Review: Crank Brothers Kronolog Dropper Post – Weighed, Dismantled & Ridden
Crank Brothers’ Kronolog dropper seatpost arrived a few days in advance of the official introduction back in March, so we’ve had a couple months of riding on it. We’ve also dismantled it, weighed it and given it a good once over.
The basics: It’s a mechanically controlled air spring post that’s infinitely adjustable. A big deal is made of preset positions by Fox and Specialized with their posts, but if you like being able to set it where you want it, the Kronolog obliges with a simple push of the lever. Rather than slotted channels to prevent rotational play, Crank Brothers flattened the sides of the telescoping section and shaped the internal seals and guides accordingly. The result is a (thus far) smooth operating post with as close to zero play as we imagine possible. Other nice features are a secondary air chamber that damps the return speed, slowing it down as it nears top out and keeping your special bits safe. When you pull up on the saddle, it won’t raise the seat because the jam plates lock the post into position in both directions. Lastly, the lever is very easily mounted under or over the bar and on either side.
Fit and finish on the post and remote are top notch, as with most Crank Brothers products we’ve seen. And while the Kronolog solves some of its predecessor’s problems and addresses common complaints with dropper posts in general, there are a few concerns worth mentioning. Drop in for the full review…
UNBOXED & WEIGHED
A simple Schrader valve on the bottom is filled with a shock pump. Max pressure is 100psi, but I found 70psi to 80psi to be adequate. Lighter riders may want less, but it’s easy enough to experiment. The key is to get the pressure light enough that you can use your weight to only drop it as far as you want. To0 firm and it’s hard to “fine tune” the position. Too light and it’ll just drop too fast.
The saddle clamp is 3D forged as part of the telescoping post, not bonded on. This makes it stronger and lighter. It clasps the outside of the saddle rails and squeezes them toward the center piece, which prevents the rails from bending inward. Angle and everything is adjusted via a single T25 Torx bolt on the left side. After a bit of time on the trail, we had to really loosen it up to make small angle adjustments, but it never slipped. It is set at a slight angle already, so you’ll need to make sure it’s put into the bike the right way when first installing it, otherwise you’ll never get your saddle flat.
The lever is simple, lean and beautiful. Both of these parts are offered in colors to match other CB components.
Slide the cover off and you’ll see the cable actuated jam plates. When “closed”, they’re literally jammed into the post at opposing angles on both front and rear, giving them four contact points to hold it in place. Because they’re opposed, they prevent upward and downward movement until you press the lever.
We got the larger 31.6 post. It weighted in at 566g. The cable comes preinstalled and is 40″ (101.5cm). All of our testing so far has been on a size Large Devinci Atlas 29er, and this was exactly the perfect cable length with the entry point on the post facing forward. If the top tube were any longer, we’d probably have had to put a longer cable and housing on it.
On that bike, there was plenty of static post. Even at 6’2″, I had a bit more than two inches of post left before it would have hit the minimum insertion.
Our testing so far has been on a lot of XC-ish trail, which puts the rider’s weight on the post a lot more than constant gravity riding. We’ve taken it to the mountains, too, and used it as intended. On those rides, the action was smooth and quick, and return to start was predictable. The slow down in return speed at the top is greatly appreciated.
On the flatter rides, we were swapping the bike back and forth between riders. Rather than pull out the mini tool each time to adjust saddle height, we simply pushed the lever and played with the post until it felt right. Lazy, yes. But a good test: In reality, dropper posts are generally used fully up or fully down. There aren’t too many instances where you’re going to spend much time in a middle setting. We did spend a lot of time in various positions, though, and the post held solid the entire time.
Based on horror stories we’ve heard of other posts developing play or failing after a few rides, two months on this one without issue tells us it’s off to a good start. We’ve had zero problems with the post and it’s developed no play. That said, there are a few issues we’re watching closely, all of which we discovered as we dismantled the post to flip the cable entry to the rear (and feed our insatiable desire to tinker and see how things work!).
DISMANTLING & SWITCHING CABLE ENTRY TO THE REAR
Our testing so far has been with the stock set up, and that’s with the cable entry on the front. In order to flip it around to the rear, you need to disassemble it. This requires a Park Tools SPA-2 spanner tool to unscrew the bottom cap. First, remove the Schrader valve cap, then have at it. Ours was pretty tough to open, so I’d recommend leaving the saddle on and using it as leverage (that’s why I’m standing on it). If you love your saddle, put it on a towel first.
Once that one’s off, squeeze the lever and slide the post all the way down to get to the second piece you need to use the spanner on (left). This one was much easier to remove. The full internals are on the right (click to enlarge). Once that’s pulled out, press the lever again and pull the telescoping post out, spin it 180º and reinsert. This effectively puts the cable entry point on the back of the post. Honestly, we wish the post’s saddle clamp weren’t directional; this would make it much easier to run the Kronolog in either direction right out of the box.
The piston has a good bit of grease to keep it sliding freely. On the bottom of the piston is a spacer (about 10mm) that can be moved above the piston to shorten travel by that amount. Add up to 20mm in spacers. Stock travel is 125mm. Shorter riders on smaller frames may need to limit the travel to be able to fit themselves on this post, which is why they made it internally adjustable.
As I was poking around the seals, I noticed a couple of metal shavings (two of them form an “X” just above a seal in the photo on left). At first, I thought perhaps they were manufacturing remnants. That wouldn’t have been good, but at least it wouldn’t have meant anything was wrong with the post.
Unfortunately, the source appears to be the telescoping post. It looks as though the metal jam plates dig into the post slightly and are scraping metal off. On the left you can see markings from all the various positions we’ve set the post in. Most of these marks are just normal metal-on-metal superficial scratches and aren’t worrisome. A few, though, are larger and are visibly scratched into the post.
I’m holding off on forming a final opinion yet. Yes, at first glance this looks bad. Real bad. But it could be that just a few bits came off and now things are fine. Time will tell, and I plan on putting a lot of time on this post over the summer. Worst case is that the post and/or jam plates will scratch, scrape and wear off enough material that they’re no longer able to hold the post in place.
The other issue, which is both minor and quite possibly entirely my fault, is that the cable housing cracked right at the entry point. It seems kinda weak that it would crack almost to the point of separation so early in its life, and we haven’t wrecked while aboard the post, but who knows. It’s a minor thing…the post still works as is and changing out the housing isn’t that big of a deal. I may need to do it anyway to extend the length…and I think Gore Ride-On makes an upgrade kit for just such things. Mmmmm….Gore Ride-On.
NOT SO DEEP THOUGHTS
Overall I like the post. I want to keep liking the post. There’s a lot to like. I want Crank Brothers to have a winner on their hands. But at the moment, I’d say hold off on purchasing. I’ll talk to Crank Brothers and see what they say, and we’ll keep riding it and report back.