Vitus 25mm expanding seatpost

ChiefCrowLeg · Jun 7, 2013

I've been on the lookout for an expanding seatpost for my Vitus Dural 979. The previous seatpost sheared clean through & I stupidly binned it, thinking it would be easy to replace. This seatpost has an allan key bolt running from the top where the seat is secured, right down the middle of the seatpost. When tightened it draws a wedge up inside the seatpost, expanding the seatpost out against the bike frame tube. They are impossible to find. Anybody know where I could buy one?

one_bad_mofo · Jun 7, 2013

I know just the sort of thing you mean, my old Vitus had the same set-up. The only advice I can offer is to try cycle jumbles. When I went to the Herne Hill Good Friday meet there was all many of strange old stuff available from various traders.

Midlife · Jun 7, 2013

Peugeot and Moser used a similar system, not sure about trhe size though. Might be worth including those names in any searches?

Shaun

torqueless · Jun 8, 2013

I think there was a Sun-tour post with that feature.

Citoyen du monde · Jun 8, 2013

You can actually make your own if you so wish.

legrandefromage · Jun 8, 2013

Citoyen du monde":g8z8g0pr said:
You can actually make your own if you so wish.

what he said

Midlife · Jun 8, 2013

You mean use a stem bolt and drill through the top of a normal seat post?

shaun

legrandefromage · Jun 8, 2013

a 25.4mm wedge would need machining down but I cant see a problem. match the angle of the wedge to the post and off you go. its no different to fitting a quill stem at the front.

Theoldfm · Jun 9, 2013

ChiefCrowLeg":2qkmut5m said:
I've been on the lookout for an expanding seatpost for my Vitus Dural 979. The previous seatpost sheared clean through & I stupidly binned it, thinking it would be easy to replace. This seatpost has an allan key bolt running from the top where the seat is secured, right down the middle of the seatpost. When tightened it draws a wedge up inside the seatpost, expanding the seatpost out against the bike frame tube. They are impossible to find. Anybody know where I could buy one?

Is that the only type of seat post you can use?

On my Vitus there is a grub screw on the frame casting that tightens into the seat post to hold it in place. As mine is a Cyclo cross frame I have also supplemented this with a clamp type fitted around the post itself which stops it dropping down.

Citoyen du monde · Jun 10, 2013

legrandefromage":1x30m3w8 said:
a 25.4mm wedge would need machining down but I cant see a problem. match the angle of the wedge to the post and off you go. its no different to fitting a quill stem at the front.

This is basically what I have done in the past. You do however need to be careful that you do not cause expansion of the seat tube. A quill stem exerts much less stress on the steer tube than does a seatpillar on a much weaker (generally thinner gauge) seat tube. So do be careful but it does work. Theoldfm's suggestion is another way of doing it.

Vitus 25mm expanding seatpost

ChiefCrowLeg

Retro Newbie

one_bad_mofo

Old School Hero

Midlife

Retro Wizard

torqueless

Senior Retro Guru

Citoyen du monde

legrandefromage

Midlife

Retro Wizard

legrandefromage

Theoldfm

Citoyen du monde

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