Ever get that not-so-smooth, sticky feeling from your dropper seatpost? Where it doesn’t drop easily or won’t return to full extension?

At Sea Otter, Rockshox installed their latest Reverb on my bike, then we hit the road home with a planned stop in Sedona. Once there, I adjusted my seatpost height and hit the trail. One of the other guys riding with us was on a borrowed bike, so he, too, adjusted seat height and off we went. As usual, we made a few early stops to fine tune our position on the bike, using our multi-tool trailside to adjust things. Then we hit the first descents and noticed that our dropper posts weren’t coming back up. Or they felt a little “thick” going down. Or both. What was up?

how to fix a sticky dropper seatpost

We ask a lot from our Dropper seatposts. Like a fork, they have constant lateral forces placed on them, creating a shearing effect every time you drop it. They also need to resist twisting, and they need to support your weight. It’s no wonder they’ve taken years to become reliable. And now we’re asking them to telescope a massive 170mm or more in some cases. And we want them lightweight, right? Without any creaking? And they definitely need to stop at any point in their travel and hold position indefinitely. Put it all together and it’s a tall order.

Inside the posts, there’s usually some combination of gas (usually air) pressure and hydraulic systems to push and lock them. Some use mechanical stops, but there’s still a system of levers or valves required to operate them. A lot can go wrong. But time and again, we’ve found it’s usually something far simpler that has us cursing:

User error.

Over tightening the seatpost collar is very often the culprit. Because we ride so many different bikes, we’re often fiddling with seat height on the trail, cranking it back down and getting on with the ride. And often, this causes problems. On our Sedona ride, both of us experienced poor performance. Running through all of the myriad things that could be tried -bleeding the hydraulic Reverb lever, removing the post to adjust cable tension, checking air pressure on models that allow it, etc.- it finally dawned on us that maybe, just maybe, we’d overtightened the collar. Boom. Problem solved on both bikes.

Why this works: A dropper post is basically a cylinder sliding inside another cylinder. If you clamp the outer cylinder too tight, it squeezes the inner cylinder and prevents it from sliding freely.

IT’S USUALLY AN EASY FIX

Bottom line, if you’re dropper isn’t sliding down easily or returning to full height without manual assistance, slightly loosen the seatpost collar and try again. You only need it just tight enough to prevent the post from slipping down. Maybe you recently adjusted your seat height to accommodate a new shoe/pedal combo. Or your buddy borrowed your bike. Things happen, and rarely do we use a torque wrench for every adjustment. But this has solved more dropper post woes than we can remember, so give a try.

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25 COMMENTS

  1. If you live at decent altitude and go to sea level, an air assist dropper will need air or it will be “sluggish”.
    Sea level to altitude…it’ll be very fast.

    Check you suspension too.

    • That’s a nice anecdote and all, but it’s nothing near evidence of quality. As someone who services both, I’d say they both “fail” just as often. Usually it’s caused by lack of service, and sometimes a faulty post.

      At least with a reverb I can bring it back to factory fresh performance without replacing the entire damper. Same with Fox, but that’s not a fair comparison.

  2. This is a good lesson about problem solving: When the cause is not apparent, it’s usually best to start with the least invasive solution.

  3. Specialized, Ritchey, Bontrager, and I’m sure several others make preset torque wrenches (typically 5nm, often others are available) in the ballpark of $20 or $30 and they are some of the best money you’ll ever spend.

  4. Another issue that people are oft overlooking is seat angle and body position when trying to drop the post. Putting your weight too far back on the saddle can cause the post to bind.

  5. I’ve three bikes, two with the Command Post IR and the other with the IRcc. Six months and I have yet to touch them, and they both work flawlessly.

    Side note: I have NEVER had an issue with PF BBs. Why? Because I RTFM before I install it.

    • it’s not because you read the manual it’s because manufacturers quietly figured out how to make them not suck over the last 10 years

  6. Br oveetightening seatposts by that much doesnt give me much confidence in their reviews
    You gotta go very hard to achieve that on a reverb. If youd service one youd notice why:

    The tube design is overbuilt so that you can clamp it hard enough to ti unscrew the bolts. Additionally pressure is spread around the tube and not in a single location. It is very very hard to bend a tube that way.

    So… Yea. Ask sram/rockshox you’ll see.
    Disappointing.

  7. One of the most common reasons droppers stop working properly and start sagging is that people pick their bikes up by the saddle while the seat is down. By pulling up on the saddle, the post can extent and air can then work its way into the hydraulic cartridge.

    • Just reading why seat posts stop working and I think Keith has hit the nail on the head reference the problem I have. My seat will not come back up it’s as if I have create a vacuum in the seat post. How do I solve the problem, can anybody help ?

  8. Hah! Reverb! Good luck with THAT! My Thomson Elite Covert is 3 years old and the only service done to it is one replaced cable.

    • Uhhh… Maybe it’s time for service?! Waiting 3 years isn’t exactly something to be proud of. At least lube the dang wiper and bushing. The oil and seals do all the work!

    • All posts have issues, had 2 Thomson break with the first 5 miles of use. My Reverb is on the second year without any maintenance yet.

  9. Good comment in there about not lifting on seat. Air mixed with oil is bad juju. 5nm, 6nm Max. Everyone that turns bolts on a bike should have hand torque wrenches. I keep a Park ATD-1 on bench and in car. Lot of disagreement on whether this matters. Calling any tech service will recommend you to check torque on clamp.

  10. This is my first mtb with a dropper post. It had been working like a charm and I had been getting a lot of use out of it. I had only ridden my new trail mtb three times, when after I gave it a wash, I couldn’t get my dropper seat post to drop. Turned out the cable was not pulling. I loosened the hex nut at the lever and the pulled the cable with a needle nosed plier about a mm until it was tight and then retightened the hex nut and I was back in business. Working like a charm. Must have been new mtb stretched cable syndrome.

  11. washed my bike after very muddy/gritty ride then dropper wont work. loosened the seat post clamping nut and did it back up just enough so the post wont move (twist or drop) while im riding and it goes up and down great once then back to square 1. any ideas on what i should do?

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