[POLL] Hanging an eMTB by it's dropper post in a workshop stand?

[Mikerb]

Equally, physics tells me that if the dropper post can take my 90kg sitting on it, whilst going over rocks, roots and compressions, it can also take the weight of the bike it’s attached to.

As it happens, I don’t hang my bikes by the dropper, but that’s because I lightly clamp the top tubes, which in my bikes are all alloy. I’d have no qualms hanging from the fatter section of a dropper post though if my frames were carbon.

mostly vertical pressure not at an angle.............and if all your 90k was on the saddle the front wheel would be uncontrollable
Seriously what we are looking at in terms of forces with a clamp on the seat post is a best a 200mm section being clamped and the forces acting on it are both vertical and horizontal resulting in a vector of probably 60 degrees and that bears no relation to the forces applied when riding.
If you were trying to bend the dropper post that is the vector of force you would apply with a long lever.........ie in this case more than the front centre of the entire bike. you would get nowhere trying to bend it by sitting on it!!

 

[Tooks]

mostly vertical pressure not at an angle.............and if all your 90k was on the saddle the front wheel would be uncontrollable
Seriously what we are looking at in terms of forces with a clamp on the seat post is a best a 200mm section being clamped and the forces acting on it are both vertical and horizontal resulting in a vector of probably 60 degrees and that bears no relation to the forces applied when riding.
If you were trying to bend the dropper post that is the vector of force you would apply with a long lever.........ie in this case more than the front centre of the entire bike. you would get nowhere trying to bend it by sitting on it!!

Measure your seat post angle, it isn’t vertical. Even less so when the rear suspension is under compression.

If people were wrecking dropper posts by merely clamping them in work stands, the forums would be full of it.

I’d expect any branded dropper to have been designed around its statement of intended usage, and using it on the trail puts far more stress through it than it supporting 25kg of bike. They are overbuilt, and designed to resist repeated bending moments.

 

[Mikerb]

Measure your seat post angle, then come back and tell us it isn’t straight.

If people were wrecking dropper posts by clamping them in work stands, the forums would be full of it.

I’d expect any branded dropper to have been designed around its statement of intended usage, and using it on the trail puts far more stress through it than it supporting 25kg of bike. They are overbuilt.

if you follow any forums, dropper post failure is pretty common........even the most expensive ones.

 

[Tooks]

if you follow any forums, dropper post failure is pretty common........even the most expensive ones.

Not by it supporting a bike in a workstand though?

Wear and tear, seal failure and hydraulic piston failure more common.

Droppers are just fancy height adjustable office chair supports at the end of the day.

 

[militantmandy]

no...I stand on the pedals to climb

I think you're doing e bikes wrong

 

[Nomad1]

I don't clamp to my dropper personally . I'm not a big fan of the idea and haven't found the need to
real either Not that you can't but, unless I need to it's a no for me.

 

[Stihldog]

I remember posting similar pictures a few years ago and I’m still doing the same thing. Takes about 11 seconds to put things in place (11 seconds that I’ll never get back).

AXS Reverb dropper and the stem while using a Saris car rack bar. It’s a good hight for charging, servicing and storing. It only fell once when the adjustable clamps on the Park Tool stand slid. I tightened that mofu after.

 

[Bummers]

False crossbar every time. It cups the headset well, I didn't notice any undue pressure on the wires.

 

[RipGroove]

False crossbar every time. It cups the headset well, I didn't notice any undue pressure on the wires.

View attachment 121221

That the Halfords one or Saris one?

 

[Andy__C]

Even though it feels weird and I do worry about it........ I clamp the dropper.

Sometimes you just have to have the leap of faith that if the pros are mostly doing it, it's OK.

CBA spending another £30 on piece of equipment to make me feel better about something else regarding the bike - "must spend must have" culture is already too much in this game!

 

[RipGroove]

I'm certain the dropper won't break, I was more concerned about prematurely wearing out the internal bushes and making it sloppy over time. The Pros wouldn't have to worry about longevity as much as we do.

 

[Spin]

E:

 

[irie]

I'd never hold a bike on a workstand by its dropper post, if only because a dropper post is designed for top weight support, not for holding weight from underneath IYSWIM.

 

[Paul Mac]

I just rest the bike on its seat rails and don't even clamp the seat post when using my work stand, front wheel is on the ground but rear is lifted to carry out most maintenance.

 

[Christurbo]

E… None.

E-Bikes are heavy!

 

[RustyIron]

I've always clamped on the top tube. If my bikes were so delicate that they would crumble to pieces, then they probably wouldn't be suitable for the other abuse I subject them to.

 

[steve_sordy]

no...I stand on the pedals to climb

I don't and my dropper is still fine.
But clamping on the dropper stanchion offends me so I just would not do it.

 

[irie]

Measure your seat post angle, it isn’t vertical. Even less so when the rear suspension is under compression.

If people were wrecking dropper posts by merely clamping them in work stands, the forums would be full of it.

I’d expect any branded dropper to have been designed around its statement of intended usage, and using it on the trail puts far more stress through it than it supporting 25kg of bike. They are overbuilt, and designed to resist repeated bending moments.

The point is that dropper seat posts are designed to support loads of perhaps 120kg for "larger" riders from above ...

 

[deksawyer]

Why do you all care, because you're gonna replace that dropper anyway, whether you need to or not!

 

[Mikerb]

I think you're doing e bikes wrong

There is no right and wrong..................just success or failure. I have no problem on the steepest rocky climbs.......ipso ergo QED!!

 

[Mikerb]

I don't and my dropper is still fine.
But clamping on the dropper stanchion offends me so I just would not do it.

and mine...never had to repair or replace a dropper!

 

[militantmandy]

There is no right and wrong..................just success or failure. I have no problem on the steepest rocky climbs.......ipso ergo QED!!

I jest of course!

 

[Bummers]

That the Halfords one or Saris one?

Halfords, was about £20.

 

[Bummers]

Even though it feels weird and I do worry about it........ I clamp the dropper.

Sometimes you just have to have the leap of faith that if the pros are mostly doing it, it's OK.

CBA spending another £30 on piece of equipment to make me feel better about something else regarding the bike - "must spend must have" culture is already too much in this game!

For the sake of £20 it's piece of mind. A dropper post is a minimum of £100 up to £400+. Just not worth risking it.
Also it's much easier to balance and position the bike using a false crossbar.
Each to their own though.

 

[Tooks]

The point is that dropper seat posts are designed to support loads of perhaps 120kg for "larger" riders from above ...

Source please?

You mentioned it before, and I ignored it, but now you’ve quoted me…

It’s not just loads ‘from above’, your seat tube angle is not vertical, so the loads are also lateral, and even steeper under suspension compression.

You really think a dropper post, and the bit of the frame it inserts into, is designed to take 120kg, plus any dynamic loads in excess of that, but suddenly won’t be able to handle holding up a 25kg bike in a work stand?

Personally, I don’t clamp the seatpost to work on the bike, but I wouldn’t worry about doing so albeit I’d extend the lower out of the frame a bit more and clamp to that as it just seems mechanically sympathetic. I do weigh my bikes by hanging the bike from the saddle, as does Rob on his YT videos.

My stand and bikes hang from the top tube just fine to work on, and I find the crossbar things that people are using do restrict access to the bike when I want to work on the headset or a dropper cable.

Incidentally, those crossbars also attach to the seat post from peoples pics, the post is still supporting weight ‘from below’ which doesn’t really support your theory either. EMTB would be full of posts saying my bike just fell onto the ground and the dropper is still in the work stand clamp…

 

[irie]

Source please?

You mentioned it before, and I ignored it ...

As I will also ignore it.

 

[Beaker2135]

I voted E
I use method as @Mikerb mainly because it is easier to lift the bike into the bars than try to hold it with one arm while I close the clamp
That said I’m 100kg all up and the post copes with that without any problem so the main risk would be scratching the Kashima coating

 

[Tooks]

As I will also ignore it.

Thanks for the discussion!

I think what your concerned about is that you think dropper seat posts aren’t as strong under a tension load as they are under compression or bending forces, and you could be correct.

A dropper post is always under a tension load though as the hydraulics default state are always pushing the top tube upwards to the seat. A dropper post always wants to be up, so the mechanism to resist that tension load must be robust.

If you’re going to clamp a dropper seat post, then I’d always clamp the lower part, because the wider diameter tube is stronger anyway, and you’re clamping closer to the frame so minimising rotational forces.

Now, where’s the latest ‘what tyre’ thread?!

 

[Christurbo]

What I take from this post is that we all have different ways of doing the same thing based upon practicalities and views of risk.

There are no official guidelines (as far as I know). Assess the risk and do what you think is right.

Good luck!

 

[Tooks]

What I take from this post is that we all have different ways of doing the same thing based upon practicalities and views of risk.

There are no official guidelines (as far as I know). Assess the risk and do what you think is right.

Good luck!

Yes, this should always be an individuals approach.

I come at it from the view of trying to minimise the number of things that we EMTB’ers seem to needlessly worry or obsess over!