Edited Date/Time
3/17/2025 8:00am
How long should my dropper be?
What's the seat post insertion depth on (insert bike)? If you know, add the deets below.
Are there apps for figuring out dropper length? (Vital member @Vincent P shared one he built - www.dropperchecker.com )
Every human is different and every bike is different, so how do we make sure our dropper posts are working toward the ulitmate riding experience?
Talk about it all here.
Even at over 6’3” tall I think super long droppers are overrated. 170 or even 150 is completely fine on the steepest features.
I’m 5’8” and have long legs and a short torso. A medium size bike fits me perfect, but I need a pretty high seat height. I have a 200mm dropper on my Jekyll, which is still not fully inserted into the frame, but drops low enough for my liking. My hardtail, on the other hand, has a 150mm dropper only because it’s at its max insertion depth. For me, I’ll take the max drop length possible for it to sit flush in the frame and give me the most clearance possible. There are plenty of times when I only drop it part way to hit a short technical section, where I’m seated just before and after the tech section. Best way to begin the search for a bike that doesn’t screw you over in this department is to measure your seat height at full extension. Then you’ll have to do some math on your overall dropper length (of your chosen dropper) and compare that to the max insertion depth of the frame you are looking at. Just my 2 cents.
150 as someone 6'3? that's insane.
I'm 5'9 and run as long as I can. I've 200 on my last three bikes and can't imagine riding any shorter.
Running 150mm on XL bikes ? This is complete madness, there's no way this is safe to ride on steep stuff.
I'm also 6'3'' and 200-210mm is the minimum to have proper freedom of movement on steeper trails.
170 (pictured) puts seat at my knee, perfect for control, XXL YT Capra MX. 150 works fine too and I never got hung up on it even on a 2017 Reign SX that had a pretty slack seat tube.
For anyone riding a 2024+ Rocky Mountain, there's a seat post fitment chart (sorry no app..I'm not good at computers) in the tech manuals that list all relevant information. It's based on the spec saddle height (45mm for a WTB Volt) and takes cranklenghts out of the equation since measurements start from center of BB. Pg.11
https://cdn.shopify.com/s/files/1/0449/1496/6691/files/MY24_altitude_v1.3-min_compressed.pdf?v=1716825135
The lack of an app or web-based database is poor for doing updates with new droppers, but at least the starting info is there. Were I still a PM at Rocky, one of my projects was to get some resources allocated to a web-based calculator like what Santa Cruz has.
j/k, of course.
I have really short legs proportionally so I feel like this guy a lot. KotH still pops up in my brain all the time. It's been 10 years since I've seen an episode and some of the jokes manifest themselves in my brain weekly.
I'm 180cm (5`11") my seat tube length is 415mm on my Nicolai G1. The max insertion length is ~315mm. I run a 200mm dropper but it sticks out 2cm so I would like to run a longer dropper. I tried a 240mm oneup V2 dropper but it is too long, 337mm to run it slammed.
If I could I would have an even shorter seat tube and run a 250mm or 260mm dropper post. I like to have the seat completely out of the way.
On my trail bike the absolute longest I could fit was a OneUp V2 at 190mm, it's completely bottomed out in the frame and gives the correct saddle height when fully extended. Previously I had a 170mm post and I felt that this limited the capability of the bike, probably because I was used to 200mm on my enduro bike. I never felt the need to go longer on the enduro bike, if I did I think it might make the dropper on the trail bike feel too short.
We used to ride no dropper and slam it into your stomach. It sucked. Every dropper I increased size on I liked more. 125, 150, 175, etc. I now have two bikes, one with 180, one 160. I added a Switchgrade to the lower one to compensate.
One thing that isn't discussed and maybe only a smaller frame issue is seat contact with tires. Although my Switchblade could run a 200mm, I couldn't as it would bottom out into the seat (even with a cutout). Something to consider on the smaller end of the spectrum.
I also have an aenomly switchgrade, and while that I can make it longer for effective drop, the same issue with seat / tire contact can happen. My 170m 27 wheeled bike with a 160mm saddle if pushed back will contact the tire.
Current BB to seat rail = 625mm. Ideal dropper = 170ish.
Personally I always used the oneup dropper calculator when considering a new bike.
https://www.oneupcomponents.com/pages/dropper-post-length-selector
Basically I took 625 - STH to give me the collar to seat rail calculation. Then the specs from the site. Maybe its within a MM or two off, but gets real close. While the calculator said I could run a oneup 210 on my switchblade, the seat would be ripped off in the first drop.
@Vincent P One more thought on the website if you really want to have a go at this, and it's something worth keeping in mind generally when dropper shopping: the more you shim a post, the less impressive the overall length for the amount of drop becomes. I haven't done the math in a while, but a OneUp 240 shimmed to 210 might fit fewer frames than another post that's 210 without any shimming. As far as the website/app, this would translate into a comparison function that would allow you put a few different options up against each other to see what fits.
Santa Cruz says the longest dropper that will fit my 2021 Hightower V2 is 150mm. Luckily I was barely able to make a 175 Transfer work. I really like the extra room.
Thanks @sspomer for the shoutout and for starting this thread. At least here the only thing that will get slammed are some dropper post. 😆
Thanks all for the feedback too, many improvements already including a model database for droppers
Hope this isn’t rubbing salt in a wound, but I have really loved that my both my 2022 and 2024 Elements (XLs.. one was metal, one carbon) would easily take a 240mm OneUp post. My saddle height is about 81cm from the BB and its not slammed down.
At 6’2” with not the greatest bike skills I’ve always wanted as much drop as I can get, and while 240 on an XCish bike might not make sense on paper, I have absolutely loved every minute of having almost double the suspension travel in a dropper. I looked hard at Epic EVO this past summer and didn’t pull the trigger for because I didn’t think I could fit a 240 post and that 180mm rotors were the biggest Spec cleared for the rear of the bike.
My take is definitely 'more is more'. At 5'8'' on a full 29" I need every last mm. I do love Transitions' frame design for having very low stand over which allows me to run max drop. On my V2 Sentinel I am running a 210 ONeUp V3 with about 15mm of the post still showing. To make this work I run 155mm cranks which get me ample clearance. The saddle just disappears underneath on the downs. Just picked up a different HP frame, and with the compromises in seat tube architecture I am going to try 150mm cranks to see if I can get 160-170mm of drop. In combination with a mullet set up I think I can get the set up where I like it.
This is wild. I'm 6 feet on the dot, and my new bike came with a 170 mm dropper. I rode it nine times before my 210 was delivered. The 170 functioned as it should - went up and down - but it was getting in the way of how I ride and maneuver a bike. A few years back I was on the "a dropper is just a dropper" side, but after upgrading to a post with more drop, I can never go back. It made a bike I had for 2 years feel like a completely new (and more capable) bike. I am now firmly in the maximize-drop-on-all-bikes group.
I forgot to add that fitting a 210 on my new bike was very close. I bought the lowest stack height saddle I could reasonably find to make it work and I will never regret that decision.
181cm tall and find a 150mm drop to be plenty. Even at 150mm I don't regularly drop it all the way. I scratch my head at how people find a need for 200+mm droppers.
It's not about what you need, it's about what you might need. Just like driving a truck for getting groceries.
The beauty (and frustrating) thing about cycling is there's so much variation in needs and expectations that there is no right or wrong, so it's best to cover all options and spec the most drop possible.
Your bike explains it all as the Capra has the longest seat tube out there that's why you're getting away with a smaller dropper.
This bike is often getting criticized for its very long seat tube that is getting in the way.
If the seat tube was 415 I would still only need a 150-175 length dropper. It’s clearly not in the way. It’s also roughly the same height as my last 3 dh bikes.
A question for the peanut gallery: when your saddle height is too low or too high, you grab a 4mm allen to loosen your seat clamp and adjust your seatpost up or down. How much do you adjust it by?
I'm a micro-fiddler, typically adjusting seat height by less than 5mm. And I notice it immediately. My body is incredibly creaky and tight and not flexible, so having my bike barely out of position when pedaling is really noticeable, annoying, and eventually becomes painful. For bike fit, I have a very small optimal setup window.
Why bring this up in a dropper thread? Because I've observed a lot of people who seem happy to run the tallest drop post they can, slam the collar of the post down to their seat clamp, and call it a day. There's no way that would work for me. I would almost certainly need to adjust it up or down 3-7mm to find my correct height, and not having room to adjust would break me. But lots of people are humming along happily with their post not quite right, either not noticing or not caring. Which camp are you in, and how much do you care about 5mm of adjustment?
WARNING: OLD PICTURE STILL RELEVANT SOMEHOW
I don't care about 5mm of adjustment, but hot damn my knees certainly seem to care and quickly too (under 5 minutes of improper saddle height and my knees bark). I'm in the same camp you're in... I've only had one bike where i could slam a 240mm seat post, shim it down by 20mm and have it be perfect. For all of the rest of my bikes, I'm using 210's and then adjusted to height with some post showing. 6'2" on mostly XL's with a 30.5" bb to top of saddle height. The only way that 30.5" dimension changes is with different crank length.
Getting old sucks (well not really, but some things do).
Usually my tweaks are like 2-5mm. Like you said, a tiny change can make it go from feeling terrible to just right.
I'd like to jump on the bandwagon of railing against spec'ing too short of dropper posts, especially on size medium bikes, and extra especially on top tier builds that include an AXS Reverb. I'm 5'8", 30" inseam and have been running 170+mm droppers for like 5+ years. 185 BikeYoke had about 35mm extra space. I've ridden a buddy's medium bike that had a 210mm OneUp and I had like 20mm of space left on that. Even my current 170mm AXS with it's hugely inefficient stack has about 30mm extra space. So when I look at buying a medium bike that includes a 150mm AXS, I think that I'm basically paying extra to have to take off that part and try to sell it at a huge loss. The worst dropper spec I've seen is Crestline putting a 150mm OneUp dropper on their size medium (RH2) frames... WTF. I don't think these produce managers realize that shit like that causes people who would otherwise spring for their top end build kits to take a pass.
I'll certainly play with post height in the 3-7 mm range till it feels right.
I'll also make an adjustment if I know it's going to be a long singletrack climb (1200+m of constant climbing). Might even adjust saddle tilt a wee bit.
Also for long extended Dh usually enduro racing I'll drop the post in the frame aprox 30-50mm. The new full height position is now at a spot that it's usable for "rest" pedaling on flats and if I get caught out on something a bit more technical than expected with it up it's not a full climb height and easier to manage. No need to fiddle with in between position while racing, it's up or it's down.
My latest bike shipped with a 180mm dropper. It's wildly perfect the slightest bit above slammed - a couple millimeters at most. I could run it slammed (and did for a bit) but eventually realized my knees could be a little more comfortable up just a little bit. The truth is it probably doesn't make any difference...but my brain felt it so my knees felt it so now I'm more happily riding at that height.
Going to 180mm from my other bike's "can't go any longer of a dropper because of a bend in the seat tube" 150mm dropper felt crazy. It shipped with a 125mm so the 150mm was an improvement...but somehow felt like way less of a change than the 180mm post feels. Brains are dumb.
I am picky as well. I feel the difference when wearing DH shoes with thick soles, I feel the difference when riding in padded shorts, I get annoyed if the post slides 1-2mm down in the frame, or if the saddle moves back... Frikkin knees and muscles have a memory of their own.
Another micro-adjuster. I'd adjust 3-5mm at a time. On my Madonna, I'll run wolftooth pedals and freerider pros for pedally rides. On a big shuttle/park days, I'll switch to Dagga's and Impacts. I notice the difference in pedal/sole thickness. Not like it makes any real difference, but it feels weird and too low. I'd raise the saddle a hair if I was going on a pedaling ride with that setup.
Sometimes I think people try to get the saddle as high as they can tolerate under the theory it helps their knees. But too high can cause you to slightly extend your lower back, and when you're old, tight, and rickety, that's not good either. (Giving people credit to notice when the saddle is so high they are rocking.) I feel like I've got it right when knees and back hurt moderately and equally . . .
Getting old has made me a religious knee pad wearer, even on XC-ish rides, which I think is good. Worst falls often happend on easier trails and such.
But my newfound resolve isn't about being safer. I've just realized that if I always wear knee pads, my knees warm up quicker and I'm less likely to tweak anything! 😂
We're happy you're using your newfound wisdom, Grandpa.
50 and knee surgery last June. I also have to have it juuuust right if I’m riding clip pedals. Flats I can get away with +/- 5mm without issue.
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