CrankBrothers have announced a new height-adjustable seatpost called Kronolog, which replaces their Joplin line of mechanical dropper posts. The Kronolog is a 5in/125mm mechanical adjustable post that costs US$300/£249.99.
Over the five years that CrankBrothers have been producing the Joplin, they've worked hard to make the system more reliable. They've also increased travel from the original 3in to 4in, then 5in. However, that former attribute – reliability – remained the Achilles heel of the Joplin hydraulic design.
“Through our experience in the adjustable seatpost category, we've learned that the main source of failure is an overcomplicated design,” said CrankBrothers via press release. “Hydraulic posts are heavy and problematic, so we took a different route. We wanted to create something simple, and it became clear that a mechanical design was optimal for an adjustable seatpost.
"The Kronolog was developed over a two-year process that included extensive design, development, prototyping, testing, redesigning, retesting, etc. The post went through 10 design iterations, and even more when you include incremental changes. Through the process, the post was extensively tested both in the lab and on the trail.”
There have been two schools of dropper post design, historically: mechanical designs with pre-determined height adjustment points and hydraulic, à la CrankBrothers' Joplin, with infinite adjustability. The former mechanical design can generally be considered more durable, and the latter hydraulic type generally offers better on-trail performance, because you’re not required to hit exact locking points and the action is more controlled.
CrankBrothers say the Kronolog is more robust and reliable because of its new mechanical design, but use of an air spring and adjustable air damped return means it feels much like a hydraulic system. The damped return stroke happens in two stages. The first is snappy, and the second slows the post in the final 1in of return travel, so as not to catch the rider off guard. CrankBrothers say that because there are fewer parts in the new system, there are fewer failures, citing that Kronolog passed EN fatigue testing by nearly triple the requirement. They'll offer a two-year warranty with the new dropper.
Hans Rey introduces the new CrankBrothers Kronolog
Unlike other mechanical systems, the Kronolog is infinitely adjustable through a unique keyed quill system, which is also said to eliminate nearly all rotational movement – another pitfall of many designs. Once locked into position, the post resists both downward and upward force so as to remain fixed when picking the bike up from the saddle; hydraulic designs have a tendency to move.
“I've been testing the Kronolog and working with the product managers and engineers for the past year,” said Richie Schley, one of CrankBrothers' marquee athletes. “It's a mechanical system, so it's light, strong and reliable. Don't let the "mechanical" throw you off though. It is a CrankBrothers product, so it has a sleek look with attention to design, right down to the cool CrankBrothers logo remote.”
Other unique advantages of the Kronolog are its low fixed remote cable position, internal travel reduction in 20mm (0.78in) increments (via spacers), and a 50g weight reduction when compared to the Joplin 5 remote post.
The kronolog will be offered in red and black, standard, with aftermarket color kits available
The Kronolog post weighs 465g and the remote adds another 28g, plus the weight of cable and housing. CrankBrothers will offer black-and-red and black-on-black color schemes, standard, plus aftermarket color kits, which cost US$45 and replace the seat clamp and lever, in black, blue, gold, orange and red. The post will be offered in 30.9mm and 31.6mm diameters, and will be available within two weeks in the US, but will not be available in the UK until June, according to distributors.