LH Thomson dropper seatpost coming in 27-2 diameter and in road bike versions

LH Thomson introduced their dropper seatpost to great fanfare at Eurobike last year and have been hard at work making sure it meets expectations when it launches in April 2013.

I just visited their factory in Macon, GA, (separate post on that coming soon) and their PR man Dave Parrett spilled the beans on its progress and some upcoming variations.

While the recently introduced handlebars are coming from Taiwan, the dropper post is an even more international product. Parts are sourced from France, Malta, Taiwan and the US, among others. By the time it’s final assembly occurs in Taiwan, all external visible parts will be made in-house by Thomson, but internals are outsourced. Parrett says it’s essentially half of a suspension fork, and while they’ll eventually bring some more parts in house, probably not the suspension internals. That’s because their supplier had to ensure they last for two years minimum, and if Thomson started making some of the parts (valves, etc.) and something were to fail prematurely, the finger pointing would commence. Better to let the experts in their respective fields do their job.

Parrett says the cartridge is actually strong enough on its own to hold the rider, but for obvious reasons, it’s kept safely inside a sliding post. One such reason it to prevent rotation, and the original design we saw at Eurobike has changed a bit. They originally shaped the sliding faces into a dodecagon (12-sided polygon) to prevent saddle rotation. Parrett said it worked great, but after a few months of use, starting making a bit of noise. Now, they’re using a four-section keyed shape that, unfortunately, wasn’t on hand for visual inspection.

The internals are nitrogen charged and non-adjustable. But, the lever rotates a graduated cam, which depresses the release button gradually to give the rider fine control over the rate of drop and rise. The mechanism opens a valve, which moves oil from one side to another. When you release the lever, it cuts off flow between either side of the valve, and since oil won’t compress, it’ll stop at any point in its 5″ of travel and hold position. The nitrogen cartridge pushes it back up when it’s time to hammer. Nitrogen is used because there’s no moisture in it (versus air) so the internals won’t corrode, and it’s a bigger molecule so it’s less likely to leak.

Rotation and accidental drop are two of the most common problems associated with dropper posts, and Thomson’s taking large measures to ensure theirs won’t fail in either department.

“If you do what you’re supposed to do, it’ll last for years,” says Parrett. “But we have to figure out what riders are going to do that they aren’t supposed to. We’ve taken it through a car wash, driven in the rain at 80mph, tested it in -40°F to 140°F temps, and ridden it halfway compressed, among many others.

“That last one actually tore it up pretty good, which was a surprise. But something good to know before it got released.”

Right now, they’re on track for an April launch. One final change is that they’ll ship only with the remote cable actuated lever. Originally it was going to ship with that and the manual lever at the post, which could be swapped in with simple tools. But cost concerns and the fact that only about 10% of riders don’t use a remote meant it didn’t make sense to add cost for something most people aren’t going to use.

While we wait for that to hit shops, LH Thomson is already working on some pretty sick new versions and technologies…


They’ll follow up the regular dropper post with a stealth version that’ll flip the internals and use a hydraulic nitrogen-over-oil mechanism to reverse the cable pull into a hydraulic push to actuate the post. Goal is a June 1 release date.


A 27.2 dropper post is also in the works, which will probably be limited to 3-4″ of travel versus the 5″ of travel for the larger diameters. ETA is Eurobike.


“We got beat to market pretty bad on the mountain bike dropper post,” Parrett said. “But our road one will be the first of its kind.”

It’ll have various drop capabilities that are tuned for different types of rough road riding, using similar internals as the 27.2 mountain dropper post but with unique features.

“When we make the 27.2 mountain bike post, it’s only going to be a dropper post. Our road one will have that capability, but it’ll also have a “Pavé” setting that’ll drop it about 5mm and add a bit of suspension to take the edge off rough roads. The amount of suspension travel isn’t determined yet, but the rider will be able to fine tune when the suspension starts working. The plan for now is to only have it move about 2-3mm through its travel, but that could change after testing. The goal is primarily to reduce vibrations and make the rider more comfortable, which should make them faster and last longer in the saddle.”

They’ll do this with a dual action lever. Push it down and it’ll drop through it’s travel, push it up and it’ll switch to Pavé…but this design, too, is subject to change. They’re pretty early in the development process on this but have stated Eurobike as a release date. We could see a post mounted lever being a good option here, keeping the bike’s aesthetics cleaner.


From there, things get pie-in-the-sky, but Parrett says they’re actually working on a Bluetooth controlled circuit that can remotely actuate the post. One of the benefits is that it could potentially eliminate two SKUs (stealth and standard) for just one wireless remote version, eliminating the cable without sacrificing convenience…which is the ultimate goal. The immediate plan is to have a standalone Bluetooth switch that can be placed anywhere on the bike, but eventually they’ll have a smartphone app capable of controlling it.

By integrating the GPS, accelerometer and computing power of a rider’s smartphone, the app could automatically control the seatpost height based on incline/descent. Or, you could program it to learn a course and adjust the height based on location. No ETA on this, but they’re working on it.

NOTE: As I was finalizing this post, got word from Parrett that they just received the last of their test results and everything’s looking like production is set to start! We should have our hands on one before the April launch, so stay tuned for first impressions!


  1. How about they just focus on making it work correctly first? But I do like the idea of the wireless system though. Hopefully there’s no delay.

  2. Rivers – that’s why they kept working on it and did more testing. Most people we know aren’t riding with their weight on it for very long when the saddle’s down…dropping it (at least for us) is mainly to get the saddle out of the way.

  3. Yeah I understand that, but where I live in BC it’s nice to drop it just a little from climbing position and be able to pedal on the undulating terrain here….maybe this is why my KS post kept on failing….hmmm.

  4. So, did you ride the factory trail while visiting the esteemed Mr. Parrett? The trail sees a lot of local traffic and is a great after-work ride. Public thanks to LHT for hosting our trail building on their property!

  5. Smartphone app controlling a dropper post? Tell me they are kidding.

    Or maybe it will login to Strava and drop post in the beginning of a downhill segment identified by GPS?

  6. @Rivers: That is why my AMP and Gravity Dropper do have a 1″ lowered intermediate position. Both are working fine for three years now.

    Not as bling, not as light, but works.

  7. @ Mindless: Yeah I may just have to go that way since my KS had nothing but issues….I am just a whore when it comes to how my bike looks and I am not a fan of the aesthetics of those posts…as well I am a bigger dude and a bit scared of snapping them…lol.

  8. Maybe I read it wrong. They get all these parts from many different countries. Make the external parts here in the US, then ship them to Taiwan for assembly? Is this right? Is labor that cheap that they can justify sending parts from the US to Taiwan to have them shipped back to the US?

  9. I noticed a comment about writing it halfway compressed. That caught my attention that’s why I’m adding my two cents. I have been riding a gravity dropper for four years. I rarely write it in its most extended position, mostly one-inch down. For drops tight singletrack and downhill I drop it all the way. Infinite adjustments have their advantages but apparently fixed adjustments also do just fine and may stand the test of time a bit better .
    In four years I replaced my from activated switch once due to a crash and swapped out the cable twice. I take it apart about once a year for lubrication and inspection. The rubber boot tops off occasionally pops back on in a few seconds. When it does pop out from its resignation indentations it often becomes impossible to lock down in its lowest position. It will go there but not stay there. That’s what I know the boot popped off it’s time to dismount the bike spend 10 seconds and re-seat it.
    Good luck to Thompson and to anyone who hasn’t written a seatpost that is adjustable on-the-fly, in my opinion is the best upgrade you can make your mountain bike.

  10. Infinitely adjusted seat posts only being ridden with body weight at full extension, is that really want I am reading here? I have been riding said seat posts since the Maverick many years ago and have both KS and Reverb going now. I have never read anything that said to not ride with full weight unless at full extension on any of these posts. I never have read another review that said one should not ride with full weight other than at full extension. I do not know a rider that rides these seat posts not fully extended without full body weight at times. It is not at all about just getting the seat out of the way as a lower seat height with weight has application in the steeps, with exposure, etc. Even if it was, you cannot avoid the impacts that happen when in a down position. I have had durability problems with most of these posts and was really looking forward to the Thomson as they have made great products through the years. I still would love to catch the individual that stole my Masterpiece a couple of years back. I am going to try to ignore this report, hope that there has not been a philosophy change at Thomson and have faith they are going to ship a great product as they always have.

  11. Bluetooth wireless control would mean that you’d need to ensure that the battery is charged. That is 1 more additional thing to fiddle about which I think is not practical at all. We only need to drop the post when the front end starts pointing down. I think we can do away with all that bluetooth complication.

    LH Thomson, just make one where cable actuation is located same as the KS LEV and you can take my money.

  12. All – Just to clarify, the problem with riding the post midway through its travel was found DURING TESTING and corrected before production. The posts that will be for sale at your local bike shop can be ridden at any point in their travel for as long as you like without hurting them. Here’s the response from LH Thomson:

    Yes, the issue was found in ride testing, diagnosed and a manufacturing step was added. Full testing was done again, and the issue is solved. We have released the post to manufacturing.

  13. Rivers,
    I have broken my KS LEV twice in 6 months. Occasionally I will drop the saddle a couple inches to ride super techy rock gardens. Maybe thats why mine keeps failing…

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