Buyers guide to dropper seatposts

thomson elite dropper postThey go down. They go up. Here’s what else to look for in a dropper seatpost.

Dropper seatposts are one of the greatest cycling innovations of modern times. Although variations of them have been around for a good number of years it’s only really in the past two or three years that they’ve become a common sight on bikes.

They are still relatively expensive items but you’ll struggle to find anyone who’s bought one who doesn’t say that a dropper post is one of the best things that they’ve bought for their bike.

Why are dropper posts so good?

They make riding more fun. And fun is what it’s all about.

Being able to get the saddle out of the way on-the-fly is a real game-changer.

No more hanging off the back of the saddle on descents and impairing your bike control. You can get your centre of gravity low down and central, where it should be.

No more being mildly battered as you try to hover over the saddle when pedalling over lumpy traverses.

And – most significantly – no more having to stop, get off, fiddle with seatpost QRs. Hurray!

Once you’ve ridden with a dropper post you’ll never want to go back to static post ever again.

How do dropper posts vary?

Most dropper posts these days are remotely operated by a switch on the handlebar. There are still some designs that use an under-the-saddle-nose grab-lever but these have fallen out of favour because it’s simply so much better (and safer) to be able to operate the seatpost from the bars.

The majority of dropper posts offer 125mm of drop. There are some that only offer 100mm – which is good for smaller riders. There are a few that offer a whopping 150mm of drop – good for tall riders who tackle extreme terrain.

The cabling system will either be hydraulic hose (like a disc brake) or cable-actuated (like a gear cable inner and outer). There are pros and cons to each.

Hose or cable?

Cable-actuated systems can offer great levels of feel and accuracy but they will be prone to dirt and water ingress. You also need to route the cabling carefully so as to avoid tight bends which will cause excessive friction in the cable actuation.

Hydraulic cable (like on the market-leading RockShox Reverb) can feel a bit vague or imprecise compared to a well set up cable-actuated system but it is sealed against the elements and is much more tolerant of circuitous cable routing.

Most dropper posts offer infinite height adjustment ie you can leave the post at any setting in its travel and it will stay there. If you’re going to want to set the seatpost to such a mid-point setting frequently then consider getting a cable-actuated dropper post – they’re usually more precise than hydraulic hosed posts.

Remote control

The actual remote control lever on the handlebar varies in design too. Some hydraulic cable posts have a plunger style ‘long button’. Cable-actuated designs vary from large push-push twin-blade levers or minimalist rocker levers or pivoting-pushrod ‘floating socket’ designs.

rockshox reverb stealthDropper posts differ in feel and speed of operation ie some compress and extend slower – or have a more damped motion – than others. A lot of dropper posts offer the ability to adjust the speed of re-extension. Check the post’s specification list.

Internals, clamps and diameters

The internals of dropper posts do vary but you don’t need to know much about the specifics of each design. They are fairly complex (like the insides of a suspension fork). Some are more home-serviceable than others (Thomson’s Elite Dropper post is a good example).

As with static seatposts, dropper posts can come with inline clamp heads or layback clamp heads. These days saddle rails offer enough adjustment to cope with either clamp head style but it’s something to be aware of if you currently have your saddle positioned at the extremes of its rails.

And obviously you need to make sure you buy the seatpost that fits your frame’s seat tube. 30.9mm and 31.6mm are the common sizes of dropper posts. If you’re unsure of your seatpost size, simply remove your existng seatpost and there should be a number written on it somewhere.

Stealth

Some dropper posts are available in ‘stealth‘ versions. These are designs where the hose/cable enters the very bottom end of the seat post (rather than the normal desing where the cable enters the post at the head clamp end.

Stealth designs do not fit all frames. They only fit frames that have specific stealth routing ie a purpose-made porthole in the seat tube usually just above where a front mech clamp would be.

If you have such a frame you’ll know this already. If you’re not sure, then you almost certainly do not have a Stealth-compatible frame.

Which dropper seat post should you buy?

Casual riders should consider dipping their toes in to the world of dropper posts. They can often be the one component that helps a rider progress faster and further than any other. The best bet is to buy based on price. Stick to a sub-£200 budget. Go for a 100mm travel post if you find one cheap enough.

Regular riders should go for a dropper post with a hydraulic hose actuation and 125mm of travel. Most of us weekend warriors only run the post in two settings – fully down or fully up – so there’s no need for the micro-feel of a well set up cable actuated system. The weather-proofing and less finicky cable routing will be more important and valued.

Enduro racers may think about a cable actuated post. Although such posts can look like they’re a bit agricultural (we like our hydraulic hoses us mountain bikers) cable actuated posts offer high levels of feel and control and speed-of-operation. Racers also won’t mind having to keep an eye on and service/maintain the cabling in return for improved performance during racing.

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