Vital MTB How-To: Choose a Mountain Bike Dropper Seat Post 15
Drop it like it’s hot!
It wasn’t all that long ago that dropping your seat on your mountain bike involved dismounting and operating a seat post quick release clamp. With the introduction of the first mainstream dropper seat post in the early 2000's, Gravity Dropper started what was soon to turn into nothing short of a revolution. Today, most if not all mid- to top-end trail, all-mountain, and enduro bikes will feature a dropper post as part of the original spec, and there are at least 20 brands to choose from. So how DO you go about picking one? That is exactly the question we’re just about to help you answer.
What is a Dropper Post and Why Do I Want One?
This will seem to many of you like stating the obvious, but getting your seat out of the way on technical descents, jumps, drops, turns, rough terrain and pretty much any combination thereof is a great idea. Put simply, riding is more fun with a dropper post. With your seat dropped at a press of a button, you are now free to move your bike around beneath you, which is a prerequisite to getting rad (unless you happen to be Nino Schurter in which case none of this applies).
Of course, unless you only ride park, you’ll be earning your turns at which point your seat needs to be back up again. Now take it to a trail which features a rollercoaster combo of ups and downs, and you’ll soon see why stopping to adjust your seat post every two minutes instead of doing it on the fly gets old very quickly. Think of the dropper post as your shred-mode switch:
To pick a dropper post, start with establishing how much drop you need. Typical dropper post travel ranges from 100 to 150mm, with even longer options now becoming more readily available. As a general rule, get as much travel as you can get away with. The lower you can get your seat, the more fun you’ll have, most of the time.
However, it’s not always quite that simple. You’ll want your dropper post to place your saddle at the optimum height for pedaling when fully extended. This means that your frame needs to a. have a low enough seat tube to accommodate the full collar-to-rail height of your chosen dropper post, and b. have a straight enough and long enough seat tube to accommodate the base of the dropper. If you find that a long travel dropper post will leave your saddle too high even when fully inserted into your frame, you’ll need to pick a dropper with less travel.
Similarly, if your frame features an interrupted seat tube or a pivot point that interferes with the base of the dropper, you may also end up having to get a shorter travel post.
In general, shorter travel posts are also shorter overall (i.e. including the base). Typical numbers are 340mm overall length for 100mm travel, and 440mm overall length for 150mm travel. With regards to post length, taller riders should make sure that the minimum insertion length will still leave them with enough seat post to achieve their desired maximum saddle height, especially if they ride a frame with a very low standover height. Also note that most dropper posts do not offer much in terms of setback, so if that criteria is important to you, it limits the choices on offer.
After you’ve figured out which length your dropper should be, make sure it’s available in a diameter that matches your frame’s seat tube. The two most common diameters are 30.9mm and 31.6mm, but there are several others (27.2, 34.9, etc). Don’t ask why the mountain bike industry still thinks it’s a good idea to keep working without a proper standard when it comes to seat post diameters, just accept it for what it is and make sure your frame is compatible with your chosen dropper. Note that in certain cases you may be able use a shim to fit a post to a frame with a bigger diameter seat tube, although not all manufacturers are happy with this solution (some claim it can put too much stress on the base of the dropper post).
Most droppers are operated with a remote on the handlebars, which means a connection of some kind is required to link the remote to the post itself (although some cheaper droppers still feature the control on the post itself, we certainly recommend spending enough to get a post with a bar-mounted remote, as it adds infinitely to the riding experience). The vast majority of today’s droppers use a cable-actuated mechanism, with two notable exceptions: the hydraulic remote-equipped RockShox Reverb, and the wireless Magura Vyron (soon to be joined by a Bluetooth operated post from KS and probably several others). Cables can be routed either externally or internally, the latter requiring a “stealth routing” compatible frame. Externally routed cables connect to the post either at the collar or at the head. Look for the posts where the cable is connected at the collar, as this allows for cleaner routing without any excess cable dangling around as you operate the post.
If your frame supports it, internal cable routing is a much cleaner option, although it turns the initial installation into a more involved procedure. If you intend to move one dropper between several bikes, you may be better off with an externally routed option – or an internally routed post with some form of quick-connect mechanism that can allow you to leave a remote and a cable on each bike, and just move the post back and forth.
A word on wireless: Magura was first to market with a wireless dropper post. The Vyron is a battery operated post controlled by a small wireless handlebar remote. Whilst this is no doubt the cleanest and easiest solution and one that holds a lot of promise, the Vyron currently features a bit too much operational lag to be really suited to proper all-mountain applications. Look for this type of technology to develop considerably over the coming years.
The remote is an important piece of the ergonomic dropper post puzzle, and one that may or may not have to compete for real estate on your handlebars. With the rapid evolution of 1x drivetrain technology, many riders are ditching the front derailleur which leaves a very obvious spot on the handlebars for the remote to occupy. This option works great with both shifter-style levers and other types of remotes (smaller thumb-levers or the hydraulic push-button of the Reverb).
If you run a front derailleur, you are probably best off with a dropper that features a smaller, thumb-operated lever. This can typically be installed right next to the grip, and some manufacturers provide remotes that can even take the place of the inner lock-ring of your grips for that extra clean look (certain shifter-style remotes will also integrate with single-clamp brake lever/shifter set-ups, such as the iSpec standard from Shimano).
The RockShox Reverb remote is unique, since this is the only fully hydraulic post on the market today. The small remote unit exists in both left- and right-hand side options, with the run-the-right-hand-remote-upside-down-on-the-left option the most common choice among the 1x crowd. If you happen to be running SRAM brakes, the brake lever perch will also integrate nicely with the clamp of the Reverb remote.
One of the benefits of a dropper post is the ability to fine-tune your seat height on the fly, not just slamming your seat down as far as it will go. For example, when attempting a tricky technical climb, you might find that dropping your post just a fraction of the total available travel will provide enough room for you to move around while still offering a tall enough seat to rest on while pedaling. The majority of today’s posts feature infinite travel, meaning you can stop the seat anywhere you want within the overall travel available. Some posts feature preset positions within the travel, which may allow you to find that particular sweetspot a bit easier. It is up to you to decide if this feature is important to you – we find that we are able to stop our post where we need it to be most of the time even with the infinite travel options, and we consider it an advantage to be able to choose freely.
Locking Mechanism and Spring
Since a dropper post needs to return to full height by itself, all dropper posts feature some kind of spring mechanism. The most common type is the airspring, but mechanical springs are also used. Airsprings can be made quite light, and often offer the advantage of being able to help change the return speed of the post (by varying the pressure), but they can also be more prone to failure and costlier to maintain.
When it comes to the locking mechanism, we are talking about possibly the most critical feature of a dropper post and certainly the most often cited source of user despair regarding failures. Sadly, for all the enjoyment we get out of our dropper posts, reliability is still the elephant in the room and an issue that plagues almost every post at some point.
The locking mechanism or brake is what holds the dropper post in a given position. Many posts use a hydraulic cartridge with a port that shuts off the oil circuit to stop the mast from moving. Whilst this provides for very smooth operation, it is also prone to failure. When the seals wear out for example, air can get introduced to the oil side, which causes the locking mechanism to be less solid. You’ll notice your seat post sagging under your weight even though it’s locked. On some posts, the brake only works in one direction, meaning that the seat post will extend if you try lifting your bike by the saddle. A minor annoyance for some, a deal breaker for others. Some posts will allow you to continue to set your saddle height manually even if the spring fails, which can make all the difference if you have problems far from the trail head. Mechanical brakes would seem the obvious solution, but we have yet to come across a faultless implementation. The jury is still out on which mechanism is best, and we’ll have a forth coming group test to attempt to clarify this matter in the coming months. In the meantime, pick a post and cross your fingers…
Dropper posts typically weigh in at around 600 grams including the remote (for 125-150mm of travel). It is possible to find lighter options, and some droppers are a bit heavier. In either case, you are still accepting a weight penalty over a classic fixed post, but one that we would gladly live with even it was double what it is now. Of course, all other things being equal, a lighter post would generally be considered a better post, since most people do try to shed a bit of weight off their bikes at some point, and with a variance of 250-300 grams between the lightest and the heaviest droppers currently on the market, this aspect is worth considering when choosing your new dropper. Note that the manufacturers do not all weigh their posts in the same way (with or without remote, shortest available length etc).
Naturally, as with most things mountain biking, the lighter stuff gets, the more expensive it gets. That’s generally sort of true with dropper posts as well, although there are some recent entries to the market that seem to somewhat defy convention here. Our upcoming group test will determine what’s what, but in the meantime, expect to pay anywhere between $300 to $450 for a good dropper with a reasonable weight.
There are several more points to consider when choosing a dropper. Some of these may be more or less important to you, but still something to keep in mind when evaluating a new post.
Cold Weather Performance
Hydraulically activated posts are particularly affected by cold weather, which leaves the remote feeling a bit stiff. Cold weather can also affect the performance of the post itself, so if you live in areas with cold winters you should look for a dropper that specifically addresses this issue.
As you’ve probably gathered by now, the reliability of your new favorite bike part is not quite what it’s meant to be, at least not quite yet. That means that you should probably choose a post that is easy to maintain, and for which parts and service are readily available. Not all posts are user serviceable, while some use a fully closed cartridge that is just meant to be replaced when the time comes for service. Some now offer an easy-to-access air valve for topping up or adjusting the air pressure, while others require you to remove the saddle to access it.
A quick connect mechanism at the base of internally routed posts will be very helpful when the time comes to take your post to the shop (not taking your whole bike to the shop for parts service is a great way to win favor with your grumpy LBS wrench). On that topic, solid warranty is always nice to have, particularly on parts this prone to failure.
So, Which Post Should I Get?
If only it were that easy! There are at least 20 viable options currently in the dropper post market, and finding the right one for you may be a bit more involved than you think. We’re currently working on a major group test to figure out which are the best droppers in the game today, but until that is ready, here is an overview of most of the contenders (note that the weights are only indicative, since the manufacturers do not weigh their posts in a consistent manner):
KS Lev Ci
The KS Lev series has long been held in high regard, now it is the first to go carbon mast for a serious weight saving.
RockShox Reverb Stealth B1
Standard OEM spec on most trail/AM/enduro bikes today, a proven performer that just got a major overhaul. One of the first to offer a 170mm travel option.
FOX Transfer Factory
FOX took a long time to replace their DOSS post, one of the most reliable in the world (but heavy and featuring a nasty remote). The Transfer looks to continue the reliability tradition in a much more up-to-date post.
Race Face Turbine
Race Face licensed the internals from 9Point8, a small Canadian company. The first generation can be finicky to set up and has had some reliability issues, but when it works, it's very good. We're about to test the revised version to find out more. (Also sold as the Easton Haven).
9Point8 Fall Line
Offering great reliability and cold weather performance, 9point8 flew under the radar for a while, but their posts have a loyal following. One of the first to go beyond 150mm travel. The Fall Line technology is licensed to Race Face and Easton for their Turbine and Haven dropper posts, respectively.
Giant Contact SL Switch
Recently updated, the Contact SL Switch offers good performance at a great price - and it allows you to easily switch between internal and external routing on the same post. It exists only in the 30.9mm diameter, but you should be able to shim it for larger seat tube.
Bontrager Drop Line
Another recent entry, Bontrager's Drop Line is only made in Trek's standard 31.6mm seat tube diameter. If this suits you, you're in luck, since it offers good specs and performance at a great price.
e*thirteen TRS+ Dropper
e*thirteen took their time entering the dropper post market, and they have come up with something a bit different. With a mechanical spring and locking mechanism, they are aiming for max reliability (at an awesome price too!). We are currently testing it to see how it performs in the real world.
Thomson was always the gold standard in regular seat posts, so it's no wonder they took their sweet time coming up with a dropper worthy of their name. With nothing but top-quality components and a sturdy construction, Thomson went all in at the reliability table. We're testing one to see if they succeeded.
DVO only just released the Garnet now. They've aimed for top-notch reliability, with a mechanical spring assisting the main air spring and to provide backup in case of failure. We'll put some miles on this one to see what that translates to.
BikeYoke are known for coming up with clever solutions, so chances are their dropper will work well too. We'll find out when it hits the market in early 2017.
X-Fusion Hilo Strate
X-Fusion's Hilo Strate comes in at a great price, but slightly on the portly side. The Manic post holds more promise at a price point defying all current competition, but that one currently lacks the travel options to be fully competitive.
PNW Components is a small, rider-owned company. The Bachelor is their first 150mm offering, which looks to offer reliability in a lightweight package.
Magura Vyron eLECT
The first wireless dropper in the world had us quite excited at the prospect of not having to faff around with internal cable routing (the bane of any wrench's life). Sadly, it has failed to live up to performance expectations with notable lag between pressing the button and the post activating. We're hoping the 2nd generation will deliver!
The dropper that can rightfully be credited with launching the whole dropper post craze is fittingly known as the Gravity Dropper. It may seem a little outdated by now, even in the most recent Turbo LP version, but its 100% mechanical construction and ease of maintenance are still winning over new buyers today.
Ritchey Dropper Post
Ritchey's first entry into the dropper post market features a mechanical, 3-position construction which is said to be highly reliable, but it falls a little short on travel.
The Highline is the post charged with restoring Crankbrothers' reliability reputation after the Joplin failed quite miserably in this regard. We're currently long-term testing one to see how it stacks up.
Specialized Command Post IRCC
Specialized makes several dropper posts of its own, the Command Post IRCC (short for Internally Routed, Cruise Control) features 10 present drop positions and an offset head.
Gravity (FSA) Dropper
Gravity's dropper is competitively priced but comes up short in the travel stakes, and comes in on the heavy side. Gravity is now fully integrated into the FSA brand.
Nukeproof's OKLO is also competitively priced, but heavy and a bit short on travel.
The Manic looks like one of the potential value winners at a very low MSRP, but we'd need to see more travel options for it to truly contend.
PRO Components Koryak
PRO (which is owned by Shimano) only joined the dropper post party in 2016, and their first offering is perhaps a little underwhelming with just the one, short-travel option available.
KS Lev Circuit
All we know is that if KS can deliver a wireless experience anywhere close to their current wired options, this will be a seriously sweet option. Time will tell as we have yet to see any of these in the wild.
Eightpins' integrated offering is intriguing, to say the least. It uses the frame seat tube in a new way, which drops weight and allows the company to offer more travel. On the flipside, it requires a custom frame. Liteville is the only frame maker to offer Eightpins integration today, let's see if others follow in 2017.