Group test: Dropper seatposts
Group test: Dropper seatposts
Dropper posts are primarily for getting the saddle out of the way on off-road descents so you can ride technical terrain more easily. However, being able to drop your saddle also makes a huge difference to the ease of mounting and dismounting the bike.
All droppers are heavier than a standard post. Most riders who use one think that is a small price to pay. While dropper levers are usually designed for flat bar MTB use, you can get drop bar levers. In terms of maintenance, try to keep the post clean. Protect it with a mudguard if you can. Many dropper problems are caused by the cable so change it regularly.
Droppers have been around for a good few years now, and are considerably more reliable than they were even five years ago. Most will nevertheless fail at some point. Many can be serviced, some by the home mechanic. For others, the cost of a service can be almost as much as a new post.
Reverbs have been around for a long time. This latest offering includes a shorter post length, so it should fit into more frames. It also includes a vent valve to help with servicing. This is the only hydraulic post in the test and it’s the messiest to fit; a bleed kit is included. In action it has a good, smooth feel, and return speed can be easily adjusted. Only time will tell if Rockshox has cured the high failure rate of earlier Reverbs. Diameter: 30.9, 31.6, 34.9mm. Travel: 100, 125, 150, 175, 200mm.
Smooth, hydraulic post with a chequered past for reliability.
X-Fusion Manic 150 £220
This only comes as an internally routed post and is only available with a 1× lever. The cable is routed from the bar, which makes fitting the post more fiddly. In use the Manic 150 has a good solid feel to it, and it moves smoothly. The lever also has a good feel, and because it is on a ball socket is easy to adjust to precisely where you want it to be – a nice touch. Service kits and new cartridges are (in normal circumstances) available for long-term maintenance. Diameter: 30.9, 31.6, 34.9mm. Travel: 150mm.
Works well, feels solid, with an easily adjustable lever.
PNW Rainier Gen 3 £131.69 plus lever
You'll need to add a lever when you buy this post, unless you have one already. I tested it with PNW’s 1× Loam lever (£50). The post has an unusual feature: an adjuster under the collar provides up to 30mm travel adjustment. The Rainier Gen 3 has a good solid feel in use, more so than the Brand X, and the Loam lever works well. Post and lever are straightforward to fit. Big thumbs up for a 3mm bolt instead of a tiny grub screw! Diameter: 30.9, 31.6mm. Travel: 125, 150, 170, 200mm.
Works fine and is exceptionally easy to fit to the bike.
Brand X Ascend II £140
Brand-X is effectively Chain Reaction’s house brand so, as you’d expect, the Ascend II is competitively priced. Being externally routed, it’s easy to fit. It comes with a 1× or a 2× lever, and in a wide range of sizes and drop lengths. I tested the 125mm. The post is actuated from the collar, which keeps the cable out of the way neatly. All droppers have some lateral movement but this post seemed to have more than most. It still goes up and down fine. Diameter: 27.2, 30.9, 31.6mm. Travel: 105, 125, 150mm.
A basic yet functional dropper at a very good price.
The cheapest post here, the Brand X Ascend II, also felt the least sturdy but it’s nevertheless a functional and (for droppers) an inexpensive option.
Reverbs are expensive and, from my experience with them as a mechanic, still feel like a gamble. When they work, they do feel lovely.
The X-Fusion and the PNW are comparable in terms of solidity and smoothness but I far preferred the ease of fitting of the PNW over the X-Fusion. Running the cable from the post to the lever makes more sense and makes fitting much easier. PNW also deserve extra points for the well-designed Loam lever.
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Dropper seatposts: what to look for
1. Seatpost diameter
This has to match your bike’s seat tube (unless you use a properly engineered shim). The most common sizes are 30.9 and 31.6mm, but 27.2 and 34.9mm are available. Keep a rigid post as a backup.
2. Internal or external routing?
Most good quality, modern mountain bike frames will have internal cable routing for a dropper post, but do check. If not, you’ll need a dropper with an externally routed cable. Also, see point 4.
3. Max extension
How far the post comes out of the frame when the post is extended. This needs to be high enough for you to have your saddle at the correct height when seated and pedalling – but not too high! You can then work out what height of drop (100mm, 125mm, etc) that you can run.
4. Minimum insertion
It needs to be able to go deep enough for the actuation lever on the bottom of the post to work freely (internal droppers only). If your frame has a kinked seat tube you might not be able to get the post in far enough.
Check that you get a lever with the post – this isn’t a given. Most set-ups cater for a 1 × system so if you are still running a front mech, check you can get a 2× lever. Aftermarket levers are available from many manufacturers.
Some seatpacks work with dropper posts. See Alpkit Koala Exo-Rail seatpack review.