DIY shave 110 g off a seatpost!

Discuss light weight issues concerning road bikes & parts.

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Lucendi
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Joined: Fri Jul 19, 2019 10:37 pm
Location: Sweden

by Lucendi

This Basso Diamante seatpost weighs a hefty 233 grams!

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It has a proprietary Basso clamping system and an odd tube shape, and no aftermarket alternatives are available.

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So let's fix this by installing a traditional non-proprietary cradle and yoke clamping system.

First I scan the cross section and make a 3D-model of the seatpost;

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I place the cradle and pin into the model and work out the angles and placements.

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Then I make a guide block that clamps around the seatpost with outlines of the holes for the cradle and pin that will be cut. It has a small gap in the front where the clamping action happens, thus pushing the seatpost back against the rear of the block and perfectly aligning the seatpost.

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And I print the guide block.

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Then I print a sanding block that will have a diameter of 27,2 mm with sand paper wrapped around it;

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And now everything is ready for cutting!

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Using a rotary tool with a cutting disc I safely cut the carbon without risk of fraying the fibers.

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I then make the hole for the pin and slowly widen it until it is 10mm in diameter.

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I file slowly while checking the shape and diameters of the holes using drill bits in various sizes as gauge blocks. Working my way up from 8,5mm to 10 mm until the pin (10 mm) fits snuggly.

And this is the final result!!

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All the hardware was bought as spares for a Schmolke TLO seatpost, with a 27,2 mm cradle and a 31,6 mm pin.

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A massive 110 gram weight saving was achieved! Bringing the weight down from 233 grams to 123 grams!

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Last edited by Lucendi on Thu Feb 03, 2022 4:52 pm, edited 1 time in total.

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MrCurrieinahurry
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by MrCurrieinahurry

Real weight weenie behaviour I love it

Basso Diamante super record EPS 12
BMC slr01 ultegra Di2

Formerly known as Curryinahurry

by Weenie


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mrlobber
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by mrlobber

Awesome
Bikes I know something of:
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jayjay
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by jayjay

Good work!

rudye9mr
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by rudye9mr

Next level mod!!!!

Butcher
Shop Owner
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by Butcher

Old school weightween project, I like it.

kode54
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by kode54

Excellent step-by-step how-to! Great job!
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overdriven98
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by overdriven98

it rise the question why the hell that all the major manufactory using unnecessarily heavy duty clamp and yoke on the seat post..

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eucalyptus
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by eucalyptus

Nice, but it looks very short and it had -15mm offset initially, now it has zero offset. Basso frames are made for offset seatposts, do not see how you can ride without one.

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Lucendi
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by Lucendi

eucalyptus wrote:
Thu Feb 03, 2022 5:07 pm
Nice, but it looks very short and it had -15mm offset initially, now it has zero offset. Basso frames are made for offset seatposts, do not see how you can ride without one.
The effective seatpost length lost is about 95 mm if measured from the bottom-of-the-seatpost to the underside-of-the-saddle-rails. It is just long enough to fit like the original seatpost.

An alternative would have been to cut off 95 mm from the bottom, which would have saved 34 grams. With that background the weight saving is about 76 grams from switching out the clamping system.

10 mm setback hardware can be fitted if setback is an issue.

takolino
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by takolino

Nicely done! I like that you did this with mostly available tools. The 3D printed jigs are very helpful. I did this a couple of years ago on a 3T Strada and got similar weight savings. The build is in the gallery. Strada has a zero offset post so it was an ideal case.

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eucalyptus
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by eucalyptus

Lucendi wrote:
Thu Feb 03, 2022 8:18 pm
eucalyptus wrote:
Thu Feb 03, 2022 5:07 pm
Nice, but it looks very short and it had -15mm offset initially, now it has zero offset. Basso frames are made for offset seatposts, do not see how you can ride without one.
The effective seatpost length lost is about 95 mm if measured from the bottom-of-the-seatpost to the underside-of-the-saddle-rails. It is just long enough to fit like the original seatpost.

An alternative would have been to cut off 95 mm from the bottom, which would have saved 34 grams. With that background the weight saving is about 76 grams from switching out the clamping system.

10 mm setback hardware can be fitted if setback is an issue.
I hear ya, impressive work nonetheless!! :beerchug:

I did some work on mine last summer (Basso Palta)

Seatpost, from 215.8 to 182 (saved 33.8g) by removing paint (about 7g) and replacing the entire mounting thingy.

The frame clamp is the worst! Insanely heavy at 32.2g, I replaced the screw to titanium and drilled it out (only 3.5g) and saved a total of 9.3g after adding grease and tape to it.

Frame is heavy enough so I have given up on this project :D Basso is no WW :cry:

Would be great if it was possible to make an integrated clamp adapter and tuck it in the frame so you could use a normal 27.2 post
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Lucendi
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by Lucendi

eucalyptus wrote:
Thu Feb 03, 2022 9:44 pm
Would be great if it was possible to make an integrated clamp adapter and tuck it in the frame so you could use a normal 27.2 post
This is a thought I have had as well, it would be an elegant and inexpensive way to drop some serious weight.

The sleeve could be 3D-printed for prototyping and then CNC-machined out of aluminium for cheap.

However, I have not come across a proprietary aero/not-round seatpost that will fit a 27,2mm seatpost inside it's cross section.

naavt
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by naavt

I'm in the process of having the same kind of modification to a seatpost of mine, and the carbon specialist who's going to make it have shown me several examples like yours that have the carbon delaminated over time.

He went to explain me the whole process and why those mods have tendency to delaminate and put your health at risk. He also have shown me several seatposts from well known manufacturers who use the same design, and how internal structure and fibers are layed up to strenghten the most prone parts to delaminate.

The best designs (the ones that endure), have internal alu strengtheners where both clamp and rod goes. The issue is adhering alu to carbon perfectly and that's something that only a composits specialist can do properly.

I imagine that such an alu piece wont go over 10g, probably even bellow that, and that's weight that I'm happy to add just for my piece of mind.

I plan to share some pics once my seatpost is ready.

by Weenie


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F10
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by F10

I wonder if sealing with e.g. nail varnish or similar might help stop the water getting in and causing delamination...

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