Crankbrother's Kronolog telescoping seat post steps away from the hydraulic internals that were used within the infamous Joplin design, instead utilizing a full mechanical layout that greatly resembles the locking plate system found on bar clamps. The design makes the Kronolog the only mechanical post that is infinitely adjustable, allowing users to select any seat height between its fully dropped and fully raised positions. Total available travel is 125mm, although that number can be lowered by way of an internal spacer. The 465 gram Kronolog retails for $300 USD, and is available in 30.9 and 31.6mm sizes.
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The 125mm travel Kronolog employs proven technology that is very similar to what you'll find on the common bar clamp.
Crankbrothers Kronolog details:
- Adjustment range: 125mm/5in (can be lowered 20mm via an internal spacer)
- Infinite height adjustment
- Operated by a bar mounted remote w/ a standard shift cable (4mm brake housing recommended)
- Diameters: 30.9mm, 31.6mm
- Post length: 405mm
- Weight: 465g/28g (30.9mm post/remote)
- Warranty: 2 years w/ proper maintenance
- MSRP: $300 USD |
A set of twin steel plates, each one encircling the post's upper tube, sit within the larger diameter portion of the post's lower tube. A spring positioned between the plates pushes them apart, forcing both the forward and rearward inner edges of plates into contact with the upper tube, which in turn holds it steady from rising or lowering. When the remote lever is pushed the cable pulls the plates together so that they are parallel with each other, allowing the upper tube to cycle freely. Release the remote lever and the spring between the plates force them apart at an angle into the upper tube's clamping surface. The system may sound complicated at first, but it is actually one of the simplest telescoping post designs out there, with possibly only the Gravity Dropper being more straightforward. Crankbrothers is quick to point out that the inspiration for the post's locking mechanism comes from the locking plate design found on bar clamps, a system that has been in use for countless years.
An air spring is employed to raise the saddle, with it being adjustable via a schrader valve at the bottom of the post. Air pressure is recommended to be set between 55 and 75psi, which will also effect the effort it takes to lower the post. Adding air will speed up the Kronolog's return speed, while lowering the pressure will slow it down.
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| The housing stop is located in an insert at the lower plate, while the upper plate is home to the cable clamp insert. Pushing the remote pulls the plates parallel to each other, which lets the upper tube slide freely until cable tension is released and the plates return to an angled position, gripping the upper tube. |
The Kronolog's clamping mechanism is tucked away inside the larger diameter section of the lower tube that, when the post is installed into your bike, sits just above the frame's seat post clamp. This brings us to what is likely the Kronolog's most attractive feature: the design means that the actuation cable is stationary - it does not move as the post goes through its travel - so that there will not be a surplus of cable loop that can rub on your leg or rear tire when the seat is in its lowered position. Riders who have had to use copious amounts of zip-ties to keep their dropper post cable in line will likely appreciate this, although the design also limits the Kronolog's insertion depth. The Kronolog measures 217mm/8.5'' from maximum insertion to the saddle rail clamp when at full height, compared to a Reverb's 195mm/7.6'' height. Riders with short legs take note, the Kronolog may not work for you.
The post is operated remotely (
there is no post mounted lever option) via a hinged, bar mounted lever that can be fitted to the top or bottom of either side of the handlebar. The sturdy looking remote is home to the shift cable that operates the post, with a small spring fitted under the cable head in order to take up the 3 - 4mm of cable slack that the Kronolog requires to function properly. A barrel adjuster makes tuning cable tension easy, and the post comes from Crankbrothers pre-strung with 4mm brake housing that offers more flexibility than shift housing.
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| The actuation mechanism and cable anchor point are both found under a removable cover on the post's lower tube. The cover is slid up to gain access to the internals, and slid back down over top and clicked into place. The cable is pinched in place within an insert in the upper plate by way of a 2mm set screw. |
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| The upper tube and clamp head are both forged from the same piece of aluminum, eliminating the bonded joint between the two that is found on most other designs, and a juncture that can often be home to creaks and groans. |
The Kronolog comes ready go out of the box with a cable and housing already installed, but we stripped it down in order to see how easy it was to setup the post up from scratch. Fitting a cable is relatively simple, and Crankbothers' illustrated instructions do a good job of explaining how to go about it. There is a small and very important spring, positioned under the cable's head that can be easily lost if you are not paying attention, that allows for 3 - 4mm of lever free play before cable tension is applied to the post's locking mechanism. This part of the setup is crucial for consistent action from the Kronolog - too much cable tension and the post will lower or raise on its own, so it is important to get it correct. A barrel adjuster on the remote lever makes this task easy, and the lever is also hinged for straightforward installation and removal. We installed ours on top of the bar at the left side, but it can be positioned on the top or bottom of either side.
The saddle clamp is a single bolt affair, although it appears to be offer quite a bit more support than what was employed on the older Joplin post. The torx head bolt is to be clamped at 106 in/lbs, and the female side to the clamping bolt is captured within the post's head to make fitting a saddle as easy as possible.
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| The dust seal conforms to the upper tube's oval shape (left) to keep grime out of the inner workings. Knurling has been added to the clamping surface of the upper tube (middle). An air valve that is located at the bottom of the post lets users adjust the pressure in order to tune rebound speed. |
The Kronolog has close to zero play at the nose of the saddle, much less than what we've seen from other designs. This lack of movement is down to a few reasons: it's forged upper tube employs flat sides that mate with a bushing chosen specifically for each post, and the twin locking plates also grip firmly to help take out any wiggle. Having said that, we'll admit the even the worst offending posts in this regard don't have us noticing their excessive play when on the bike, but it is nice that the Kronolog is the tightest feeling of the many posts we've tested. The remote lever is also among the most ergonomic that we've used, with the thumb paddle in just the right spot in relation to its bar clamp. Its thin, hinged mounting band takes up very little real estate, letting you position it where it makes the most sense for you.
The Kronolog's most talked about feature has to be its stationary cable entry point located on its lower tube, meaning that the cable stays put as the post goes through its travel. This is in contrast to the majority of the competition who's actuation cable terminates at the post's head. The latter design often necessitates creative cable management with far too many zip-ties, and even then it is common to either have surplus cable hang out from the bike that rubs on your leg or rear tire when the saddle is lowered. No such complications with the Kronolog: size the cable to the correct length and forget about it. Some riders may not be fans of the bulbous 'growth' on the lower tube that houses the cable entry point and locking mechanism, but form follows function with the Kronolog.
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| The locking plate mechanism allows the saddle height to be positioned anywhere between full height and fully dropped. |
The post's action is reasonably smooth in a mechanical sort of way, even after many rides in nasty conditions and an equal amount of abusive cleanings with a power washer. Hit the lever and the saddle rises or lowers fluidly, although it does take slightly more force to lower than some of the competition. The ability to infinitely adjust the saddle height is beneficial on steep and technical climbs where a slightly lower center of gravity can lift your confidence. The same can be said on rolling or technical portions of flat trail, both scenarios where a slightly lower seat height can make a world of difference. Having also used telescoping posts that offer a set 'cruiser' position that is slightly lower than full height, we have to say that we do prefer the Kronolog's infinite adjustability that allows you to decide the height that works best for you. The twin locking plate design will also not allow the saddle to be pulled up when already lowered unless the remote is pushed, a plus if you ever have to lift your bike by its seat when out on the trail.
Required lever force isn't excessive, but you are fighting the spring between both locking plates, forcing them together to free the upper tube, and you can feel this in your thumb. Pushing the remote lever while weighting the saddle results in it dropping freely, unlike some of the mechanical designs out there that require you to unweight the saddle slightly to keep the mechanism from jamming. This, along with the very ergonomic remote, go a long way in making the post highly intuitive when in the heat of the moment on the trail.
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| The remote is one area where many manufacturers seem to fall short in. Not so with the Kronolog. Its ergonomics are spot on. We also didn't manage to damage it, despite multiple bike-cartwheeling spills, and plenty of flat repairs that saw the bike upside down and resting on the remote. |
There is a lot to like about the Kronolog post, but we still wouldn't call it trouble free. The design uses air pressure to raise the saddle, a system that is clearly going to be much lighter than a coil spring, but it isn't without issue. The post's return speed slows noticeably as it nears the top of its travel, a trait that Crankbrothers' boasts ''
... allows the saddle to return to a normal riding position in two, smooth stages'' but, more often than not, it just left us wondering if it was actually at full extension. An audible noise, a simple '
klunk' when it tops out, would be welcomed to let the rider know that yes, the post is at its full height. The air spring had the same effect at the opposite end of the stroke, sometimes making it difficult to get it to fully lower in the heat of the moment, and even requiring a firm push with the bum to get that last bit of travel out of it. While accessing the final 10mm of the Kronolog's stroke might not seem like a big deal, its 125mm of travel should be easily available. The post's single bolt saddle clamp also rotated once under us, putting the saddle at a wonky angle and further enforcing our belief that all saddle clamps should use two opposing bolts.
The bigger issue, though, involved the Kronolog's inability to hold the saddle at either full extension or fully lowered. The post's upper tube makes use of a knurled surface where the locking plates grip hold, and it took about a month's worth of riding time until this knurled aluminum clamping surface was worn smooth by the twin steel locking plates in the two locations where it was most commonly locked into position: fully extended and fully dropped. The profile of the upper tube was altered enough that the locking plates simply refuse to hold the post at full height when the saddle is weighted (letting it drop roughly half of one inch ), and it also will raise up slightly until the plates grip onto an undamaged section of upper tube when fully lowered. This slipping will even occur when the actuation cable is not attached to the locking mechanism, and it means that we actually have to raise the post slightly in the frame to compensate for when it lowers under our body weight. This compounds the issue of it popping up a half an inch when it should be in its fully lowered position on a downhill section of trail. The damage can be seen in the photo to the right.
Crankbrothers Responds: We talked to Crankbrothers' Clark Brewster, the lead developer on the Kronolog project, regarding our concerns about their new telescoping post. Brewster was quick to point out that the Kronolog employs an O-ring atop the post's piston that acts as a top out bumper, and that removing it will result in the audible '
kunk' that would let us know that the saddle is at full height. The modification is quite simple, and the same job can be performed on the damper piston to allow the rebound speed to be increased as well. The bigger issue at hand, though, is the scoring we experienced on the post's upper tube. The grooves that have been machined into the post from the factory are, Brewster says, "
purely cosmetic and they are there to hide the marks that naturally occur with use. Over time, the marks form a nice patina, but we found that without the cosmetic grooves, the marks don't look very good." Brewster continues, "
The grooves however, are a good indicator of wear. If there are no grooves, it means that the diameter of the circular section has changed, and some sort of bad wear is occurring." This brings us to the premature wear inflicted to our Kronolog that, Brewster says, is down to an incorrect setup.
The Kronolog's relatively simple twin steel locking plates either must be fully open to allow the post's upper tube to cycle up and and down freely, or fully closed against the upper tube in order to hold it in place. It's when the rings are only partially activated that damage to the upper tube will occur, says Brewster. "
Please note that during our ride testing, we have posts that have over 2000 hours of riding on them," he continues "
and without the shaving or slipping that you experienced. Fundamentally, the system works and is robust. When the system is adjusted correctly (with the proper amount of lever play), and the parts are made correctly, then the post should operate extremely well." Brewster puts the blame for our post's damage on either faulty cable tension setup or a burr on the cable that prevented it from releasing properly, and also admits that 3 - 4mm of lever free play is ideal instead of their original number of 2 - 3mm.
Pinkbike's take: | There is a lot to like about Crankbrothers' Kronolog seat post; its stationary cable entry point, infinite adjustability, great remote, and sturdy saddle clamp all adding to its point tally in our minds. But it does, unfortunately, have a few foibles. More consistent compression and rebound speeds throughout its entire stroke, as well as an audible indicator as to when it is at full height, would make a huge difference in the performance of the post out of the box. But it's the damage to the upper tube that concerns us the most. The twin locking plate design has been proven in other forms for many years, but we have our reservations about its use on the Kronolog if its function is compromised by the cable being out of adjustment by only a millimeter or two, although we still stick to our guns about our installation being spot on. Ideally, we'd like to see Crankbrothers change the clamping surfaces on the upper tube to something sturdier before we give the Kronolog full marks, eliminating the chance of damaging the post.- Mike Levy |
When it will be time to overhaul the thing, I will try to put something in to limit the extension - I don't need 125mm of travel anyways. 70-80 will be enough and I will get less leverage on bushings
