Tech Tuesday - Crankbrothers Kronolog Cable Replacement
Crankbrothers recently released their brand new Kronolog telescoping post, a much anticipated replacement for their original Joplin. The Kronolog features a full 125mm/5'' of adjustment range, all without any set stops in its travel, and depends on an air spring to return it to full height. The post's internals are entirely mechanical, meaning that it doesn't depend upon any oil seals to function properly, and it uses a shift cable to control its movement. Unless you live in the driest of climates, you likely know full well that a season of rain and mud can contaminate a cable, keeping it from moving freely within the housing and requiring you to replace it. Below, we show you how to perform this task on the Kronolog.
The Kronolog depends on two spring loaded plates that encircle the post's stanchion. Pushing the remote pulls the actuation cable and unlocks the plates, allowing the post to cycle up or down. Release the remote and the spring forces the plates sit at off angle against the stanchion's clamping surface, firmly holding it in place. All of this is hidden under a protective cap that can be slid off to access its inner workings. An air spring (set between 50 and 80 PSI) returns the Kronolog to full height. The result is the only infinitely adjustable mechanical post on the market.
What's needed: • 2mm hex key • Cable cutter • Replacement shift cable | Some helpful pointers • The 2mm set screw that holds the cable in place requires no more than 1 Nm of torque to do its job. That's just 0.73 ftl/b. No need to overdo it. • If you need to replace the housing as well, be sure to not cut it too short. Doing so can lead to routing issues, or cause the Kronolog to inadvertently activate. It is recommended to use brake housing because it's more flexible than lined shift housing, allowing it to be routed smoother. • There is a small spring under the head of the shift cable that allows for a slight amount of lever movement before activating the post, just 2 - 3mm. Don't lose track of it when you pull the old cable out. |
Step 1 - Start by sliding the protective cup up and off of the post in order to expose the locking plates and cable anchor.
Step 2 - The cable is clamped in place in the upper barrel (the lower barrel serves as the housing stop) via a small set screw. Carefully use a 2mm hex key to loosen and completely remove the set screw, setting it aside in a safe spot.
Step 3 - You'll now need to pull the old cable free from the actuation mechanism. You may be able to simply slide it out from the housing, but our cable was crushed by the set screw enough that it didn't want to slide through the barrel. Pushing the two locking plates together gave us enough slack to grab the upper barrel and tug it free, letting us snip off the damaged section of cable and easily pull it out of the housing. Another way would be to cut the cable between the plates and use pliers to pull the remaining from the top barrel.
Step 4 - Take note of the small spring sitting under the cable head - it can be easily lost if you quickly pull the old cable out of the remote without knowing about it. Push the cable out slowly and it should come with it.
Slide the spring onto the new cable until it is under the cable's head, and then feed the cable through the remote and the housing.
Slide the spring onto the new cable until it is under the cable's head, and then feed the cable through the remote and the housing.
Step 5 - Slide the upper barrel down over the cable, with its lip in the up position so that it nests into the upper locking plate.
Step 6 - The Kronolog requires minimal cable tension when compared to a shifter or cable brake, which is why we recommend dialling the remote's barrel adjuster out two or three turns before clamping the cable. This will allow you to remove cable tension by turning the barrel adjuster back in if you pulled the cable too snug during installation.
Pull the cable taut enough to take the slack out of it, but not as tight as you would a derailleur cable, while you snug down the set screw to just 1 Nn with your 2mm hex key. The set screw only requires a very low torque to hold the cable in place, over-tightening it will only damage the screw and make your life hard the next time you need to replace the cable.
Pull the cable taut enough to take the slack out of it, but not as tight as you would a derailleur cable, while you snug down the set screw to just 1 Nn with your 2mm hex key. The set screw only requires a very low torque to hold the cable in place, over-tightening it will only damage the screw and make your life hard the next time you need to replace the cable.
Step 7 - The remote requires 3 - 4mm of free play before applying tension to the cable, which is taken up by the small spring under the cable's head. No free play means that the cable is too tight, possibly allowing the post to lower or raise on its own. If your cable has too much tension, simply turn the barrel adjuster in (clockwise) until you have the required amount of tension.
Use your cable cutter to snip the new cable as close to flush with the top of the upper barrel as possible to keep it from making contact with the ceiling of the protective cap. Do not install a cable crimp for the same reason.
Use your cable cutter to snip the new cable as close to flush with the top of the upper barrel as possible to keep it from making contact with the ceiling of the protective cap. Do not install a cable crimp for the same reason.
Step 8 - Turn your handlebar in both directions while putting weight on the saddle in order to be sure that the housing isn't too short, there should be no movement in the lower plate. If there is movement, then you do not have enough play in the lever. Slide the cover back down over the actuation mechanism - you should hear it click into place when it's home - and cycle the post up and down a number of times to check your work.
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I just still am not seeing any amazing steps forward since the Reverb?
went from using an infinitly adjustable post to using the stepped speedball post that came on my spesh evo and much prefer it as i know exactly how far it will go up or down whenever i press the button rather than an infinite post which most of the time ended either too low or too high
"The result is the only infinitely adjustable mechanical post on the market."?????
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