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Dropper posts on road bikes

2769 Views 39 Replies 12 Participants Last post by duriel, 2 mo ago

ogre

Discussion Starter · 3 mo ago

Anybody running a dropper post on their road bike? The pros are doing it. This year's Milan-San Remo. They show the trigger and post at 0:45 but no other mention. I wonder if it's an useful on some of the swtichback descents, or maybe it's more aero since the super-tuck is outlawed. Also, be sure to watch at 1:40 for a few seconds of Allephillpe passing through the team cars and at 2:35 when the peleton squeezes thru a constricting turn.

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One Wheel

· #21 · 2 mo ago

They're nearly universal on mountain bikes. There's typically a lever on the handlebar that releases a catch, so that when you sit on the seat with the lever pressed it drops the seat to a lower position. When the lever is pressed again without weight on the seat the spring or compressed air that was compressed when the seat was pushed down returns the seat to its original position.

tlg

· #22 · 2 mo ago

2

Fredrico said:
Wow, for sure I"m now hopelessly behind the times.

So how does the rider manipulate the thing? How does he lower the saddle to tuck through the corners and descend mountains? Most riders would want seat height to be the same no matter what. There's nothing worse than a slipping seat post. What's the deal?

Push a button it goes down. Push a button it goes up.
Max seat height is always identical.

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duriel

· #23 · 2 mo ago

That dumby on the road bike with a dropper post is running a 1X ? He's not going up a mtn, why does he need a dropper?
I think even Contrador ran a 2X, just say'in!

One Wheel

· #24 · 2 mo ago

duriel said:
That dumby on the road bike with a dropper post is running a 1X ? He's not going up a mtn, why does he need a dropper?
I think even Contrador ran a 2X, just say'in!

The dropper is for going down the mountain.

tlg

· #25 · 2 mo ago

duriel said:
That dumby on the road bike with a dropper post is running a 1X ? He's not going up a mtn, why does he need a dropper?

Derp. Not all bikes are road bikes. And droppers have multiple uses.

www.trainerroad.com

How to Install a Dropper Post on a Cyclocross Bike [VIDEO]

This tutorial will teach you how to install a dropper post on your cyclocross bike.

www.trainerroad.com

Dropping your saddle away from your body allows you to navigate tricky terrain, including barriers, with greater ease.

Reactions: 1

craiger_ny

· #26 · 2 mo ago

One Wheel said:
The dropper is for going down the mountain.

How did you not anticipate what is coming next?

Fredrico

· #27 · 2 mo ago

tlg said:
Push a button it goes down. Push a button it goes up.
Max seat height is always identical.

Trick! Can't wait to get one! Sliding back off the saddle and going into a full tuck never worked that great on a nice descent. This is obviously much better!

How many times do you accidentally drop the saddle when you mean to shift?

duriel

· #28 · 2 mo ago (Edited)

ahhh, bring your x1 and we'll see how you get to the top of the mtn first!!! Your GF going to drive you to the top? uh huh???
And the bike in the gif isn't a mountain bike! HELLO! ... ok, well it may be a cyclecross, but really have you ever rode one?
And ... that title isn't in the gif on my screen so go find some mud and jump in it!

.. I rode up the mtn with my buddy on a cyclecross race bike, coming down he couldn't keep up with my Gravel Santa Cruz, cause .... suspension! ... pretty sure he didn't have a dropper, but it would not have helped him!

tlg

· #29 · 2 mo ago

duriel said:
ahhh, bring your x1 and we'll see how you get to the top of the mtn first!!! Your GF going to drive you to the top? uh huh???
And the bike in the gif isn't a mountain bike! HELLO!

HELLO!!!!

Font Slope Rectangle Terrestrial plant Darkness

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regan40c

· #30 · 2 mo ago

My MTB came with a dropper and I ended up taking it off. I made myself use it a few times but didn't really care for it. Maybe if I would have kept at it, it would have grown on me, dunno. I guess I'm just old and set in my ways.

duriel

· #31 · 2 mo ago

tlg said:
Non round pistons are quite common.
Seen them. Used them. Designed them.

Ok I got some time to get back to this…. I’ll have to say your post was the KING of DERPS!
First off the title of this thread is "Dropper posts on road bikes"!
Non Rotating Air Cylinders:
First one: It runs on compressed air, you used them, I guess you forgot that it requires 250psi compressed air to operate. Where are you going to install this on the bike??? Or did U use CO2 cartridges??? Hmmm?
One of those with a 5” stroke is listed as .28lbs, for some reason I don’t believe that. But anyway the air compressor is going to be way more, and don’t forget the power supply, either a big battery or a loooong entension cord.
It has a ROUND cylinder of 9/16”diameter, so … round. It doesn’t list the outside dia, but looks something around 1", so maybe it might fit although fastening isn’t really too clear.

Second one: Couldn’t really find that exact one, but this is a review of a similar one available.
It looks like someone distorted the body, cause I couldn’t find any that didn’t have a ….. round bore. Exactly how is this going to fit in the seat tube? I think the same comments on item one apply here, sorry.

Please post specs on all the dropper posts you designed using ‘non rotating round pistons’, post a picture of your bike with one, what were the design perimeters? ha ha ha!!!

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tlg

· #32 · 2 mo ago (Edited)

duriel said:
Non Rotating Air Cylinders:
First one: It runs on compressed air, you used them, I guess you forgot that it requires 250psi compressed air to operate.

Derpity derp
Air cylinders operate on ANY pressure. Depending on the force required.

Guess what.. plug up the port on a cylinder then sit on it. And it compresses the air inside 😲
Get off...and it extends. 😲😲
A single acting air cylinder

First off the title of this thread is "Dropper posts on road bikes"!

So. We were also talking about MTB droppers.
Fred was confused what they were and I provided examples of their operations. It's irrelevant to the type of bike.

YOU were the one who said "And the bike in the gif isn't a mountain bike!"
Well nobody claimed it was.

These single acting cylinders don't use air compressors either 😲 😲 😲

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duriel

· #33 · 2 mo ago

.... so you used those door hold opens as a dropper post? ...that's what the thread is about.
By definition a dropper post has to go up and down controlled via a lever, not some BS tail gate support.

... sorry, I thought you were responding to my comment as 'fred's' posts are somewhere where I cannot look. Kinda like the beneguserits!

craiger_ny

· #34 · 2 mo ago

duriel said:
Ok I got some time to get back to this…. I’ll have to say your post was the KING of DERPS!
First off the title of this thread is "Dropper posts on road bikes"!
Non Rotating Air Cylinders:
First one: It runs on compressed air, you used them, I guess you forgot that it requires 250psi compressed air to operate. Where are you going to install this on the bike??? Or did U use CO2 cartridges??? Hmmm?
One of those with a 5” stroke is listed as .28lbs, for some reason I don’t believe that. But anyway the air compressor is going to be way more, and don’t forget the power supply, either a big battery or a loooong entension cord.
It has a ROUND cylinder of 9/16”diameter, so … round. It doesn’t list the outside dia, but looks something around 1", so maybe it might fit although fastening isn’t really too clear.

Second one: Couldn’t really find that exact one, but this is a review of a similar one available.
It looks like someone distorted the body, cause I couldn’t find any that didn’t have a ….. round bore. Exactly how is this going to fit in the seat tube? I think the same comments on item one apply here, sorry.

Please post specs on all the dropper posts you designed using ‘non rotating round pistons’, post a picture of your bike with one, what were the design perimeters? ha ha ha!!!

Here's the thing; a piston of any kind, be it pneumatic or hydraulic, does not need to be prevented from rotational movement as it actuates linear movement in a system that requires no rotational movement so long as the system itself prevents rotational movement. The system that the linear force is applied to can have this requirement built in. In fact, from a design standpoint, it makes sense for the piston component to not be the rotationally constraining feature. A cylindrical piston can apply linear force against a plethora of geometries that do not allow rotational movement.

For example

Reactions: 1

One Wheel

· #35 · 2 mo ago

craiger_ny said:
Here's the thing; a piston of any kind, be it pneumatic or hydraulic, does not need to be prevented from rotational movement as it actuates linear movement in a system that requires no rotational movement so long as the system itself prevents rotational movement. The system that the linear force is applied to can have this requirement built in. In fact, from a design standpoint, it makes sense for the piston component to not be the rotationally constraining feature. A cylindrical piston can apply linear force against a plethora of geometries that do not allow rotational movement.

For example

It may be beneficial from a weight perspective, if designing an aerodynamic cross section dropper post for a road bike, to combine the piston and the part of the system that prevents rotational motion into a single piece.

Reactions: 1

craiger_ny

· #36 · 2 mo ago (Edited)

One Wheel said:
It may be beneficial from a weight perspective, if designing an aerodynamic cross section dropper post for a road bike, to combine the piston and the part of the system that prevents rotational motion into a single piece.

One way or another the piston is going to push against something, might as well be something non rotational. Non-cylindrical detail parts with tight fit ups (such as a piston and cylinder) that have surface finish requirements that these components typically call for, coupled with the procurement costs of custom seals and required custom composite components of matching geometry pushes costs up exponentially. Versus cylindrical detail parts that can be manufactured conventionally and fitted with shelf item o rings and composite components. Then said piston pushes on an octagonal feature that serves as a linear bearing. Or like you say, the aero geometry. A piston only provides linear motion, it does not provide torsional rigidity, build the rotational constraint into the linear constraint.

Some legit concerns have been brought up in this thread design wise which I dig. All I've done is speculate, it would be cool to see an exploded view or tear down of a current design.

One Wheel

· #37 · 2 mo ago

craiger_ny said:
One way or another the piston is going to push against something, might as well be something non rotational. Non-cylindrical detail parts with tight fit ups (such as a piston and cylinder) that have surface finish requirements that these components typically call for, coupled with the procurement costs of custom seals and required custom composite components of matching geometry pushes costs up exponentially. Versus cylindrical detail parts that can be manufactured conventionally and fitted with shelf item o rings and composite components. Then said piston pushes on an octagonal feature that serves as a linear bearing. Or like you say, the aero geometry. A piston only provides linear motion, it does not provide torsional rigidity, build the rotational constraint into the linear constraint.

Some legit concerns have been brought up in this thread design wise which I dig. All I've done is speculate, it would be cool to see an exploded view or tear down of a current design.

If there's ever a market for road-specific dropper posts then there will be a market for weight-weenie, aero-weenie dropper posts that cost well into 4 figures. I'd be curious to try a dropper post, but I'm too cheap for anything more expensive or proprietary than an off-the-shelf round one.

ogre

Discussion Starter · #38 · 2 mo ago

[QUOTE

One Wheel said:
If there's ever a market for road-specific dropper posts then there will be a market for weight-weenie, aero-weenie dropper posts that cost well into 4 figures.

They already make electronic/cable-less droppers for the MTB crowd, and they are lighter weight. And they cost north of four figures.

tlg

· #39 · 2 mo ago

2

ZOMG... it uses compressed air. 😲

craiger_ny said:
All I've done is speculate, it would be cool to see an exploded view or tear down of a current design.

Google 'dropper post diagram'. There's a ton of drawings and diagrams.

On this one, they're using 3 Index Pins (essentially a spline) to prevent rotation.

This one has 2 Keys

V1 DROPPER POST EXPLODED VIEW & PARTS LIST

AVAILABLE SERVICE KITS INDEX NUMBERS V1 CARTRIDGE HARDWARE KIT: SP1C0031 5,6,13,15,16,18 (DISCONTINUED) V1 ACTUATOR KIT: SP1C0032 17 REBUILD KIT: SP1C0033 8a,8b,9,10,11 TRAVEL SHIMS: SP1C0039 19 SEAT CLAMP KIT: SP1C0043 1,2,3,4 UPPER IGUS BUSHING: SP1C0062 9 CARTRIDGES 150MM: SP1C0030...

www.oneupcomponents.com

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duriel

· #40 · 2 mo ago (Edited)

I still think a tooth and ratchet catch could ultimately be considerably lighter. The seat post would be structural which is required and be the same wt, the ratchet system would just be a saw tooth and flipper, way lighter than pistons, gromments, multiple cylinders and machined air chambers.
On a road bike I would assume you would only need 2 positions, up & down. Forget all the middle locations, you could just have a thumb tab for return.
And your soccer mom van hatch door would stay up cause you returned the support system.

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