Clamping on dropper post

[DieselnDust]

9 minutes ago, MTBRIDER1234 said:

To each their own. I know my dropper will get more damaged by grit when riding, so I do not put a cloth in the clamp. Also a cloth sometimes limits available friction, so the bike will move around in the clamp, which is irritating to work on.

But when working on someone else’s dropper I’ll wrap it in silk dipped in the highest quality aloe Vera because you know people lose their **** if their bike isn’t treated like fragile crystal ,

 

is be more concerned with clamping the fragile carbon frames in a bike stand. They scratch more easily too

Edited June 8, 2022 by DieselnDust

[MTBRIDER1234]

Just now, Quagga said:

I get what you are saying

 

So the bike is front wheel low. But setpost is not in the center of gravity of teh bike so there will still be a bit of force?

Yip, the front wheel will be low. Also the force is spread through the dropper if clamped properly, so all will be fine

[MTBRIDER1234]

Just now, DieselnDust said:

But when working on someone else’s dropper I’ll wrap it in silk dipped in the highest quality aloe Vera because you know people lose their **** if their bike isn’t treated like fragile crystal 

Yet they will put it on the floor drive side down, change gears when not pedalling, never lube their chain, the list goes on...

[DieselnDust]

18 minutes ago, Quagga said:

If clamp is on the stanchion like in this pic

Does the heavy front not pull down and thus could bend it ?

 

Let’s say you have 15kg 1m from the stanchion clamp zone. That’s a moment of 150N/m

That’s equivalent to  weight of 100kg at 15cm

these stanchions don’t permanently deform under either static load and the rider is a worse scenario because there’s a dynamic component and cyclic loading to be applied and still they don’t bend. 
tou have nothing to worry about

[ChrisF]

55 minutes ago, Quagga said:

What are your feelings on clamping a bike on the dropper post stanchion?

 

From what I have read, it is a NO NO!

I recently had an experience where the shop mech wanted to clamp my bike on the dropper stantion. I told nim "no way"

In my view it does not matter how soft the bike stand clamps are, it could damage the stantion.

It gets better or(  worse), my bike is a 27KG Ebike, so all that force is now concentrated on the stanchion/ dropper interface. Surely it is / was going to bend something and cause it to wear out over time?

 

What do you think?

 

What do you guys think?

 

I recently read up on this .... as I have the same bike, and share your concerns.

 

Seems it is common practice by workshops to clamp onto the dropper.  The ONLY word of caution I got was to make SURE the dropper is FULLY extended.  Apparently that upward force on a partially raised dropper can cause some damage to the dropper.

 

 

At home .... the top tube (that last horizontal bit) of my bike "rests" on the clamp, and then the handlebars is supported with a "hanger".

[DieselnDust]

28 minutes ago, ChrisF said:

 

I recently read up on this .... as I have the same bike, and share your concerns.

 

Seems it is common practice by workshops to clamp onto the dropper.  The ONLY word of caution I got was to make SURE the dropper is FULLY extended.  Apparently that upward force on a partially raised dropper can cause some damage to the dropper.

 

 

At home .... the top tube (that last horizontal bit) of my bike "rests" on the clamp, and then the handlebars is supported with a "hanger".

Yes if the post isn’t fully extended the negative pressure on the hydraulics can cause internal leakage and the post won’t fully extend after or develop squishyniss.

without a vent valve of sorts the only way to repair this is with a new cartridge or a service for a unit like the Reverb or Transfer

Edited June 8, 2022 by DieselnDust

[droo]

2 minutes ago, DieselnDust said:

Yes if the post isn’t fully extended the negative pressure on the hydraulics can cause internal leakage and the post won’t fully extend after or develop squishyniss.

without a bent valve of sorts the only way to repair this is with a new cartridge or a service for a unit like the Reverb or Transfer

Almost - the oil boils at low pressure and you end up with gas in what's meant to be incompressible. Boing boing.

Those seals take 500 odd PSI in positive pressure, that 14psi (at most) of vacuum shouldn't make them leak.

[Steady Spin]

1 hour ago, Quagga said:

If clamp is on the stanchion like in this pic

Does the heavy front not pull down and thus could bend it ?

 

If the weight of the bike will bend a post then my fat ass would have bent it a long time ago. 

[Steady Spin]

Both bikes get clamped on the post once a week for pre-ride inspection and lube if needed. No cloths or anything. I make sure the clamps are 100% clean before mounting. 

More than 2 years of doing this and not even the slightest of marks on the posts. I’ve also left the bike dangling from the post for a couple of days when shocks or forks go in for a service. 

Dropper posts aren’t made of glass. They can take it. 

[DieselnDust]

15 minutes ago, droo said:

Almost - the oil boils at low pressure and you end up with gas in what's meant to be incompressible. Boing boing.

Those seals take 500 odd PSI in positive pressure, that 14psi (at most) of vacuum shouldn't make them leak.

Remember that positive pressure deforms the seal in a direction that creates a  better seal. Negative pressure does the opposite but you are also correct in that oil will boil or any water even if a tiny amount will boil first. We can also bleed those things to our hearts content there will always be a tiny bit of air in them which gets drawn out under vacuum. So lots going on in there  which = phone droo

[Jbr]

2 hours ago, Quagga said:

What are your feelings on clamping a bike on the dropper post stanchion?

 

From what I have read, it is a NO NO!

I recently had an experience where the shop mech wanted to clamp my bike on the dropper stantion. I told nim "no way"

In my view it does not matter how soft the bike stand clamps are, it could damage the stantion.

It gets better or(  worse), my bike is a 27KG Ebike, so all that force is now concentrated on the stanchion/ dropper interface. Surely it is / was going to bend something and cause it to wear out over time?

 

What do you think?

 

What do you guys think?

I do no give a f***. Haven't since I got my dropper, no problems in I think 2+ years, the thing is bulletproof.

I wouldn't clamp it tight on the lower part though (obviously), but I've seen it done on youtube vidéos

Edited June 8, 2022 by Jbr

[droo]

11 minutes ago, DieselnDust said:

Remember that positive pressure deforms the seal in a direction that creates a  better seal. Negative pressure does the opposite but you are also correct in that oil will boil or any water even if a tiny amount will boil first. We can also bleed those things to our hearts content there will always be a tiny bit of air in them which gets drawn out under vacuum. So lots going on in there  which = phone droo

For U cup seals I get this, but for O rings as well?

[droo]

Back on topic - when I clamp a bike in a stand I mark the height of the post and pull it out until there's enough lower to clamp that in the stand. Takes less than a minute in most cases and saves any possible heartache. Particularly when removing SRAM or RF cranks, BBs, and anything that requires flogging, which is more than we'll tell you...

[DieselnDust]

1 hour ago, droo said:

For U cup seals I get this, but for O rings as well?

Yeah orings as well but less susceptible. Groove design and tolerance is important here and I see some …… questionable engineering….

[DieselnDust]

55 minutes ago, droo said:

Back on topic - when I clamp a bike in a stand I mark the height of the post and pull it out until there's enough lower to clamp that in the stand. Takes less than a minute in most cases and saves any possible heartache. Particularly when removing SRAM or RF cranks, BBs, and anything that requires flogging, which is more than we'll tell you...

I have broken one or two pool net poles…..

[ChrisF]

5 minutes ago, DieselnDust said:

..... I see some …… questionable engineering….

 

Had this discussion today ....

 

Some heavy industrial is being installed now where it starts showing "questionable engineering" when we do commissioning tests !! 😵🤦‍♂️