Dropper Post Insertion

T.3

Likes Dirt
I made an enquiry with a bike company regarding if a dropper post could be inserted all the way into a frame. By this I meant all the way to the collar leaving little if any of the lower half of the post exposed. In reply I was told "If a dropper is inserted too far it can stress the frame and cause damage"

I understand if the seat tube is interrupted or kinked you don't want any part of the post making contact with where the frame bends or with whatever is interrupting the seat tube. I also understand the concept that a post has a minimum insertion to protect the frame.

My question is does anyone know of a reason why (assuming the frame will allow it and will not contact anything internally) a dropper post can not be fully inserted into a frame?

I had a quick google and doesn't seem to be a problem but am curious to hear peoples experiences.
 

rangersac

Medically diagnosed OMS
Logically that seems completely arse about. The less post in the frame, the more stress as the post acts as a fulcrum on the seat tube.
 

creaky

XMAS Plumper
The frame manufacturer should be able to advise the maximum recommended seatpost insertion length for each frame/size.
 

T.3

Likes Dirt
I did quote the model and frame size that I was looking at and that in part was the response along with it was "unlikely" the post would go all the way in.

The question more is if the post can go all the way in is there any reason it shouldn't?
 
Last edited:

teK--

Eats Squid
Bottom out all you want as long as bottom of post /cable doesn't interfere with part of the frame.
 

Tim_the_Clyde

Likes Dirt
Run plenty of droppers with collar close to clamp - ie within 10mm.

Best option as I like to maximize the dropper travel.

Can’t see why it could be a problem to sleeve a post over a longer distance. In steel work for construction longer sleeve joints are stronger. The post is only clamped at the top of the sleeve but you think the longer overlap would limit deflection.


Sent from my iPhone using Tapatalk
 

Nerf Herder

Wheel size expert
What frame?
If the tubes are perfectly uniform in inner diameter and uninterrupted by welds, kinks, or other tube manipulation then it’s just a T.I.T ... to partially steal from Tranny
 

Flow-Rider

Burner
I run 3 droppers slammed into the seat tube, no problems here. There must be something odd with the frame if the manufacture has told you that.
 

Nambra

Definitely should have gone to specsavers
Only speculating, but perhaps the response OP got from the bike company is related to the additional rigidity a deeply inserted dropper would add to the seat tube.

The frame is likely to have been designed as a dynamic structure, with flex and stresses under load modelled by computer. Perhaps by making the seat tube stiffer with a deeply inserted post, the frame cannot flex under load as it was designed to, and stresses are transferred and/or concentrated where they shouldn't be, with the potential to damage the frame.

This would be poor design though, as you'd think that the frame designer would reasonably anticipate use of slammed seat posts, droppers or rigid. IIRC, the frame on a bike I used to have had only the top 100mm or so of seat tube at the correct diameter for the post, with the seat tube flared wider below that - maybe to allow flex regardless of depth of insertion.

Just speculation - could be pferdescheiße too.
 

T.3

Likes Dirt
It's a Trek Slash.

I've done a bit more image searching and there are a few people running their droppers fully in, although not sure what size frames are depicted.

As a very unfortunate coincidence a mate had a big crash while riding yesterday and he runs his dropper all the way in. I picked his bike up for him last night and the seat has been impacted so hard that it has skewed the saddle rails to one side by about 45 degrees. No damage to seat tube.

I'll send an email clarifying my question and see what the reply is.
 

T.3

Likes Dirt
I guess that's possible Nambra, will try and get some further detail and report back.
 

T.3

Likes Dirt
I've sent a reply email asking for clarification as to whether the issue is an obstruction in the seat tube or some other issue as touched on by Nambra
 

T.3

Likes Dirt
Get a hold of the cheapest rigid seatpole you can and test it for depth. Then buy dropper based on that?
Fair call but I would ideally like to know if its rideable with the stock dropper before I slap down money.
 

Ultra Lord

Hurts. Requires Money. And is nerdy.
They just covered their arse, if your bike breaks they’re not liable.

Dicks.

If it doesn’t hit anything, slam it. No need to hit up a company and get some bullshit reply that ensures they have zero responsibility.
 

Duane

Likes Bikes and Dirt
I've found setting up a few bikes that some brands of post can have interference from the cable activation causing the post to not operate correctly (won't stay down typically), just something to be aware of when slamming the post, the frame might allow it but the post design might need a bit more room.
 
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