This is the first of a series of four Suspension Tech articles that will look at one of the most neglected suspension elements on the bike – the dropper seatpost. Droppers are popping up on more & more bikes, with gravel and road versions becoming a real option – they’re not just for mountain bikes anymore. And that means a lot of bikes could get droppers. So if your bike didn’t already come with a dropper seatpost installed or if you just want to upgrade your current post, there are plenty of questions that need answering, starting with…

How much travel do you need?

Nowadays, there are options ranging from less than 60mm to 200mm of travel or more. Which could make one wonder, “How much dropper seatpost travel do I need?” From road to gravel to ‘cross, XC, AM, enduro, and beyond there’s a wide range of riders and riding styles to look at. We talked with a few dropper industry engineers to get their thoughts on the matter.

While rider preference & riding style are the first stop in determining the correct travel, Rick Taylor, Director of Operations at KS Suspension, reminds us that as droppers show up on a wider range of bikes beyond trail riding “weight is a factor for XC and CX racers, so many times travel is shorter for those applications.”

How should cyclists determine how much travel is correct for them?

KS-Zeta-road-gravel-cyclocross-bike-dropper-seatpost01

A lot of this comes down to why you want a dropper post in the first place. Do you want a really high saddle position for an optimal climbing position? But just need to drop the saddle a bit for sketchy descents, like a loose gravel road? If so, a super short travel <80mm post is probably appropriate.

Are you looking to drop the saddle to transition from a regular pedaling position to one where you can more easily shift your weight rearward for better control on technical descents? The somewhere-in-the-middle 80-150mm travel posts are probably your best bet.

Or are looking to spend a lot of time with your bike airing out over jumps, or dropping into super technical terrain where you just want the saddle completely out of the way? Then longer travel >150mm is probably your bag.

Of course weight is a factor, like Taylor says. So even though XC courses are getting more aggressive, weight conscious racers (like Gunn-Rita Dahle Flesjå & her purple hardtail there) opt for the shorter travel options. How much weight do you save going short? The KS LEV Integra 30.9 post weighs in at 410g with 80mm travel, and 545g with 175mm travel. That’s a 135g (0.29lb) difference from their shortest to longest options in that same model alone.

Stefan Sack, Founder & Lead Engineer of BikeYoke reminds us that “most people tend to think: Bigger is Better” but then can tend to not use the full drop very often. Like us, Sack keeps his post in the middle of its travel a lot for fast & flowy trails where he can “use the inside of [his] thighs and the saddle to keep the bike under control. Especially in fast steep turns you can benefit from the extra support of your legs on the saddle, stabilizing the bike underneath you.”

That also brings up the topic of travel depending on saddle shape. If you ride a saddle that already makes it easy to get your butt back to better distribute weight on super steep trails, then you might need a bit less travel than with a saddle that is harder to get behind.

Over at 9point8, Co-founder & Design Engineer Jack Pittens tells us they generally recommend “as much travel as will fit on your bike”, with most riders over time “tweak[ing] their riding style to take advantage of the full benefits of the longest post that will fit their bike”. But some do want less, preferring options where you can comfortably pedal from any position, even fully dropped, and that usually amounts to “around the 100mm travel range”.

At Bikerumor we’ve certainly seen a learning curve with most dropper posts, where we’ve needed to get a feel for the unique operation of the remote from brand-to-brand. And then once you get that down, figuring out how to use the remote to put the saddle where it feels most comfortable, both with infinitely adjustable droppers and those with preset drop points. Some companies like 9point8 make it easy to dial in exactly what you want, offering spacers that let riders reduce travel to customize their post to stop at the exact spot they want. And BikeYoke says they’ve done the same thing for sponsored riders looking to reduce post travel to their sweet spot.

Should dropper travel choice be discipline specific?

It doesn’t have to be, but often there is a correlation, both due to the limitation of the amount of seatpost that’ll fit, and the amount of travel needed for different styles of riding. In a general sense, the steeper and more technical the terrain being ridden, the more a longer dropper is beneficial. That’s why trail bikes were the first to fully adopt dropper seatposts.

Regarding frame fitment limitations, you aren’t likely to have room for a 180mm travel dropper in a road bike if that bike is anywhere close to fitting you in the first place. But, longer dropper travel has influenced bike design in disciplines like all-mountain & enduro, where new frames are getting more compact designs so the more recent crop of super long posts can be used to get the saddle even lower. The trick is making sure there’s enough seat tube to handle the post when fully compressed. We’ll drop (pun totally intended) deeper into post-in-bike fit in another installment.

At the other end of the spectrum, markets just now joining the dropper party, like road, gravel, bikepacking, and to some extent even cross-country are being driven by a desire to add on as few grams as possible. When weight is a concern, limiting travel is the easiest way to shed grams.

The way Pittens puts it though, “as riders gain experience with droppers, the negatives of extra travel go away, with the exception of the small weight penalty of a longer stroke… So we tend to think it is more the type of trails you ride, and how you use the dropper, than discipline.”

Should post travel depend on bike suspension travel? Or even tire size?

Again, it doesn’t need to, but for sure there tends to be correlation. This goes back to matching travel with the types of terrain you ride. KS notes that frame size, rather than frame travel, tends to dictate how much travel is possible with dropper posts.

Stefan Sack of BikeYoke reiterates though, that this is actually an important issue to address, due to the trend of combining long suspension travel with very compact chainstays. “In combination with [even] a moderately steep seat tube angle, this can lead to critical interference, [where] a fully slammed post would cause the tire to hit the saddle at bottom out.” So if you are looking at putting a super long dropper on a long travel bike, first make sure the tire would still clear a slammed saddle when the rear shock is fully compressed (Tip: Just let the air out of your shock…not as easy with coil spring set ups, sorry). And then remember that if it’s close, putting a larger tire on there later means you need to re-check clearance.

Should post travel be a function of how tall the rider is?

Simply put, Yes. If you are looking to drop the saddle to a position that is still comfortable to pedal in, the rider with shorter legs is going to need less drop, and a long-legged rider more. Even if you are looking primarily for maneuverability, smaller riders will get proportionally equal benefits from less post travel. While at the same time, a taller rider will benefit more from the long dropper allowing them to get their higher center of gravity further back and down to comparable levels.

Coincidentally, smaller frame sizes typically also mean the longer travel dropper posts won’t fit anyway, so rider height, frame size and available dropper travel tend to run along a similar curve.

 

When it comes down to it, answering the question of “how much dropper seatpost travel should I get?” starts with being honest with yourself about how much travel you really need based on your terrain, riding style, and type of bike. The topics discussed here give you food for thought. From here, your choice might come down to how much you can fit in your bike. That’s a whole separate topic; one we’ll get into next week!


The fun never ends. Stay tuned for a new post each week that explores one small suspension tech, tuning or product topic. Check out past posts here. Got a question you want answered? Email us. Want your brand or product featured? We can do that, too.

37 COMMENTS

    • Your seatpost diameter is 31.6mm. As for drop amount, measure the height of your seat in the optimal pedaling position (seat clamp to saddle rails) and look up collar-to-rail heights for dropper posts. For example, a RockShox Reverb with 125mm of drop has a collar-to-rail height (i.e. minimum height) of ~190mm – the seat clamp and seal head take up about 65mm combined, which has to be added to the drop amount. For other sizes of the same post, you can just add/subtract the change in drop amount – i.e. a 100mm Reverb has a minimum height of ~165mm while a 150mm Reverb has a minimum height of ~215mm. Different posts have different collar-to-rail heights though, so if you’re right on the cusp with one, another might fit. The posts with the shortest minimum heights for their drop amount (that I’m aware of) are the Crank Bros Highline and Fox Transfer.

  1. I loved my 125mm dropper post, and thought, “why would I ever need more?” Then got a new bike with a 150mm post and it took me all of 1 ride to realize how much better the 150mm of drop is. I’m sure it’s individual needs, but I wonder what beyond 150mm is like? Is moar drop like moar shims?

    • Never. Enough. Shimz.
      More seriously I expect 170mm is about the practical limit, even with me riding an XL bike dropping more than that seems like it will end with backside meeting tyre in exciting situations. The 125mm drop post I have now isn’t quite enough, the saddle is still above the bars fully dropped, but 170mm would put it about where the slammed position would be with a standard post.

        • Watch any WC downhiller. Knees (and elbows) are out; bike and body move independently of each other thru awkward terrain. I have never really understood this “thigh-steer” nor have I seen much evidence of it in pro-level riding.

          • Who cares what the pros do? I’m not racing. I have a 3 position Fox dropper post and I use the intermediate position all the time for that reason – I like the extra control I can exert through the saddle. For jumping or more extreme downhill I would slam it, but for XC riding it’s totally unnecessary and undesirable.

              • Through straight line technical sections – no, they dont ‘grip ‘ the saddle. Off camber rises, drops, tight high lines, cross fall line airs etc. ? There’s constant contact with knee and thigh, sometimes just locating the bike, sometimes part of the push/steer. Look at photos from any of the great DH runs (Danny Hart in Champery, Aaron Gwin chainless, etc.) and there’s plenty of photo evidence of thigh to saddle.

                Your image of pro riders arms and legs akimbo like billboard apes on circus tricycles hardly matches correct form…

          • Yes, Eric E.: Right, watch any of the DH videos. Ýou will see, that there are a lot of situations, where they use their legs to help steer the bike.
            Look at those DH bikes:
            https://www.mtb-news.de/news/2016/06/29/pro-bike-checks-wir-nehmen-die-raeder-von-den-schnellsten-worldcup-fahrern-unter-die-lupe/
            See any of them riding with the post slammed completely? If it was better to have the post slammed completely, why is no one of them doing it? Some of them are extremely high. Why? Because the do use the saddle to direct the bike with their legs. Talk to them and tell them what they´re dowing wrong.
            Or just simply watch and feel yourself going down on your next trail with compressing turns, how much you do use your thighs yourself.
            Jared Graves has been riding our 160mm REVIVE for over a year now, and he was coming from a 150mm Reverb. After a few races he asked us, if it was possible to reduce the drop to 150 or 140, because 160mm was just too much for him. Prove him wrong!
            I´m not saying, this applies for everyone, but definitely the fastest riders on earth figured out, that there is a position too low.

        • why: because it is unstable. you want to be stable.
          motorcross bikes are MUCH WIDER than mountain bikes tyler…

          now if you’re doing a whip or something, you will indeed push the bike with your legs.. like one of your legs, of course. but not for general descending…

    • This is great advice. You lean your saddle against ONE leg often in situations like off-camber corners, “foot out flat out” turns, and quick direction changes to help control the angle of your bike to the ground. Try taking your saddle off your bike and ride downhill… it just doesn’t work, you lose a huge element of control. Who was the idiot who said knees out? I haven’t seen any bow-legged downhillers winning world cups. Now if your pinching your saddle with both legs, then yes, you are a goober; the only acceptable situation for this is if you’re doing a suicide-no-hander.

  2. i’m 5’11” and honestly 75mm is fine for me to get it out of the way and still be able to use it for control. where i live there isn’t anything super steep that requires a massive drop in seat height. also i often pedal with the saddle dropped to rest and work different muscles and i hate pedaling with my seat so low that my knees are higher than my hips at the top of the pedal stroke.

    • it depends on the frame, descending style, etc.
      im 5″11 and ive a bike with a 125mm dropper the other with 150mm. the 150mm feels almost too short, the 125 feel perfect.
      the frame is way different between the two bike though. also if i dont descend the freakiest steepest stuff i barely need to get the seat down on either bike. technically, i can drop behind the seat too without dropping it, its just really annoying and feels dangerous.

    • Well there is some flex in the seatpost, so that’s a couple of millimeters. Beyond that I can’t think of why I would make any part of the bike heavier, it’s pretty easy to get behind the saddle anyway. I suppose I could get lower if the saddle wouldn’t hit me in the chest, but realistically that’s not a position that I could control the bike from anyway.

      • I don’t use a dropper myself, but I can easily see why one would. Getting behind the saddle isn’t the only way in which the saddle gets in the way. Lowering your body or allowing the bike to travel straight up is also a big benefit. Can’t do either with a properly high saddle and no dropper.

      • It makes all the difference when riding, it almost sounds like you havent tried one. I held off using one for ages on my 140mm trail bike and after i switched my rides flowed better (not just descending). The benefit of getting lower outweighs geting behind the saddle in my opinion. Who gives a sh*t about an extra 400g when the whole bike is more stable.
        Each to their own, if you dont want one, dont get one, but they make such an improvement to my rides that i have to recommend you try one for a ride.

  3. I installed a dropper with 125mm of travel on my XC bike last year and I’ve foudn its wayyyyy too much. I almost never want to drop my saddle down that far, and when I do, I feel like it actually makes me slower. I like to steer with my thighs and I can’t do that with the saddle down so far! I’m actually thinking I’ll limit mine to 75-80mm!

  4. On my 120mm travel 29″ trail bike I liked my 125mm reverb, but I like my 160mm bikeyoke revive better in every way. I put it in the middle from time to time, but I also slam it just as often. Flow, steep, tech, smooth, I find reasons to go as low as possible.

  5. I tell you what I DONT want is a dropper thats connected to my suspension remote a la BMC. Pretty funny how we are in 2018 and they still think that locked suspension means dropper up and open suspension means dropper down. no in between, just an engineer at a desk deciding how you should ride. lame.

    ANYWAY, i think we can all agree that droppers are great, sometimes more sometimes less, but all amounts of travel are better than nothing!

  6. I would put as much dropper in your frame as it will allow. I have 150mm in my current bike, and only have about 15-20mm of adjustment left before my post would be bottomed out. I think most people would benefit from at least 125mm, but if you can get 150mm or more, I’d go for it. Frankly it’s been the single biggest advancement in the last decade. I no longer compromise between most advantageous seat height for pedaling and for trail riding, I can have my seat where it belongs for long pedaling bits, and then drop it in the technical sections.

  7. I was an early adopter with dropper posts and have ridden them on every mountain bike I’ve owned since ’05. As such, I can speak with some authority and experience on the matter. I remember thinking at the time that everyone will have these on their bikes, even though most people looked at me like I had two heads back then. People still look at me funny however likely for other reasons, but I digress. Regarding amount of dropper to choose, I feel like if you have it, you will use it. The ONLY place a shorter travel dropper would be of any use would be on a bike that is not going to be ridden aggressively (no jumping), eg a gravel/road/CX and maybe some XC bikes. Otherwise, I think it’s best to have as much as your legs and frame will allow. This makes sense not only for actual ergonomics and one’s ability to move around it, but dropper durability is improved by not landing on it with it extended even slightly when airing things out.

  8. I was a dropper skeptical until I bought a bike that came with one. Specialized Command post with -35 and -100 mm settings only. Still use the -35 most, so would stick with a short and light post.

  9. I have found the appropriate amount of drop is a function of rear wheel travel and actual seat angle. I personally want the saddle as low as possible without inducing saddle/tire rub on bottom-out. Having the saddle out of the way for fall-line steeps and moving the bike around in the air is essential, and my 150mm post doesn’t quite get there for me (5’10”, 450mm seat tube). 150mm drop is more than fine for riding trails, but as soon as I enter real DH terrain the post slides into the frame an extra 1-2cm.

  10. for now i dont see the bennefits of a dropper that justify the extra weight and complexity…that being said i tried a suspension fork but ended up riding it locked out all the time because i liked that better and put in my rigid fork again, so mayby i’m not the best reference for advice 😉

  11. Good article, but I object to calling a dropper post a suspension component Despite the fact that most droppers are made by brands that also make suspension components, suspension is something that dynamically reacts to ground forces, increasing traction, stability, and comfort. Suspension concepts like sag, sprung/unsprung weight, and critical damping don’t apply to seatposts.

  12. Hi,

    On a Scott Spark RC900 team, 2018. I’m 6″2 and am on the L frame, riding on pretty technical terrain and looking to go downhill a little faster 🙂

    I can’t seem to source anywhere what length dropper post I can install, although am clear I should be looking for 120mm-150mm of travel. Can anyone advise, please?

    Cheers.

COMMENT HERE: (For best results, log in through Wordpress or your social media account. Anonymous/fake email comments may be unapproved or deleted. ALL first-time commenter's posts are held for moderation. Check our Comment Policy for full details.)

This site uses Akismet to reduce spam. Learn how your comment data is processed.