Mountain Bike Dropper Posts (A Complete Guide)

One of my favorite things about mountain biking is the fact that there is always something to improve on. You can spend years honing your fitness or working on your technical skills. There are always improvements to be made, which makes the progression in this sport seemingly limitless.

Sometimes, improvements can be as simple as upgrading equipment. Dropper posts have become increasingly popular in recent years and I’m a huge advocate. In just a few rides, my dropper post completely revolutionized the way I descend on my mountain bike. 

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What is a Mountain Bike Dropper Post?

A mountain bike dropper post is a telescopic seat post that can raise and lower with the touch of a button. In the raised position, the saddle is at the optimal height to allow you to pedal efficiently. When you are ready to descend, you can lower the saddle so that it gets out of your way. This allows you to better lean the bike when cornering and it allows you to more easily shift your weight backwards without risking getting caught on the saddle.

Do You Need a Dropper Post?

Originally, dropper posts were most common amongst riders who focused on descents such as downhillers or enduro racers. As technology has improved, and the benefits of dropper posts have become widely recognized, more and more mountain bikers are adding dropper posts to their rigs. In fact, dropper posts have become commonplace in the cross country world cup racing scene. It seems that every rider can benefit from a dropper post.

What Type of Rider Can Use Benefit from a Dropper Post?

Any mountain biker can benefit from having a dropper post. Advanced riders can utilize a dropper post to increase speed and tackle even bigger and steeper obstacles. Intermediate and beginner riders will benefit from a dropper post because it will increase confidence and make riding with proper form and technique come more easily. In fact, many skills clinics will ask riders to lower their saddles for the duration of the clinic if the riders don’t have a dropper post.

What Type of Bike Should Have a Dropper Post?

Downhill bikes, enduro bikes, and trail bikes will almost always have dropper posts on them now-a-days since the primary focus on those bikes is the ability to descend with speed. Downhill and enduro bikes will have longer dropper posts because it allows you to get your saddle further out of the way on more technical trails. Weight is generally not a concern for these types of riders so there is no reason to skimp on dropper post length.

Cross country bikes won’t always have a dropper post, but can definitely still benefit from one.  While many people think cross country bikes are primarily built to climb, cross country bikes can still have an incredible ability to descend which can be amplified with the addition of a dropper post. Cross country bikes will have shorter dropper posts in order to find a compromise because riding efficiency, body position, and weight of the dropper post.

What Type of Terrain is Best for a Dropper Post?

The gnarlier the terrain, the more important a dropper post will be. Dropper posts are hugely beneficial for steep terrain, drops, and jumps when you need the saddle to be completely out of the way.

When to Use Your MTB Dropper Post?

Dropper posts are ideal for quick terrain changes in which you need to be able to move from seated to sanding quickly. They allow you to be more agile on the bike, without getting hung up on the saddle when you shift your weight. Here are some of the best times to use your mtb dropper post:

Cornering: Dropper posts are very helpful for fast cornering because it allows you to get lower and lean the bike further without the saddle hitting your leg. In this way you are able to lower your center of gravity and find better traction through the turns. 

Steep Descents: Dropper posts make a huge difference when tackling steep descents. The other day I was struggling with a challenging rock roll-in and then I realized I had forgotten to lower my dropper post. Once I lowered my dropper post, I could get lower and further back behind the saddle and easily attack the steep descent.

Jumps/Drops: You’ll want to lower your dropper post for jumps and drops because you’ll be able to move and adjust more easily in the air without the risk of getting caught on your saddle.

Steep Obstacles: You may even use your dropper post for steep uphills such as pitches or steep and tight switchbacks. When the saddle is out of the way, you can be more agile on the bike and move it however you need in order to work your way up and over the obstacles.

Can You Upgrade Your Mountain Bike with a Dropper?

Yes! Dropper posts are often an upgrade that you will make on your bike. While downhill or enduro bikes will likely come with a dropper post, cross country bikes may require you to make the upgrade. Additionally, you may wish to trade in whatever dropper post comes on your bike for a better, lighter, or more reliable dropper post. Almost all bikes will allow you to add a dropper post, although it will be important to understand what posts are compatible with your bike.

Where to Purchase a MTB Dropper Post:

Local Bike Shop: Your local bike shop will likely have a couple of dropper posts in stock, but they may or may not be exactly what you are looking for. Most bike shops will be able to order your ideal dropper post and even help you with the installation. This may be a slightly more expensive route to go, but it can be very helpful to have an expert help you with selection, fit, and install.

Online Retailers: You can also purchase a dropper post from an online retailer such as Competitive Cyclist, EVO.com, or JensonUSA.com. If you know exactly what you are looking for this will likely be your most convenient purchasing option and may even have the fastest delivery time.

Bike Swap/Used: If the price of a dropper post has you hesitating then you can always purchase used. Cyclists are known for their constant upgrades so it’s likely that your local cycling group or online forum will have one for sale. When purchasing the post used, make sure that the stanchions aren’t scratched, and check functionality.

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Considerations for Selecting a Mountain Bike Dropper Post

Seat Tube Length: First, look up your bike and see if the frame specifies a seat post insertion length. In other words, you need to know how long of a seat post your seat tube can accommodate.

If your bike frame does not clearly specify the insertion length, you’ll need to measure it yourself. You can measure it by using your current seat post. Carefully insert your current seat post into the frame and see how far you can insert the post before it is limited. Mark the post and measure the length of seat post that you were able to put into the frame.

Once you know the seat post length that your frame can accommodate, you’ll need to find a dropper post that advertises that insertion length. The work doesn’t end there though. Just because a dropper post can fit into your bike frame, doesn’t mean it will work with your saddle height.

When you look at dropper post diagrams online you’ll notice that there is a minimum and maximum insertion length. You’ll need your saddle height to fall somewhere in between that range when the dropper post is fully extended.

For Example: Let’s say that your dropper post is 100 mm. You will need your optimal saddle height to be 100 mm + the amount of seat post exposed once the minimum or maximum insertion length is met.

Seat Post Diameter: The next thing to consider is the seat post diameter. The most standard seat post diameters are 27.2, 30.9, 31.6 mm. Make sure that the dropper post you purchase matches the diameter that your frame accommodates.

Dropper Post Drop: You’ll need to decide how much you actually want your dropper post to drop. You may be limited in your options depending on your frame and seat tube length as described above. Dropper posts generally range from 100-200 mm of drop.

Cable Routing: If your frame has internal cable routing you’ll likely want an internally routed dropper post. However, if you have a bike without internal cable routing then you’ll need to make sure you purchase a dropper with external routing.

Wireless: Wireless dropper posts are also available. Wireless dropper posts will be cleaner without cables and will be easier to add and remove. They will also require little to no maintenance in comparison to a dropper post with cables. Wireless dropper posts are usually more expensive and will require you to charge them every now and then.

Weight: Dropper posts are generally heavier than a standard seat post, therefore, when you select your dropper post you’ll want to take note of how much weight you are adding to your bike and where the cost verses benefit stops for you.

Lever: You will also need to decide what type of lever you want to have on your cockpit in order to operate your dropper post. You can select a 1x push lever that will go under the bar or 2x level if you have limited space in your cockpit.

How to Install an MTB Dropper Post

Every dropper post style will have different installation steps and tips. I highly recommend letting your local bike shop install your dropper post the first time. However, if you’re a do it yourself kind of person there are lots of videos available online.

Here are the step by step instructions for how to install a Reverb AXS Dropper Post.

Tools Needed:

Installing the Reverb AXS Dropper Post is fairly simple and only requires a few tools, that if you are already pretty handy with your bike, you might have on hand anyways.

• Allen Key Set
• T25 Torx Tool
• Tape Measurer
• Torque Wrench
• Matchmaker or Clamp (depending on braking system)

When you unbox your Reverb AXS you’ll find the following items:

• Post
• Battery
• Remote/Controller
• Charger

Installation Steps for a MTB Dropper Post (numbered with description)

1. Secure Your Bike: Put your bike in a safe location, on level ground. Since most bike stands clamp to the seat post, you likely won’t be able to use your stand for this.
2. Measure Your Current Saddle Height: Using a tape measure, mark a spot on your saddle that is 12 mm from the back. Now measure from the mark to the center of the crank spindle. That number is your saddle height.
3. Measure Your Saddle Setback: Using a tape measure, measure from the tip of the saddle to the center of the bars.
4. Remove Your Saddle: Remove your current saddle from your current seat post. You will do this using the Allen Key set to remove the seat bolts from the seat rails.
5. Remove Your Post:  Use the Allen Key Set to loosen the bolt on your seat collar. Once the bolt is loose, gently slide out the seat post. Note: You should not fully remove the bolt or seat collar.
6. Install Your Saddle: Place your saddle onto the Reverb AXS Dropper post by sliding the rails into the seat post clamp and using the Torx Tool to tighten the bolts. Note: You will adjust the position of the saddle once it is on the bike. 
7. Install Seat Post Into the Frame: Slide the seatpost into the frame and use the Allen Key to tighten the bolt on the seat post collar.
8. Install Remote: This step will vary based on whether you have a Shimano or Sram braking system.

a. Sram Install: If you have a Sram braking system, then you will use a matchmaker to install the remote. Remove the brake, and install the matchmaker to the clamp on the brake by bolting the matchmaker to the brake with the nut and bolt that comes with the matchmaker system. Bolt the remote to the matchmaker. Reinstall the brake lever to your bar.

b. Shimano Braking System Install: If you have Shimano brakes then you will use a clamp to mount the remote to the bar, separate from the brake lever, on the left side. Place the clamp around the bar, and tighten down the bolt to secure the clamp. As you tighten the bolt through the clamp, place the remote on the backside of the clamp and line up the bolt with the hole on the shifter to secure the remote to the clamp.

9. Level Saddle: Use the bolt at the top and front of the seat post to adjust the nose of the saddle.

10. Set Saddle Position: Loosen the saddle on the rails just enough so you can move the saddle forward and backwards. Additionally, loosen the bolt at the collar of the frame. Now, using the measurements that you took from steps 2 and 3, set your saddle height and position. Note: You need to set these measurements simultaneously because the height and set back will both influence each other.  Once the saddle and post are in the proper positions, use your torque wrench to tighten the bolts to spec.

11. Install the Battery to the dropper post: Use the small clip to secure the battery in place.

12. Pair the Dropper Post and Remote: Press and hold the button on the dropper post until it starts to blink. Let go of the button. Press and hold the button on the remote until it starts to blink. Let go of the button. Tap the button on the remote and the dropper post so that they both stop blinking. Your post and remote are now paired.

13. Test the Post: Press the remote and push down on the seat to make sure that the dropper post is functional.

14. Go Ride!

Post-Installation Tips:

Once you put on your new dropper post for the first time, there are a few new rules you’ll want to follow to protect your dropper post and gear.

Don’t Lift When Collapsed: If your dropper post is pushed down or collapsed, don’t lift or hang the bike by the saddle. Hanging or lifting the bike in this position can damage the internal mechanics of the post. Simply raise the saddle before lifting or hanging your bike.

Wash Your Bike With The Dropper Up: When you wash your bike, make sure the dropper is up. You want to make sure to wash the stanchions, otherwise you risk dirt and grime getting stuck in the seals and scratching the stanchions.

Check Your Saddle Bag Clearance: If you normally ride with a saddle bag, you’ll want to make sure that the bag still has clearance when the saddle is down, and the suspension is compressed. The last thing you want is your saddle back getting ripped up by the rear tire.

Maintenance Tips for Dropper Posts:

Once your dropper post is installed there shouldn’t be too much maintenance involved. Just like the rest of your bike, you’ll want to keep it clean so that grime doesn’t slow down or inhibit function.

Wireless Dropper Posts Maintenance: One of the benefits of having a wireless dropper post is that there is very minimal upkeep required. Make sure that you check the battery life and charge the battery as necessary and clean the post and stanchions periodically.

Standard Cable Dropper Post Maintenance: Dropper posts with cables may require slightly more maintenance or trouble shooting if issues arise.

Adjust Your Barrel Adjuster: If the remote is not functioning properly and you are having issues dropping the seat post then you may need to adjust the cable tension with the barrel adjuster.

Change Cable and Housing: If the barrel adjuster doesn’t fix your issue then it may be time to replace your cable and housing all together.

Check the Air: If you have a dropper post that is pressurized by air (wireless or cabled dropper posts) and the post is having trouble returning back up then you may need to add air. 

Cons of Having an MTB Dropper Post

Weight: The biggest con of a mountain bike dropper post is the additional weight. Depending on what dropper post you purchase, it might add about a pound to your bike. Unless you are a World Class cross country mountain bike racer, a pound will probably be completely negligible to your riding experience. It’s much better to feel confident and ride with good form than to count the grams on your bike.

Complexity: Any time you add new things to your bike, there are more pieces that can break or cause issues. While dropper posts are generally fairly easy in terms of upkeep and generally quite reliable, it is still possible for them to break or get stuck. 

Cost: A dropper post will be more expensive than a standard seat post. Dropper posts might range in cost from $100-$800. The range in cost will usually account for reliability, durability, cables or wireless, and weight.

Longevity: Dropper posts don’t last forever. You will need to upgrade eventually. If the saddle starts to have some side to side play, if the post starts to sag by a couple of millimeters, or if it simply becomes less reliable or responsive, it may be time for a new dropper post. The good news is, by the time your dropper post wears out, there will likely be something newer and fancier on the market.

Drop Your Post and Drop Into the Trails:

Before you pass judgement on dropper posts, I highly recommend trying one out. Rent a bike with a dropper post, or simply lower your own saddle on your favorite descent. It may take a couple rides to get used to it, but next thing you’ll know you’ll be wondering how you ever rode without one.