How to choose a dropper seatpost?

The dropper seatpost has become an essential MTB component, not just for aggressive riding. The advantage of the dropper seatpost? It allows you to lower and raise the saddle easily without having to dismount. You can drop the saddle as you approach a technical section to gain manoeuvrability and riding comfort. A press of the lever returns the saddle to its original height and ideal pedalling position.

Probikeshop helps you here to choose the right dropper seatpost.

All the criteria for choosing the right dropper seatpost

Before choosing the brand and the right model, you need to check a few compatibility points:

Next, you can review the characteristics of your dropper seatpost:

How to choose the right diameter and length?

The choice of seatpost dimensions depends directly on your frame, your build and your pedalling position.

Your frame will easily give you the correct diameter: it naturally corresponds to the inner diameter of the seat tube. Be careful not to confuse the seat tube diameter with the seat clamp diameter.

To determine the correct length, you need to take several factors into account:

The idea is simple: the seatpost must reach your reference height when fully extended using its full travel, without conflicting with your frame (due to an insertion that is too short or too long in the seat tube). Smaller frames can in particular limit your choice of dropper seatpost. A simple calculation allows you to determine the maximum length you can aim for:

The result of (total seatpost length + cable/hydraulic connector height) must not exceed the measurement of (your usual saddle height + maximum insertion length).

Manufacturers always indicate the minimum insertion level to be respected on the seatpost, for safety reasons.

How to choose the travel?

The choice of travel depends on the total length of the dropper seatpost, and vice versa. Travel ranges from approximately 50 mm to 200 mm.

Brands exploit this travel in 2 different ways: with a "continuous" or "stepped" ("indexed") mechanism. The continuous mechanism offers infinite adjustment over the available travel, while indexed positions offer pre-defined positions.

While partly constrained by your frame's geometry/size, the choice of travel remains determined by your MTB riding style. Smaller amounts of travel are generally recommended for Gravel or Cross-Country use. The longest travels are better suited to Enduro models and larger MTBs.

Be careful not to confuse the travel of a dropper seatpost (the distance over which the saddle can move up/down) with the travel of a suspension seatpost (the vertical movement of the suspension).

Cable, hydraulic or electronic mechanism?

The telescopic mechanism is actuated hydraulically, mechanically or electronically.

The most common connection between the lever and the seatpost remains the cable model, which is simpler to maintain. The hydraulic lever uses a hose and oil, which means bleeding the circuit when the lever starts to feel spongy. Finally, the electronic version offers the most efficient operation and the cleanest setup (wireless). It eliminates the physical connection (cable or hose) as well as any issues related to routing or maintenance.

Which lever to choose?

Which lever to choose?The dropper seatpost is operated by a lever, most commonly mounted on the handlebars. A few entry-level models have an integrated lever under the saddle. This configuration has the advantage of making fitting and maintenance easier, but using it at full effort is more complicated.

Be aware when choosing your new dropper seatpost that the handlebar lever may be included or sold separately. Manufacturers increasingly offer the lever as an optional extra, to allow you to adapt the setup to your cockpit.

If you choose your lever separately, you need to check the following points:

Internal or external routing?

The cable or hose routing is determined by the characteristics of your MTB frame. You will always find dropper seatposts for external cable routing – the fitting is visible on the mid-section of the post or under the saddle. When the cable runs inside the frame, the fitting is hidden at the base of the seatpost.

With or without setback?

You have one final choice to make: should you opt for a straight dropper seatpost or one with a slightly set-back saddle carriage?

A dropper seatpost with saddle setback can help correct your position. Be careful, however, as setback affects not only your position relative to the handlebars, but also relative to the bottom bracket. If you are too far back, you risk losing control more easily as you unweight the front. You may also struggle to develop your full pedalling power.