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Over the past winters I noticed that my dropper post (rockshox reverb) stops working around 0°C (32°F). I usually manage to lower it one last time but then it doesn't rise anymore upon pushing the button (I ensured several times I'm pushing all the way down and tried keeping it pushed for a minute). Once after the ride back inside, it starts working again.

  • Is that a known feature?
  • Any suggestions for mitigation?
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    Could it be water freezing somewhere inside the mechanism? Does it work when you “help“ it along and pull the saddle?
    – Michael
    Commented Jan 1, 2021 at 17:46
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    @Michael when pulling i get the same behaviour as in the warm when i pull without pushing the button: i can move the seat up a bit but it jumps back down when i let go. (afaik one shouldn't do that with the reverb, but i tried anyway in case it needs a bit help overcoming friciton or gravity)
    – pseyfert
    Commented Jan 1, 2021 at 18:36
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    Dribble a little whiskey from your flask down around the post.
    – Daniel R Hicks
    Commented Jan 1, 2021 at 18:40
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    Whiskey can get sticky when it dries Vodka may be better.
    – mikes
    Commented Jan 1, 2021 at 19:54
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    My Reverb has worked fine so far at cold temperatures. It's my cable-operated BrandX dropper that doesn't work below 0°C – it fails to lock then, which is super annoying because you can neither ride properly seated nor standing anymore.
    – leftaroundabout
    Commented Jan 2, 2021 at 15:43

3 Answers 3

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The reverb, much like Shimano brakes, has a known issue when operating in the cold. The oil inside simply thickens too much to properly flow through the lever and hose. The oil flow through the damper also gets constricted. I don't think there's really a solution because switching to a thinner oil might cause issues in the summertime, such as the post rebounding too quickly and damaging internal components. Of course, you could switch to a different dropper with a more modern design that does not suffer from that issue.

Do NOT pull up on the reverb when it is compressed, even if the lever is being pushed. You will suck air past the seals and cause the infamous "Reverb squish" (where the post is no longer capable of staying rigid thanks to air being mixed in with the oil, and you basically have a very expensive suspension seatpost. Cannot be fixed with Viagra.)

Edit: If your particular model has it, try turning the speed adjuster to full open/fastest. That might help.

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  • That said, if it has the wrong oil in it, a bleed with the right oil might help.
    – mattnz
    Commented Jan 1, 2021 at 21:36
  • @mattnz That's true. Reverbs in general aren't the greatest though, and the cost of getting it bled might be better spent buying a different dropper. Even the budget $130 droppers nowadays work better.
    – MaplePanda
    Commented Jan 1, 2021 at 21:42
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I am speaking only from a third person point of view as I primarily ride on the road, but could it be the gas/fluid actuating your dropper is affected by the cold as that seems the most logical.

These two links perhaps may help and maybe your LBS or Rockshox warranty department can shed some light on if there is a known issue with your particular model.

A full hydraulic dropper post uses a sealed hydraulic remote to control the seatpost. The system itself works much in the same way as a hydraulic brake cable, whereby a piston (the lever) pushes fluid through a hose which actuates the dropper at the other end.

from https://www.bikeexchange.com/blog/buyers-guide-to-mountain-bike-dropper-seatposts

  • It happens in the cold, whether bike is ridden or parked or on a rack, so its not just riding in the cold.
  • Release all the air pressure then bleeding the hydraulics may help,
  • Increasing/decreasing the air pressure may help, with a shock pump, figures of 250~260 PSI were quoted.
  • Sideways play in the top or sag when fully extended may mean a rebuild with new seals, or a complete replacement.

From https://www.mtbr.com/threads/rockshox-reverb-cold-weather-issues.993072/ summarised.

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  • Excellent links, but if the remote web site vanishes, then there's nothing left in this answer. You can write up the main points from the links in case they reorganise (it happens). I've had a go at that, but droppers aren't my thing either so please update or revert as you see fit.
    – Criggie ♦
    Commented Jan 1, 2021 at 22:56
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    @Criggie - I am good with the edits. I also think MaplePanda and mattnz was able to add more relevant info from first hand experience which adds to this answer thread.
    – Tude Productions
    Commented Jan 2, 2021 at 12:26
  • Sideways play isn’t an issue, nor is it a symptom of a greater problem. It just stems from the tolerances of the keys and keyways.
    – MaplePanda
    Commented Jan 2, 2021 at 18:47
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I had water on my actuator from washing, that froze when it got to -5 or so. I cleaned it up and sprayed wd40 on and it did help a bit, maybe some de-icer on it will help

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  • But is this something that would happen regularly, every time the temperature drops?
    – DavidW
    Commented Nov 14 at 12:15

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