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Seatpost height reference tips?

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Seatpost height reference tips?

Old 10-06-15, 11:06 AM
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RubeRad
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Seatpost height reference tips?

So, lacking a dropper post, sometimes my wife & I use the QR to drop our seats a couple inches for scary descents, and then put them back up later. Also, we swap bikes sometimes, and we need different seat heights. So it would be useful to have reference marks on our seatposts so we can set it back to the same place easily. Marker doesn't seem to be very permanent. Tape can only mark the highest position on the seatpost (lowest seat height). Any other bright ideas? Would scoring with a knife or file be a bad idea?
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Old 10-06-15, 11:24 AM
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Lightly score with a small file. No, it shouldn't cause any damage.
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Old 10-06-15, 11:37 AM
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Aluminum posts? Not ultra-light? Like corrado33 says, scoring them lightly won't hurt anything. (Look at how many posts are out there with serious scoring from seat tubes that need reaming. You know, marked with the letters VVVVVVVVV from working the post down.) It is probably best to score the back or side and refrain from scoring the front because posts break when you hit a huge bump and try to bend the post back. A score in front would be removing material from the tension side, not the best idea.

Ben
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Old 10-06-15, 11:44 AM
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I wouldn't use a file, but a marker or pen of some type. Maybe the wife and you can have different colors. These would wash off with ISO but otherwise wouldn't smudge.

Sakae made a seatpost back in the day that had reference measurements on each side, cm and inches. You could easily switch back and forth. There is one on eBay right now but its a 26.8mm....
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Old 10-06-15, 11:50 AM
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Got a black permanent sharpie?
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Old 10-06-15, 12:16 PM
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Originally Posted by Camplex View Post
I wouldn't use a file, but a marker or pen of some type. Maybe the wife and you can have different colors. These would wash off with ISO but otherwise wouldn't smudge.

Sakae made a seatpost back in the day that had reference measurements on each side, cm and inches. You could easily switch back and forth. There is one on eBay right now but its a 26.8mm....
Originally Posted by Leebo View Post
Got a black permanent sharpie?
Seatposts should be lubed with grease. I don't think markers would hold up to grease very well.
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Old 10-06-15, 12:25 PM
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Sharpie make an 'industrial' model that claims to write on oily surfaces, resist chemicals, heat, nuclear annihilation etc: Industrial Fine Permanent Marker | SharpieUSAStore

Staples and a large, Seattle-based internet retailer carry them.
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Old 10-06-15, 12:26 PM
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Do it all the time. Clean the seatpost. Then mark, then grease. Works well.
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Old 10-06-15, 12:30 PM
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Originally Posted by Leebo View Post
Got a black permanent sharpie?
Sharpies work pretty good if the post doesn't have lot of grease on it.
And you can use a silver Sharpie on a black post.
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Old 10-06-15, 12:41 PM
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Lightly score with a small file. No, it shouldn't cause any damage.
But it does , scratches become Stress risers in metals , particularly aluminum

and the scratch becomes a fracture line . [ with a 200+ pound rider on the post top end]


I have No Marks on My Brompton* seat post , I do know by experience when it feels too low,
and I stop and raise it then.

with a QR lever which they ^ all do , It is a simple task. ( To slow slipping down I use 2, 1 QR grips the post itself)

*(chromed steel)

I pull it up to where the edge of the saddle touches my Hip in a remembered spot, and its close enough

Last edited by fietsbob; 10-06-15 at 05:03 PM.
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Old 10-06-15, 02:10 PM
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Originally Posted by fietsbob View Post
with a QR lever which they ^ all do , It is a simple task.
Yes, it is a simple task, but the more often you have to repeat a simple task, the more you want it to be as absolutely simple as possible (or automated, which in this case, no I do not want to design/build a dropper post with multi-position memory -- or buy a dropper post!)

We have tried sharpies (not industrial grease-friendly sharpies) in the past, they did not last long. Plus in this case one of the seat posts in question is black.

I like the idea of lightly scoring on the back only; it makes sense that it is less significant in the compression area than the tension area. Also, for the black post, I guess scoring will just remove paint instead of metal anyways.
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Old 10-06-15, 03:31 PM
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Superglue small neodymium magnets at the appropriate two heights inside the seatpost, and carry a third as a 'detector'?
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Old 10-06-15, 04:51 PM
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Nice. Let that be a cue to start rube-goldberging this question...
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Old 10-06-15, 05:03 PM
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Originally Posted by RubeRad View Post
Nice. Let that be a cue to start rube-goldberging this question...
Attach a string to the bottom of the seatpost with glue or tape. Run a string out the drain hole in the bottom bracket (good luck). Mark string where you need to have marks. Therefore the marker should stay on the string and you won't have to score your seatpost.

Alternatively, hang a plumb line off of the back of your seat (on the rails). Mark the line with a point of reference further down the bike, fold in to saddle bag when not in use.

Even better! Attach a guitar G string (small one) to the seatpost of your bike. Further down the bike wrap the line around something so it won't move, hold it tight. Then, get a guitar tuner and pluck the string. Each seat height could correspond to a different note. (Because the string will get shorter and longer as you raise or lower the seat. That's assuming you can hold with constant tension.

You're welcome.
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Old 10-06-15, 05:08 PM
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OK, I wasn't entirely serious but now I'm starting to think it might work. Epoxy rather than superglue would give you a better shot at getting the placement right. There's a bunch of places you could keep the third magnet.

If you want to go the musical route, no need for a string. Add a reed and you can play the seat tube / seatpost a bit like a trombone. If you have perfect pitch you're done.
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Old 10-06-15, 05:09 PM
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Brompton's telescoping 2 stage seat post can be Rube Goldberg ed with an internal cable ,

you pull the post lower section up until the flared end stops against the plastic shim, in the frame

then the cable length will be pre adjusted inside to only come up so far ,

until the length of the cable stops it's extension.


You can do that with a regular seat post , the bottom of the cable is trapped by a longer Upper water Bottle Bolt.

upper end is wedged inside the seat post.

Last edited by fietsbob; 10-06-15 at 05:32 PM.
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Old 10-06-15, 05:14 PM
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That only gives you one position though. RubeRad needs two.

Perhaps a cable split by a spring, extension limited by another piece of cable; position one is when the cable just goes tight but without extending the spring any, position two is when the cable prevents further spring extension.

One of those tiny self retracting tape measures mounted under the saddle might be easier.
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Old 10-06-15, 05:19 PM
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I use sharpies, but they do rub off. It's not that tough to stop and re-adjust a couple times. Maybe nail polish?
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Old 10-06-15, 05:32 PM
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Originally Posted by Earl Grey View Post
That only gives you one position though. RubeRad needs two.
Actually potentially three; regular & dropped for the wife, plus regular for me.

I'm also thinking now, tape for dropped, and remember a certain number of fingers difference for the regular position?
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Old 10-06-15, 05:34 PM
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Tape measure in your pocket is too simple.
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Old 10-06-15, 06:16 PM
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Tiny bit of diffrent color finger nail polish on the post? Not sure if it would cause problems with makeing the post to thick. But i would think it shouldnt add enough to do anything
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Old 10-06-15, 06:40 PM
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Originally Posted by Earl Grey View Post
Sharpie make an 'industrial' model that claims to write on oily surfaces, resist chemicals, heat, nuclear annihilation etc: Industrial Fine Permanent Marker | SharpieUSAStore

Staples and a large, Seattle-based internet retailer carry them.
Thanks for the thought and the link. Just now ordered some from Amazon.
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Old 10-06-15, 06:55 PM
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Originally Posted by Earl Grey View Post
Superglue small neodymium magnets at the appropriate two heights inside the seatpost, and carry a third as a 'detector'?

That is just exactly perfect
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Old 10-06-15, 08:33 PM
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This could be addressed with the simplest of story sticks.
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Old 10-06-15, 09:03 PM
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Originally Posted by fietsbob View Post
Tape measure in your pocket is too simple.
+1..... I thought no one was ever going to post the obvious. You don't even need a tape measure. You can score marks on a tire lever.
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