Seatpost suitable for quill modification?

Discuss light weight issues concerning road bikes & parts.
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strandsatt
Posts: 20
Joined: Tue Oct 12, 2010 6:11 am

by strandsatt

Hi,

I'm currently riding a Moser Leader AX from '93 and it has a somewhat unusual seatpost solution. Instead of a cut in the frame and a clamp, it requires a quill seatpost. Now these are somewhat rare and when they crop up they're expensive and heavy.

So it's wintertime and I need something to keep me from going nuts from lack of riding. So I thought I'd make a lightweight quill seatpost!

Now the only problem has been finding suitable starting material.

There are essentially two solutions (and a non solution) out there today:

Image
#1: The Campagnolo solution, with a diagonal screw pulling the quill assembly upwards. Incidentally pictured with the same frame as I have, though in a different colourscheme.

Image
#2: The solution on my current seatpost (not mine pictured), which is a bit finicky, since I have to remove the saddle to remove/adjust the seatpost.

Image
#3: Actually just found this one, but would be even weirder and require a reaaaallly long allen key. I assume this is for a bmx or similar.

Despite its drawbacks, for ease of manufacture, I was planning to go with #2. I could even use the assembly on my current seatpost (which is in bad condition and hovering around the 350g mark for 170mm).

Ideas? Thoughts? It's hard to find pictures of seatpost taken from the top without cradle assemblies and collectively (and probably individually) you've seen a lot more seatposts than I have.

Any input greatly appreciated. In terms of styles, zero to little setback would be preferable and material I'm not sure yet. Carbon would be really nice, if there's a good way to do the conversion.

shimmeD
Posts: 371
Joined: Thu Jun 28, 2012 10:52 pm
Location: eNZed

by shimmeD

I've seen (from this forum) a Thomson solution from English Cycles but doesn't get you away from having to remove the seat. I'm sure you have considered a simple clamp (as commonly used on alloy frames) as probably the lightest, and over the seat-tube (as commmonly used on carbon frames) which Rob English also makes.

by Weenie


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tommasini
Posts: 1296
Joined: Sun Nov 02, 2003 6:48 am
Location: Central USA
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by tommasini

How about considering putting slot in the seat tube (with round hole at the bottom to reduce a chance of a stress riser) and using an alu clamp/bolt combo......could even cut the seat tube down to a more "traditional" height.

With that modification and a 10 - 12 gram clamp/bolt you'd have availability to the lightest seatposts (around 140 grams) to classy traditional models that fit that era of frame (around 200 grams assuming a non-sloping top tube)....even carbon ones for the lightness or looks......

If that goes against your wishes for the frame I understand....but this is weight weenies!!

strandsatt
Posts: 20
Joined: Tue Oct 12, 2010 6:11 am

by strandsatt

Thanks for the replies!

Had not seen the English - Thomson solution, not sure what's going on there, but seems interesting and the post looks pretty enough in silver.

Cutting a slot in the frame is not really an option, I think it is part of what makes this bike what it is. The clean transition from seattube to seatpost is really nice imo.

Looking at the Thomson it seems like it could be a good option actually. Depending on what the cradle seat looks like I could cut a slot in the cradle to fit the bolt head, which would make the rest of the conversion a formality. Though I suspect that the cradle seat is hollow, which would put me back at square one.. Impossible to find photos from the right angle!

shimmeD
Posts: 371
Joined: Thu Jun 28, 2012 10:52 pm
Location: eNZed

by shimmeD

If you search English Cycles you can find a thread by Bmanx (I may not have the correct spelling for this weenie) detailing his English build including a pic of the Thomson. Better still you may get a post from him, with more lurid details.
I have an Elite post and both upper and lower cradles are one-piece construction, the post itself hollow the whole length. I don't see why you couldn't drill either/both pieces for allen key access (without detrimentally compromising integrity - cavaet!), the saddle limiting the length of your tool however. I think you may have to forgo a spot of convenience for the clean look. Again Bmanx is your man.
Less is more.

by Weenie


peruffo
Posts: 167
Joined: Sun Oct 26, 2008 3:12 pm

by peruffo

I made this one for a customer, he is 204 cm tall, so he needed a longer quill seatpost than the usual 230 mm Campy Record we have on stock. It came just under 250 gr (320 mm lenght), there is a 260 mm aluminum tube inside, attached to the perpendicular alu rod inserted in the wedge, pulled by the titanium bolt at the top. With a lighter clamp mech, and normal (road bike) lenght seat tube, you could go down to 210-220 gr.

BTW I have two Moser frames and I slotted them to save the hassle of making one like this...
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