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Item # THP0020

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  • Black, 30.9 x 400 ($450.00)
  • Black, 31.6 x 400 ($450.00)
  • Black, 27.2 x 430 ($450.00)
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Item # THP0020


While a foray into hydraulic systems may seem a stretch for Thomson, which has always made static parts, keep in mind the manufacturer is first and foremost an aerospace contractor. That means that, while it would seem that Thomson is starting behind companies like Fox and RockShox, who have been manufacturing hydraulic parts for years, Thomson is actually ahead of the learning curve—and the Thomson Dropper Post makes this point obvious.

The only part that the Dropper shares with its siblings is the much-loved saddle clamp. The post uses an oil cartridge to control height and a nitrogen shock to lift the mechanism. Because oil doesn’t compress, the post stays put wherever your posterior leaves it, for an infinite range of adjustment. The last 15mm of travel (at the top) is damped, so your body isn't on the receiving end of a hard smack.

  • Classic Thomson saddle clamp
  • Oil cartridge
  • Nitrogen shock
  • Infinite adjustability
  • Top 15mm of travel is damped
  • Handlebar remote and under-seat lever included

Tech Specs

[seatpost] aluminum
30.9 mm, 31.6 mm
400 mm
5 mm
125 mm
Recommended Use:
mountain biking
Manufacturer Warranty:
2 years
Actual Weight:
Black, 31.6 x 400: 507g

Reviews & Community

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Thomson Dropper Seatpost

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Here's what others have to say...

3 5

Installation issues!

  • Familiarity: I've used it several times

The cable included is too short. With the current routing it keeps getting caught in my pivots in the down position. Nothing like a seat that rises on its own.

5 5

Thomson Dropper Seatpost

I recently purchased this dropper post, so I haven't had it for a long time yet, but it seems to be working amazing so far!

5 5

Worth it.

  • Familiarity: I've put it through the wringer

I've used this post for over a year and haven't had an issue with it. Smooth up and down and easy to use/mount lever. Thomson quality for sure.

4 5

Pretty good, slightly sticky.

  • Familiarity: I've used it several times

I bought my Thompson 125 dropper post to replace a KS LEV seatpost that was spending months away at KS for a standard rebuild. Sick of waiting and longing for the ability to lower my seat, I shelled out for the Thompson. In two months, it's been great. No discernible play up or down or side to side. The seat remains tight and I have not had to adjust anything since the initial install. My only qualms so far is that the last 1 cm of travel is sometimes sticky when the seat returns. It is usually the first 4-5 times I use the post in a ride, and I have to manually pull the seat back up to full extension. I've heard of this happening with other Thompsons. Right now it a 4 star post. The first rebuild will determine if the rating goes up or down.

Responded on

Same just happened on my new post, sticks at the last 1 cm of rise. Under 30 day exchange so going for a new one.

Is this the v1 (short cable) or v2 elite...

Is this the v1 (short cable) or v2 elite dropper?

Responded on

It includes both sets of cables and housings. I have a large frame SC Tallboy and it small cable fit fine.

5 5

Best I've used so far

  • Familiarity: I've used it several times

While I haven't had this long enough to make a call on long-term reliability, I can say that it worked great out of the box, was easy to install, and has been flawless over the first month and ~200 trail miles in the PNW mud. Having used (and returned due to blown seals) a Reverb and KS Lev, this one has been the most pleasant user experience of the lot so far. The trigger feels great on the bar and fits well with shifter/brakes. Fingers crossed on reliability!

5 5

Beautiful piece of equipment

  • Gender: Male
  • Familiarity: I've put it through the wringer

Out of the box and installed without issue. Cable and housing length was spot on even for my XL Yeti ASR-7. Function is flawless so far and expect nothing but the best from Thomson. Will update as time goes on, but this is leaps and bounds better than my last dropper post.

4 months of use and still without an issue. I am also what most would consider a Clydesdale at 6'3" 240lbs geared up. I never have to think about it working or not working. If I don't have to think about a component, I consider it a win.

2 5

Play in the post after 1 month

  • Familiarity: I've used it several times

I'm 230 lbs, ~245 lbs with all my ride gear, and have been mountain biking for about two decades. Most of my riding in the past ten years falls into the all-mountain category. Out of the box, the Thompson post appeared promising. The post head makes saddle adjustments easy, and rock solid. Plus, the head/shaft machining is clean and bomber (I had problems on my old KS 950i post, where the saddle eventually spun on the seatpost shaft head). The handlebar lever is small, and required some trial and error to find the best ergo location on the handlebars. Strangely, Thompson shipped the post with a cable housing that was at least three inches too short for my frame (easily solved with spare housing I had on hand). Once installed, the seatpost adjusted easily, and had a rock-solid feel. Unfortunately, the post developed slop in the collar at the top of the fixed section of tubing (the part that stays inside the bike frame). After about a month of use, I could see several degrees of movement in the saddle and hear creaking during seated climbs. No post I've used so far has been perfect, but at this price, the Thompson shouldn't show this much wear in less than a season.

Responded on

I had the same problem. Called David at Thompson, he explained to me that the first run had a problem with this. He sent me a Newport and I have no problems since.