Marking a brompton seatpost.

[Arch]

Yet another newbie-Bromist query...

Any good ways of marking a seatpost so that I can set it just right each time I unfold?  Currently, I'm tending to underestimate, riding three yards, stopping, and raising it a bit more.

It's chromed, and I assume any mark made in pen would soon get rubbed off with the post going up and down, and any physical scratch etc would be a rust magnet.

My boss at Velo Vision did suggest something with a piece of string left attached to the saddle...

[rogerzilla]

How tall are you?  Ideally you get the right length seatpost and adjust the saddle clip on the seatpost (there is an inch or two of adjustment) until you get the correct height with the post pulled right up to the stop.  This isn't always possible.

[border-rider]

You quickly get a feel for how far to pull it out

Oddly, my old one had the post in a few cm; the replacement has the post fully out.  The old one didn't have an extended seat post (or at least, I didn't order one when I bought it)

[Biggsy]

Marker pen ink survives a few up-and-downs.  It only takes a couple of seconds to re-mark it to keep it bold.  I carry a marker pen in my S-bag.

Paint tends to flake off.  A physical scratch won't rust if the post is aluminium or titanium - but I'm not sure it would be a good idea anyway.

[Arch]

How tall are you?  Ideally you get the right length seatpost and adjust the saddle clip on the seatpost (there is an inch or two of adjustment) until you get the correct height with the post pulled right up to the stop.  This isn't always possible.

5' 3" with legs on the short side...

I might see how well I get on with marker for now, and I expect I'll get the habit eventually.

[Ariadne]

A blob of nail polish stays there for ages - I never managed to get to 'know', I needed a marker.

[Kim]

Alternatively, get to know where the saddle sits relative to your hip bone.  Depending on bottom bracket height this may or may not be helpful.

[rogerzilla]

The Rolls-Royce solution is to cut down the seatpost to the perfect length and have an engineering shop bellmouth the lower end again.  This will probably ruin the chrome, but may be worth trying on an alu or Ti post.

[LittleWheelsandBig]

It is a doddle to flare a cutdown steel post, I did it years ago. No problems with the chrome flaking or the steel corroding significantly.

I'm less confident that I could do it with an Al post but haven't tried it. The wall is thick and the nickel plating is demonstrably more fragile than the chroming on a steel post.

[Biggsy]

I wouldn't cut the post down.  What if you want to let someone taller ride it, or what if you fit a slimmer saddle?

*goes to shop to buy nail varnish, expecting funny looks*

[chagzuki]

Can't you just add a bit of thick tape positioned such as to do what the flare would, i.e. something that's thick enough so that you can feel a notch as you pull the seat post up?

[Arch]

Can't you just add a bit of thick tape positioned such as to do what the flare would, i.e. something that's thick enough so that you can feel a notch as you pull the seat post up?

That's an idea, but I may sometimes want to lend it to MFWHTBAB, who is a bit taller than me, so yes, the seat post may occasionally need to come up higher.

I might even have a bottle of nailvarnish at home, unless it all went in my last clearout.

[LittleWheelsandBig]

I wouldn't cut the post down.  What if you want to let someone taller ride it, or what if you fit a slimmer saddle?

There is a range of saddle heights available with the Pentaclip on the seatpost. I cut the (extended) seatpost to suit Mrs LWaB (standard post too short) and could have lifted the saddle more than a cm using the Pentaclip. A replacement seatpost is not that expensive.

[Si]

put seat post up to correct position.  tie a bit of string to a saddle rail, tie the other end to the frame.  Next time you unfold just pull the saddle up until the string is tight and job's-a-good-un

[rogerzilla]

Doesn't the string drag on the ground and get caught up when unfolding?

[Arch]

Doesn't the string drag on the ground and get caught up when unfolding?

Well, I wondered, but looking at it, if it's attached at both ends, it might work. Bear in mind, I have short legs, hence not a lot of seatpost extension, hence not a long piece of string.

But then it would need to be detachable at one end to allow MFWHTBAB to borrow it on occasion, as he needs the seat up more.

[Si]

Doesn't the string drag on the ground and get caught up when unfolding?

Not if you use folding string.

[robgul]

I don't have a Brompton - but would have no hesitation in making a minute scratch on the seatpost as a marker

 .... as an aside, a friend just bought a Dahon and that has a "ruler" printed on the seatpost and, presumably, anodized ... I rode the bike (I'm about a foot taller than him, no problem for him to reset the seattube to his preferred scale setting.  Something that Brompton might look at?

Rob

[Biggsy]

.... as an aside, a friend just bought a Dahon and that has a "ruler" printed on the seatpost and, presumably, anodized ... I rode the bike (I'm about a foot taller than him, no problem for him to reset the seattube to his preferred scale setting.  Something that Brompton might look at?

I hope so.  That would be good.  Even the Ken bikes in London have a scale marked on the seatpost - albeit a chunky one - and also a line to help you get it centred.

[Sergeant Pluck]

Well Brompton still don’t put markings on their seat posts. Have there been any solutions developed since 2011?

I have a Brompton saddle height insert on the way, which presumably will take care of matters for the taller of the two users of the Brompton in question, but I need a way to mark it for the smaller person.

[Jurek]

Well Brompton still don’t put markings on their seat posts. Have there been any solutions developed since 2011?

I have a Brompton saddle height insert on the way, which presumably will take care of matters for the taller of the two users of the Brompton in question, but I need a way to mark it for the smaller person.

I'm lucky in as much as the ideal seat post height for me is when the post is pulled out to max.
However, I think that Robgul's suggestion above is probably the best.
A tiny scratch, with a hacksaw or whatever, then get some ink into the scratch - from a permanent marker - should be fine without compromising the integrity of the seat post.

[LittleWheelsandBig]

Marking the Brompton seatpost is one thing but wear of the seatpost sleeve is another. The sleeve within the frame is soft plastic (Nylon?) to avoid any need for grease between seatpost and frame and to provide a perfect fit between a round post and a distorted frame tube.

Any disruption in the seatpost’s surface will progressively wear away the sleeve every time the post is raised or lowered. Even the apparently-smooth surface texture of an aftermarket carbon seatpost prematurely wears the sleeve. A large scratch on the post will do the same. A short scratch, ideally lined up with the compression slot, should limit the problem.

[Blade]

I'd be tempted to use a centre punch to mark the seatpost where it meets the frame at it's correct extention.

Then a spot of black marker or nail varnish added to the indentation.

Any slight raising caused by the centre punching could be easily removed with fine emery paper, or if using nail varnish as a marker, then you probably own an emery board.

[drossall]

Get a saddle height insert, as you say.

Cheap plastic part that sits in your seat tube. You cut it to length to suit your desired saddle height. The flaring on your existing seat post hits the bottom of the insert and so stops sooner than it otherwise would, at your ideal height. Just err on the cautious side. Usual rule - you can cut more off (I did), but not put it back!

Or, for two riders, I've got an after-market graduated seat post in the shed. Never used. You're welcome to try it, as I shan't use it. I bought it because I wanted a black one, but didn't realise that it wouldn't be flared (so the seat insert won't work). It's a bit longer than the standard posts I normally use. I think it's alloy, can check.

[PaulF]

Get a saddle height insert, as you say.

Cheap plastic part that sits in your seat tube. You cut it to length to suit your desired saddle height. The flaring on your existing seat post hits the bottom of the insert and so stops sooner than it otherwise would, at your ideal height.

Just err on the cautious side. Usual rule - you can cut more off (I did), but not put it back!

Or, for two riders, I've got an after-market graduated seat post in the shed. Never used. You're welcome to try it, as I shan't use it. I bought it because I wanted a black one, but didn't realise that it wouldn't be flared. It's a bit longer than the standard posts I normally use. I think it's alloy, can check.

I think Sergeant Pluck has the insert already; which suits the taller rider but he wants to mark a second, lower, position for a shorter rider. Can’t help further because I also just use it fully extended.