d expect from any Crank Brothers product. Installing a saddle on the Kronolog iss a relatively straightforward process, as long as you make sure that the bridge piece that sits between the saddle rails is precisely positioned. Mis-align it and you’ll be going in search of a hard-to-find small part to replace the plastic bridge you just cracked. Fortunately, it’s the same size as the aluminum bridges on other Crank Brothers seatposts.

The head design allows you to rotate the post so that the cable is coming in front or back, depending on your frame design and available housing guides. Just make sure you install your saddle carefully.

Clamping the remote lever onto the bar is a piece of cake, thanks to a long Torx screw, and it plays nicely with both Avid and Formula brake levers; it should work well with Shimano levers, but I’ll have to check that during the test. The long-ish lever can be attached on the right or left side of your bars, either above or below the bar. I always run my dropper post levers on the left, above the bar, for maximum functionality.

Lever on the left. It’s between the lock-on grip and shifter clamp in this photo, but ended up on the inside of the black brake lever clamp. The bar is a little cluttered, but I can live with it. Bonus points for designing the lever to look like a nifty little Crank Brothers logo.

The first thing that many people will notice about the Kronolog is that the lower portion of the post sits about 1” higher out of the frame than other dropper posts, because of the height-adjustment mechanism is longer than the collar on other posts. That shouldn’t be an issue for riders who run 7″ or more of post exposed from the frame (2” for the mechanism and 5” of adjustable post). Shorter riders or riders who run less post than that should check how much total post they have exposed before committing to the Kronolog.

The full-height post. Note how the height adjust mechanism sits above the top of the frame, which isn’t a problem for the taller kids in the crowd. Note also how the cable isn’t going to move when the saddle comes down. That’s a plus in my books.

I’ve got a few rides on the Kronolog so far, and have noticed a few things. First, you need to use more force at the lever to activate the locking mechanism and get the post to drop than with a hydraulic post. Once you do, however, it goes down quite smoothly and stays down. The fact that the post doesn’t slide up when you pick up your bike by the saddle is a good thing.

Returning the saddle to full height also required more force to the lever than a hydraulic post, but it was comparable to other mechanical posts I’ve used. There is a bit of a popping sound when the post releases to come back up, but unfortunately, there’s no noise that lets you know the post is at full extension, so you have to take it on faith that it’s at the top of its stroke. Thus far, there haven’t been any issues with the Kronolog staying up and I’m hoping that this design will prove to be more durable than other mechanical dropper posts I’ve used in the past. I have the pressure cranked up to 100 psi so it’s fast, and while it’s not lightning fast it’s adequate.

The very thin Kronolog lever, from the front of the bike. If you don’t find the sweet spot, you’re going to be pushing hard on the thin edge of the wedge. The knurled adjuster allows you to take up cable slack as it stretches after the inital installation. 

The fact that the cable attaches to lower portion of the post rather than near the head means that it doesn’t move as the post travels up and down. I’m pretty happy not having to suddenly contend with several extra inches of hose flopping around when I drop the post.

I’ve also noticed that lever positioning is important. If the lever is too far in towards the stem, you’ll be pushing on the thin and not entirely ergo outer edge. I’ve fine-tuned positioning and have found that with the combination of long fingers and a long lever, the best place is inside of the brake lever clamp. I also rotated the Kronolog lever around the bar for the first two rides, and have found what seems to be the sweet spot for me.

There’s been a very minor learning curve as I switch over from the dropper post I’m accustomed to, and I’ve found myself starting to push the lever when I want to up-shift or vice versa, but that should stop with a few more rides.

The air valve on the bottom end of the post is used to adjust rebound speed. I’m running it at the max pressure of 100 psi for the fastest return. The sides of the shaft are flat to prevent the post from rotating.

Performance on the Kronolog has been good so far, but most dropper posts work well out of the box. We’ll have to see how it holds up to a few months of use, abuse, wetness and grit on the Shore before passing judgement. I’ve had my share of issues with mechanical posts, so I’m wary but optimistic about the Kronolog. Stay tuned for the full review after the aforementioned torture testing.

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The NSMB.com First Date is a brief overview of a product’s specifications, as well as our initial impressions both on paper and in-field. It also covers how the marketers and engineers have pitched the product and how they intend to see it used – plus how we intend to test it, where it is being tested, and how long we expect to be testing it for. This is not a full review of the product yet but provides the background for a forthcoming review and allows reader feedback – perhaps there is something specific that readers want to find out about this product and the further review stages can address that.

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Do you share Stuart’s wary yet optimistic view of Crank Brothers’ new dropper post? Would any armchair engineers wish to on the mechanism? Drop your comments below…