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What is a dropper post?

Closeup of a PNW dropper post
(Image credit: OEM)

Among the many upgrades you could make to your mountain bike, there's one that almost any mountain biker would agree is key to unlocking more fun and less time wasted: a dropper post, but what exactly is a dropper post, and how does it work?

In this guide, we'll answer those questions and more, to help you make an informed decision about whether or not you want to invest in one, and which of the best dropper posts you might want to buy for your bike.

What is a dropper post?

Whether you're riding one of the best hardtail mountain bikes or the best full-suspension mountain bikes, it's undeniable that its most defining feature is its suspension. Having a telescopic front fork and, in the case of the latter, rear-suspension linkage is what helps you ride across the roughest of terrain, without getting bounced off the pedals or tipped over the handlebars.

The dropper post is another telescopic mountain bike component that makes as much of a difference to your mountain biking confidence as the best mountain bike forks or the best rear shock.

Effective as your suspension might be at keeping traction when rolling down rocky trails or rounding rooty corners, the truth is that a rider's weight distribution matters a lot. The average mountain biker is about seven times the weight of their bike and that means your body position makes a huge difference to stability and overall riding confidence.

The lower you can get when descending, the more control, traction and confidence you will have when riding. 'High-posting' is the colloquial term for riding with a seatpost at the fixed maximum height for general pedaling. It can make for a more difficult experience down any technical trail, and there is a reason that downhill mountain bikers have always ridden with very short seat posts.

dropper post

Many dropper posts are controlled with a remote lever on the handlebars (Image credit: OEM)

You often need to get that seat out of the way quickly when doing downhill 

The dropper post enables you to have the best of both worlds when mountain biking or gravel riding. It supports the rider at a correct seat height for climbing and general cadence but can drop by a significant margin at the touch of a lever, to place you in a better attack position when descending.

The dropper post is not a new idea. Ever since the early days of mountain biking, riders have been aware of a lowered seat post's potential for descending technical trails. For many years, the humble quick-release seat clamp was a DIY dropper post, but it required stopping, dismounting, and then resetting for climbs.

The manual quick-release dropper post wasn't too much of an annoyance for those riders who casually climbed to a long downhill trail section. But for any flowing trail, linked with short climbs, it was terribly impractical.

An adjustable seatpost that would mechanically return to its ideal climbing position was always the solution. Coil sprung options with mechanical levers mounted under the seat were some of the first true dropper posts, but they had limitations.

Packaging a coil spring into the seatpost is challenging due to space constraints. Having a release mechanism under the seat is also impractical since it required riders to take their hands off the bars.

The breakthrough happened with the launch of the RockShox Reverb dropper seatpost in 2010, which marked the start of the remote dropper-post revolution. Finally, there was a telescopic seatpost that would drop and return to position, with a handlebar lever, and controlled by a hydraulic trigger and air spring.

Since the Reverb, dropper seat posts have become standard fitment on all but the most lightweight XC bikes.

dropper post

Inside the DT Swiss D232 coil-sprung dropper post (Image credit: OEM)

Now there is a dropper for every riding style

As the demand for dropper posts has increased, so has the production of a generous range of sizes. Whatever amount of drop you need, depending on terrain and rider size, you are sure to find a dropper that will be perfect for your physiology or frame design.

From the best short-travel dropper posts that start at around 60mm to long-travel telescopic seat posts that can move more than 200mm of stroke, the dropper post is now indispensable for most riders. 

For XC racers, a dropper post helps them achieve a slightly lower center of gravity to navigate short and technical descents, while enduro riders can easily pedal uphill before triggering the dropper for a 15-minute black diamond descent. The remote-adjustable seatpost serves all.

An essential benefit of dropper posts, which often goes unrecognized, is how it has liberated frame design. Due to the dropper post, designers have created more daring geometries that provide good climbing balance and excellent descending stability.

How does a telescopic seatpost benefit the rider? It effectively gives you the best climbing and descending bike design in single-frame geometry. With the ability to radically alter seat height at a moment's notice, riders can use their body weight and posture to weight and unweight the bike into corners, jumps and over technical features.

dropper post

The remote-adjusted dropper post serves all riders of all disciplines (Image credit: OEM)

A more reliable solution

What is the future of the dropper post? Servicing can be an issue, as it must support rider weight when climbing while retaining low-friction properties to enable its stanchion to slide down the outer casing when triggered.

Bushing play can be an issue for larger riders on longer-travel dropper posts. This is due to the leverage pressure when riding along on bumpier terrain in the seated position.

There has been a return to the simpler coil-operated dropper post, especially for the shorter travel lengths. DT Swiss has proved the low-maintenance potential of this design with its D232, although that is a comparatively short-travel dropper, at 60mm.

For those mountain bikers who believe that an air-sprung dropper post gives the best feel and packaging, there is the technique of designing the frame to house a specific dropper post, when it is being made.

dropper post

PNW offers a range of travel-adjustable dropper posts (Image credit: OEM)

New design ideas 

Austrian brand Eightpins is a proponent of the integrated dropper post technique. It promises unrivalled reliability, but you'll need a frame manufacturer who is willing to factor the dropper post as an integral part of its design and production process.

The Eightpins design uses a mountain bike's seat tube as part of its structure, eliminating the need for a separate tube to slide into the frame. That means you can have a dropper with a slightly wider diameter structure, which does a better job of distributing load and preventing premature contact component wear, especially if you like running long-travel droppers.

One of the challenges for any rider selecting a dropper post is how much travel is needed. Most droppers are fixed at a specific amount of stroke, but PNW offers a range of travel adjustable dropper posts, like the PNW Rainier G3 post, thanks to a DU bushing. This empowers the rider to increase or decrease dropper-post stroke length, depending on riding style or frame shape.

In essence, the dropper post is a handlebar remote-triggered component that adjusts your riding height in seconds, allowing you to always be in the most stable possible riding position, whether climbing or descending.

Lance Branquinho is a Namibian-born media professional who graduated to mountain biking after injuries curtailed his fascination with trail running. He has a weakness for British steel hardtails, especially those which only run a single gear. Rides: Morewood Kwela Cotic Simple 26 Pyga 160mm aluminium prototype