Mountain Bike Reviews Forum banner
Cancel
Create thread New Forums

What is a dropper post with the shortest base?

1 reading
Jump to Latest
21 - 30 of 30 Posts
#21 ·
shredjesse said:
I think approaching the math is incorrect. Here's the math I did, that worked for us and gave us results that matched our measured needs.
Click to expand...
I'm stoked you got a solution that worked for you.

I'm only chiming in because I think looking at the insertion in a vacuum is a common mistake. IMHO the dimensions that matter in 99% of cases are extended stack B from our chart (Collar to rail) and either Length A or E depending on whether your insertion is restricted by the actuator or the post.

For simplicity I'll only consider our 120mm post when shimmed to 100mm and assume that you are only restricted by the post (not the actuator).

Proper saddle height for pedaling is a constant. Your photos show the Brand-X post fully inserted. That means that your proper saddle height must be 155mm (the collar to rail distance of the Brand-X post). The collar to rail distance of the OneUp V2 100mm post is 133mm. That means that to achieve your proper saddle height the OneUp V2 would be 22mm higher than fully slammed. Yes our lower tube is longer (192mm) but only 170mm of it needs to be inserted into the frame to achieve the proper saddle height (versus 161.5mm of the Brand-X). Maybe that extra 8.5mm of required insertion is a deal breaker, I'm just trying to illustrate that the difference isn't the 32mm you outlined above.

In addition IF the actuator is an issue The OneUp V2 100mm post would be inserted 10mm less than the Brand-X 85mm post.

I hope this helps the community.

Jon @ OneUp.
 
#22 ·
This is precisely what the issue is for some short people. While the pedal height is constant, the fully slammed seat and still not being able to touch the ground is the concern.

So in your diagram, the F measurement is unable to be fully inserted into the frame. For example on my wife's Trance, there seems to be only 150mm of room for a post to be inserted before running into the suspension/bend in the frame. What is needed in her particular case is a dropper with ~150mm max insertion to set the seat lower when dropped, but still 100-120mm of travel for proper pedaling. I haven't found the solution for this exactly, but am open to suggestions...?
 
#23 ·
That's roughly where my fiance was at. 150mm of insert was the most we could get, she needed 120mm of rise or so from the top of the seat tube. With the collar adding 28mm, and the rise of the seat at 85mm, we're pretty much right in the vicinity for ourselves, and it sounds like just what you need.
 
#24 ·
I’m in the same boat looking for short seat post when collapse. Initially shredjesse post make sense but then I selves into it further and realized the important thing is not the insertion rather the total length while collapse. In this case the one up is actually shorter when collapse. Even though it has 120mm travel compared to brand x 85mm travel.

so here I am still looking for solution for short people. If anyone realize there is a market for it, my wife would be really happy.
 
#25 ·
I stumbled across this post after searching for a replacement dropper for my Specialized stumpy. I'm short with a small frame and am getting the same problem with my dropper bottoming out before it hits the collar. It seems as though I only have about 6 1/2 inches of max insertion length yet most droppers are around 8 in before any linkage.
Right now in my search, the best dropper I've found is the Brand-X Ascend II Dropper Seatpost which has a maximum insert of 128 mm...however this is an external dropper, so not much luck finding something internal yet.
 
#26 ·
Currently OneUp droppers are the ones with the lowest stack height, followed close by BikeYoke droppers. Regarding insertion length for the same travel length, if I recall correctly, they are both around the same. But they have different travel length, which will give you the option to get a post to best suit your needs.
 
#30 ·
Fast forward to 2022, we now have OneUp V2 90mm, with insertion length 167-15 mm= 152mm, which is about 6" of insertion, however, 90mm is a bit low of an extension. About 3.5", I can ride a bit better to 4", which is 100mm. However, there does not seem to have a dropper post with this specs; a 152~mm insertion, with a 100mm dropper height. I guess 90mm will do but OneUp V2 is so out of stock now for a few months. Anyone knows other brands that are closed to this 100mm? I've researched KS-LEV, 155 mm insertion, but 80mm dropper height, a bit low. KS Rage-i has rather good insertion length, 161mm but 75mm, I think both are about the same, Rage-i will always sticks out a bit plus the collar and then extend < 3". Where the LEV insertion is 3mm sticking out, but only 80mm ~ 3". So OneUp V2 90mm + collar might be just right.
 
21 - 30 of 30 Posts
About this Discussion
29 Replies
16 Participants
Last post:
samuraisd
Mountain Bike Reviews Forum
posts
16M
members
534K
Since
1990
A forum community dedicated to Mountain Bike owners and enthusiasts. Come join the discussion about bike parts, components, deals, performance, modifications, classifieds, trails, troubleshooting, maintenance, and more!
Full Forum Listing
Explore Our Forums
General Discussion Downhill - Freeride California - Norcal Shocks and Suspension Passion