Mountain Bike Reviews Forum banner
1 - 18 of 18 Posts

·
Premium Member
Joined
·
107 Posts
Discussion Starter · #1 ·
I tried lowering my dropper post flush with the end of the seat tube. When I lowered it, and activated the post to raise the seat, the seat would not stay up.

I raised the dropper post to its previous position: an inch above the end of the seat tube and it operated normally.

Would a shorter dropper post allow me to keep the dropper post flush with the end of the seat tube.

I’d appreciate any insights from the knowledgeable folks on this forum.
 

·
EAT MORE GRIME
(ノಠ益ಠ)ノ彡┻━┻
Joined
·
8,331 Posts
it can go as far in as you want as long as nothing inside the tube interferes with post activation

not knowing what bike make/model/size nor post, the above is mostly true
 

·
Registered
Joined
·
415 Posts
on my previous bike, SC5010V2, My bike yoke revive 150mm would be inserted all the way in seat tube and when raised would be ideal height for pedaling. Essentially it was perfect for climbing and slammed for descending. no issues.
On my current bike, SC5010v4, using the same dropper post i transferred over, seat tube shorter so dropper post can only be inserted so far before it interferes. For ideal climb height, it sticks out about 2 inches past the collar. when i am descending there is still same distance between my seat and my butt as before.
I think it all depends on the bike and the post.
 

·
Registered
Joined
·
56 Posts
There are a couple of obvious issues and one not so obvious one in using a seat post that rides right on top of the clamp to be at the right height. Obvious ones are that the inserted part of the post can't be too long for the highest obstruction in the seat tube; also, the internal cable/hose routing needs to be above the routing hole in the seat tube (and even a little more cable-actuated to keep from having a weird bend or angle that messes up the cable action.) The extra issue I ran into is that the top of the inserted part of the seat post is also the bottom of a bunch of seals, spacers and bushings. When you clamp around that section it can make everything start binding up, while 1cm down from there is fine to clamp on.
 

·
Premium Member
Joined
·
107 Posts
Discussion Starter · #9 ·
Thank you all. This is what I suspected. The existing dropper post is probably as long as the seat tube so pushing it down any further results in an issue with the operation. A shorter post should provide enough clearance to allow me to pit it flush with the seat tube.

I think PNW has a nice reasonably priced carbon fiber one. Might as well upgrade it if I’m changing out the part
 

·
Registered
Joined
·
2,175 Posts
Check out the OneUp V2 post. It has one of the shortest "insertion lengths" and is a good post and is affordable. They have charts for each size that will give you the insert length dimensions (as all posts do). Depending on the post, when you insert it deeper...you should also pull the housing (from the head tube area) taught...but not tight. Sometimes slack down in there can interfere with the actuation on some posts.

Thank you all. This is what I suspected. The existing dropper post is probably as long as the seat tube so pushing it down any further results in an issue with the operation. A shorter post should provide enough clearance to allow me to pit it flush with the seat tube.

I think PNW has a nice reasonably priced carbon fiber one. Might as well upgrade it if I'm changing out the part
 

·
Registered
Joined
·
505 Posts
I'm having a problem with a very long dropper post (210mm). Looking at the frame, it could go a little longer, but I suspect the tight corner of the cable housing is snagging the cable. Have played a little with the housing, and seems to improve (cable housing is external, and enters the frame at the bottom of the seat tube). Next step will be to use a flexible cable noodle for that specific corner.
 

·
since 4/10/2009
Joined
·
37,120 Posts
you need to do a lot of measuring to verify your frame's dimensions and your needs. you need to know exactly where any obstructions are inside the seat tube and what they are. Not only can obstructions affect insertion, but come can be an issue with some actuators. And also any time you make adjustments, make sure that the cable/housing isn't pulling/binding because that will interfere with actuation. AND make sure you don't overtighten the seatpost collar, as that will ALSO interfere with post function.
 

·
Registered
Joined
·
2,175 Posts
I've run posts through nearly impossible runs around the BB shell on a tiny 20" kids bike. The housing couldn't even move AT ALL without removing the entire BB...and it all worked fine. It worked with a KS Lev Integra because the cable could still slide on lever pull, and actuate the post. NOW...there are some posts that use the HOUSING to actuate the post. The BikeYoke Devine was like this and sucked for tight spaces (love BikeYoke tho). Those require the housing to move easily.

Now OneUp v2 210 posts used to have two actuators. The longer green barrel looking one is the old school one that depends on the housing to move. The newer 2.1 actuator used a tiny lever actuator that the cable itself actuates and is MUCH better and doesn't require the housing to move. If you have the old school actuator (and a OneUp v2 post), replace it with the 2.1 actuator. Its way smoother and doesn't use the silly housing to do the job (bad design imo).

Maybe this isn't your issue at all, but worth looking into. I've done a lot of droppers in tight, impossible spaces and they worked fine with some wrangling and a proper actuator.

I'm having a problem with a very long dropper post (210mm). Looking at the frame, it could go a little longer, but I suspect the tight corner of the cable housing is snagging the cable. Have played a little with the housing, and seems to improve (cable housing is external, and enters the frame at the bottom of the seat tube). Next step will be to use a flexible cable noodle for that specific corner.
 

·
Registered
Joined
·
505 Posts
I've run posts through nearly impossible runs around the BB shell on a tiny 20" kids bike. The housing couldn't even move AT ALL without removing the entire BB...and it all worked fine. It worked with a KS Lev Integra because the cable could still slide on lever pull, and actuate the post. NOW...there are some posts that use the HOUSING to actuate the post. The BikeYoke Devine was like this and sucked for tight spaces (love BikeYoke tho). Those require the housing to move easily.

Now OneUp v2 210 posts used to have two actuators. The longer green barrel looking one is the old school one that depends on the housing to move. The newer 2.1 actuator used a tiny lever actuator that the cable itself actuates and is MUCH better and doesn't require the housing to move. If you have the old school actuator (and a OneUp v2 post), replace it with the 2.1 actuator. Its way smoother and doesn't use the silly housing to do the job (bad design imo).

Maybe this isn't your issue at all, but worth looking into. I've done a lot of droppers in tight, impossible spaces and they worked fine with some wrangling and a proper actuator.
I was all happy that I'd solve my problem, searched for the V 2.1, that ends up being the exact one that I have. So either I'll need to reposition the actuator to a point where actuation is better or I'll have to use the noodle.

Sent from my SM-G975U1 using Tapatalk
 

·
Registered
Joined
·
505 Posts
I've run posts through nearly impossible runs around the BB shell on a tiny 20" kids bike. The housing couldn't even move AT ALL without removing the entire BB...and it all worked fine. It worked with a KS Lev Integra because the cable could still slide on lever pull, and actuate the post. NOW...there are some posts that use the HOUSING to actuate the post. The BikeYoke Devine was like this and sucked for tight spaces (love BikeYoke tho). Those require the housing to move easily.

Now OneUp v2 210 posts used to have two actuators. The longer green barrel looking one is the old school one that depends on the housing to move. The newer 2.1 actuator used a tiny lever actuator that the cable itself actuates and is MUCH better and doesn't require the housing to move. If you have the old school actuator (and a OneUp v2 post), replace it with the 2.1 actuator. Its way smoother and doesn't use the silly housing to do the job (bad design imo).

Maybe this isn't your issue at all, but worth looking into. I've done a lot of droppers in tight, impossible spaces and they worked fine with some wrangling and a proper actuator.
Turned out this was a good advice, although I already have the V 2.1 actuator. The actuator was tight on the bottom of the dropper, and I released it and rotated to a better angle. It was close to the front of the seat tube, now it's close to the rear. I also bent the housing the most I could, but it was not enough for me to slam the dropper all the way. Greased the cable (some will say I shouldn't but I don't care). At least the actuation is now smooth and fast.
 

·
Registered
Joined
·
2,175 Posts
Nice! Why not grease the cable? I've done that, wondering if that was a bad thing.

Turned out this was a good advice, although I already have the V 2.1 actuator. The actuator was tight on the bottom of the dropper, and I released it and rotated to a better angle. It was close to the front of the seat tube, now it's close to the rear. I also bent the housing the most I could, but it was not enough for me to slam the dropper all the way. Greased the cable (some will say I shouldn't but I don't care). At least the actuation is now smooth and fast.
 
1 - 18 of 18 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top