mr9iron

Hi all, need some help or suggestions here...

I am restoring a vintage Peugeot Super Vitus 980 bike frame. I encountered something that I never saw before when I disassembled the bike. This bikes used a quill seat post. The only reason I figured this out was from a post I saw here on the forum when researching this item. I knew something was up when I neglected to notice a seat bolt present.

So all and good I removed it, it is in rough shape but still works, and I can get it to look decent with some effort, so what's the problem? Here is what I have issue with, it is sort of a "weight weenie" issue, this Vitus frame is amazingly light, and this seat post weighs a ghastly 375 grams, nearly 3/4 of a pound! I was hoping to replace this counterweight with something more respectable, something more worthy of this light frame.

The long Allen screw you see pictured in the attachment, alone weighs around 100 grams. It is an M5 metric bolt, but I cannot even find a lighter alternative as the longest bolt you can find is maybe 30mm in length this one is nearly 285mm in length.. So no luck there.. Post says, "Made in France," must be a French thing, but they should be ashamed at making such a heavy post on a frame that is sub 4lbs.. I don't get it, the Vitus frame tubing is French, why kill all your hard effort in making a killer frame with a horribly heavy seat post, negating all your gains on the frame..

A suggestion put forth on an older post, is to cut a relief in the seat tube of the frame and use a seat clamp. This is not an option for me as the frame is lugged and there is no cylindrical area to clamp, plus I would hate to cut this otherwise original frame.. I see a Campagnolo quill seat post on ebay for over $300!!!, what did I do, break a window?-that is just ridiculous I paid $150 for the entire bike, plus I do not know if it is any lighter, they don't list the weight.

Any alternatives? Could a standard, lighter seat post be converted to a quill post? Any ideas or thoughts appreciated.

fietsbob

you know someone with a Lathe , a Machine shop? what tools can you use and find, to execute your plan?

Look at HB stems there are conic type expanders the post itself spreads its machined conically inside , and wedge type..
perhaps just sawing the end off att an angle, then welding a nut across the open end, cut off, will do .

NB: The parts for a 9/8" threaded forks include a wedge that is 1" OD, regular 7/8"

Id probably make my 1st attempt with a straight stepped tube seatpost so you dont have to remachine a built in head , post.. with a hole thru it ..

whats wrong with the one you pictured ?

Anything you do wont be free in cost.

You can also hire a Nut Brazed on the back of the seat tube on the frame and fix the seat post height, with a setscrew.

then use a common post , but it cannot be too thin. probably no less weight than the one in the picture. (except no bolt down the middle. )

or another Idea , get someone to make a quill bolt in 7075t6 aluminum or Titanium

or fabricate one that is mostly a hollow Chromoly steel tube with the threading and head brazed on.

cny-bikeman

Even if you were to convert a conventional post, adding the quill mechanism and the requirement of a long bolt will not save much weight at all, the Campy saves 3.5 oz, and converting the frame to a standard post would be very expensive when you add in a paint job. But for argument's sake let's say you could magically have a standard post. A reasonable weight without going to expensive and questionable extremes is about 200 grams (see the options at Weight Weenies - Seatposts). That is a 150 gram difference, or about 5 oz. I think there are better things to do with your time and money - like riding.

Andrew R Stewart 

I would be very careful when making one's own seat post to fit this bike. If you look carefully at the OEM post you'll see that the expanding band (NOT a wedge) has it's slot cut on a spiral. This is so that the contact/pressure points against the seat tube's ID is spread out over a large area. to have the small and highly focused pressure points of a wedged clamp (like a bar stem has) will likely distort the seat tube. Just check out the wall thickness of a fork's steerer VS the seat tube's. Major difference!

This is the cost of having a bike which has a unique design. Suck it up and just ride the bike. Or get a different bike which is compatible with a greater range of components. Andy.

HillRider

I expect Vitus was leery of welding seat post clamp bolt tabs to their aluminum frame for fear they would break off under adequate torque. Also, this frame was made before seat post clamp collars were available so they did the safest thing. Remember, this was a very early, light, small diameter, thin wall aluminum frame made before stronger alloys were commonly used.

fietsbob

You must mean another Frame.. Vitus being a steel tube maker, Primarily .

That one looks like Steel to me... brazed lug and brazed on seat stays.
by the color, inside of the seat tube Oxidization/Rust.. so missing the mark .. nice guess.

it was done for steel frames too, just for aesthetics..


get out the magnet and test it.


Bet this one is steel too https://i46.tinypic.com/s2hemf.jpg

the aluminum epoxied together ones were not painted, tubes anodized and colored before assembly..

they were putting a set screw into a rather small seat post because the small tubing was rather thick wall

I Owned their Italian competitor the post was 25.0.. FD was standard 28.6 band so seat tube, a 1.8mm tube wall .

have a recollection that there was a 23mm seat post in some french bikes , maybe the aluminum ones .

well biked

Peugeot and Schwinn (early aluminum frames) were two major brands that used quill seatposts during that era. When we see one in our shop, we usually give a collective groan. They're problematic. If you've got one that's working, regardless of its weight, count yourself lucky.

Wilfred Laurier

If this bike had been made in the past five or ten years that you have a reason to be annoyed at the lack of aftermarket compatibility, but on a 35 or 40 year old bike you need to expect to spend effort or money to get an upgrade. If what you really wanted was a super lightweight performance oriented bike, and not a museum piece, then you bought the wrong bike.

Grand Bois

Super Vitus 980 is steel.

HillRider

Yep, I missed it. The Vitus 980 is indeed a steel frame. I was apparently thinking of the Vitus 979 which was a lugged and bonded aluminum frame.

fietsbob

Glad To help some one in Pittsburgh, PA .. where Steel is Made .. They do still make steel there don't they?



actually the tubes fit over the liner sleeve pieces HP cast into part of the seat cluster piece, Head tube, and BB..

The AlAn Looked Lugged because the same parts were threaded inside and the threaded tube ends were rotated ,
turnbuckle like, to pull them onto the tubes from both ends at once..

Screwed and Glued as they got called ..

mconlonx

Bask in the C&V glow of polished obsolete and proprietary parts.

Reynolds 

There were some F. Moser frames that used a quill seatpost too IIRC.

cycle_maven

Gawd. I'd just be glad that:

a) It came with the bike, cause finding another compatible one would be a nightmare
b) It wasn't stuck in the seat tube.

noglider 

Yeah, really. You have the perfect seatpost for your bike. Use it. Don't complain.

HillRider

Not much anymore. Most of the big mills are gone and only a very few major and some specialty mills remain. It's not the same city by any means


That's the way the bonded Treks of the late '80's and early'90's were made. They were quite durable and I still have a '92 1420 my son uses as a commuter every week.

mr9iron

Wow, intense replies, thank you to everyone who replied to my inquiry. Just to answer some of the questions that came up.. This is the bike I wanted to restore, simply because these were the "unattainable" bikes when I was young. The 980 Super Vitus as already mentioned here, is very light steel, even by today's modern steel standards, is still quite light. I have another ride that is my everyday bike, so this one is just going to be for fun rides.

I had no idea they used this seat post as the model before and after are standard, I just never noticed this.

Seems like the best option is to stick with it, the threads on the long draw bolt are in rough shape and are very tight, does anyone know where I can get a replacement this long? It is an M5 .8 thread (standard M5 metric bolt)

Thanks in advance..

J

fietsbob

the 5x.8 threading die can be found easily to clean up the threads on the existing one, ditto the Tap

as I said .. Custom .. whether you are in Puyallup Washington state, or Perth Western Australia

re machine a QR skewer, or hire a custom one made . with the flat head.

Kimmo

I'd be tempted to get a carbon post in a larger size and have it turned down to be a stiff fit, and carve the lip to fit the lug exactly.

jyl

I might try getting a die and threading some aluminum rod to replace the long steel bolt, using a nut on the upper end. Also get a tap and some larger diameter aluminum rod and make a replacement for the conical expander. I suspect the torque on the seatpost bolt is not high, so that the aluminum could work, and failure won't cause a crash. Also get a Ti bolt for the seat rail clamp. All that might save you 100 grams, guessing. After that, I don't see how you can lighten the post without milling or drilling - and I'd be very loath to make any permanent changes to the seatpost, since if you break it, you're screwed.

If you want to get more creative, perhaps the spiral expander can be used on a different, lighter seatpost if you shape the end of the post appropriately. Maybe even a carbon post.

Looigi

Don't know if it's been suggest yet or not, but you could turn it into a ISP by brazing a tube into the seat tube. Another possibility would be epoxying in a seat post. There are certainly issues with either approach, but something to consider...

fietsbob

As usual, the way you make things Lighter is with applications of more Money.

Grand Bois

I have made quill posts for a couple of Peugeot owners and for my own Kabuki Submariner. I use a Laprade post, an aluminum wedge from a 1 1/8" stem and a very long stem bolt available from Nitto. It probably isn't any lighter than the post you have and I can't guarantee that the wedge wouldn't bulge the seat tube. It's better than nothing if the original quill post is broken or missing. They're nearly impossible to find.