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Resizing seatpost from 24mm to 23.8mm

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Resizing seatpost from 24mm to 23.8mm

Old 10-21-17, 01:35 PM
  #1  
deadllama
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Resizing seatpost from 24mm to 23.8mm

Iím fixing up a Peugeot that came to me missing the seatpost. I thought it needed a 24mm aluminum post, but I bought one on eBay and it doesnít fit. I measured wrong (first time doing any of this) and I actually needed a 23.8 post.

I know itís possible to take .1mm off of the post, but I canít find specific recommendations for the best method... who has done this before and how did you do it?
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Old 10-21-17, 01:55 PM
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First time I’ve heard of that size on a Peugeot. Does the seat post have an insert?
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Old 10-21-17, 02:27 PM
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Peugeot Versaille ? rare.

the only way to correctly reduce an aluminum seat post .008" is to turn it with a lathe.

considering it's an old steel frame, i'd think more towards increasing the seat tube ID of the frame.... or trying to find a 23.8mm post.

or you can spend a couple/three hours, and use several pieces of sandpaper, and expose yourself to dust that is known to cause alzheimer's... and acute aluminum poisoning causes severe flu-like symptoms, including extreme dehydration, and possible death from extreme fever... been there... two weeks of living hell...

Al = Aluminum - a Toxic Element - Linked to many diseases in humans
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Old 10-21-17, 02:50 PM
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24 - 23.8 = 0.2mm, so you need to be be taking off 0.1mm of wall thickness

you can also ream out the bore of the seat tube with a 25mm reamer or drill bit in the drill press

1" is just a bit bigger at 25.4mm.. Kalloy makes 25* & lots make 1" seatposts..

*Campag makes 25mm seat posts too, My AlAn bikes used a 25mm seat post .. but I doubt you want to spend that much..




.....

Last edited by fietsbob; 10-21-17 at 03:49 PM.
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Old 10-21-17, 02:55 PM
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Originally Posted by fietsbob View Post
24 - 23.8 = 0.02mm, so you need to be be taking off 0.01mm of wall thickness.
Nope. 0.2mm, take off 0.1mm.
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Old 10-21-17, 02:58 PM
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This is not a link I would give much credence to. Go to the top of the site to see what I mean.

The Tortoise Shell Life Science Puzzle Box - Understanding the Puzzle of Life
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Old 10-21-17, 03:15 PM
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Originally Posted by Aubergine View Post
First time Iíve heard of that size on a Peugeot. Does the seat post have an insert?
Itís a PH10LE. I think the Versailles is the same basic model, from after they started giving them names instead of letters and numbers.

I was expecting it to be 24mm but it just doesnít fit. Goes in about 5mm and stops. Thereís no insert, the post is just ever so slightly too big.

Last edited by deadllama; 10-21-17 at 03:21 PM.
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Old 10-21-17, 03:45 PM
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Originally Posted by Aubergine View Post
This is not a link I would give much credence to. Go to the top of the site to see what I mean.

The Tortoise Shell Life Science Puzzle Box - Understanding the Puzzle of Life
do some basic research on Aluminum poisoning, and aluminum's link to alzheimer's disease... you'll find two things... the government has teamed with industrial makers of aluminum cookware to attempt to remove any and all studies pointing out the direct links between aluminum and alzheimer's, and the few studies not wiped from the internet showing the link... the carefully worded report on the studies, dated 2008, is particularly interesting... the report goes out of it's way to dodge the actual effects by talking about all the non-effects at length.... the report was paid for and compiled by... THE ALUMINUM INDUSTRY.... from info they provided.... much like Monsanto's reports on the chemical compound Roundup.... they chose to look only at Glyphosate, and ignore the Tallow Amine completely...

as to aluminum poisoning,. it's quite real... screaming ****s, deadly body temps, uncontrolled vomiting... etc... like i said... been there... 105+ temp for a week straight... and went through a twelve pack of TP by myself... etc. Great way to lose 35 lbs. in a hurry! it took a month before i felt "normal" again...
there is no aluminum cookware in my house now.... i wear gloves and a mask when sanding aluminum.

Last edited by maddog34; 10-21-17 at 03:51 PM.
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Old 10-21-17, 03:51 PM
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So Reagan did what he did because of aluminum cookware?
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Old 10-21-17, 05:04 PM
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Originally Posted by deadllama View Post
Itís a PH10LE. I think the Versailles is the same basic model, from after they started giving them names instead of letters and numbers.

I was expecting it to be 24mm but it just doesnít fit. Goes in about 5mm and stops. Thereís no insert, the post is just ever so slightly too big.
Slap some valve lapping, carborundum loaded grease, compound on it and grind it in

.
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Old 10-21-17, 06:20 PM
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How hard/expensive is it to buy the right sized seat post?

There might be some answers in this thread from 2010 where someone faced the same problem
23.8mm Seatpost Dilemma
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Old 10-21-17, 07:24 PM
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...an aluminum alloy seat post is easily taken down the amount you require by simply wrapping some medium grit abrasive paper or cloth around it and going at the section you need to insert by twisting the post in the paper held in your hand. Try to get it even up and down the length you require for insertion by moving it up and down a little as you rotate it. Or if you have a way to hold it in a vise without scarring it, you can just use strips of abrasive to work on it like a shoe shine cloth, being careful to attend to the entire circumference, not just the top side.

I've done this five or six times myself, and I know it works out fine if you pay attention, and stop to fit the post in the tube periodically to make certain you're not taking off too much. Aluminum is probably not a good thing to ingest or other wise take internally, so you might want to wear a dust mask. It's certainly not the most toxic stuff mechanics encounter regularly.

Make certain you have shortened the post to your required depth of insertion for your particular saddle height. Most of them come pretty long from the manufacturer these days. Maybe leave a few extra inches for whanever someone else ends up with the bike, so they don't have to do the whole thing over again.
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Old 10-21-17, 07:59 PM
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Originally Posted by maddog34 View Post
do some basic research on Aluminum poisoning, and aluminum's link to alzheimer's disease... you'll find two things... the government has teamed with industrial makers of aluminum cookware to attempt to remove any and all studies pointing out the direct links between aluminum and alzheimer's, and the few studies not wiped from the internet showing the link... the carefully worded report on the studies, dated 2008, is particularly interesting... the report goes out of it's way to dodge the actual effects by talking about all the non-effects at length.... the report was paid for and compiled by... THE ALUMINUM INDUSTRY.... from info they provided.... much like Monsanto's reports on the chemical compound Roundup.... they chose to look only at Glyphosate, and ignore the Tallow Amine completely...

as to aluminum poisoning,. it's quite real... screaming ****s, deadly body temps, uncontrolled vomiting... etc... like i said... been there... 105+ temp for a week straight... and went through a twelve pack of TP by myself... etc. Great way to lose 35 lbs. in a hurry! it took a month before i felt "normal" again...
there is no aluminum cookware in my house now.... i wear gloves and a mask when sanding aluminum.
Don't forget you can also buy Aluminum as a FOOD ADDITIVE.

Look at your typical baking powder. Sodium aluminum phosphate.

I used to like Totino's Pizza until I discovered it used aluminum baking powder.
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Old 10-22-17, 07:13 AM
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I did this on a carbon post. Just sand it a bit. Then polish. Since it's aluminum, maybe toss it in an anodizing bath after.
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Old 10-22-17, 07:22 AM
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Originally Posted by maddog34 View Post
....i wear gloves and a mask when sanding aluminum.
That makes sense no matter what you are sanding. No metal or wood dust is particularly good for you.

As to that Aluminum/Alzheimer link, that has been very discredited and your conspiracy theory that the government and aluminum producers conspired to hide it strains credulity. I don't know for sure what caused your symptoms but if it was "aluminum poisoning" you mast have been exposed to huge amounts of fine Al dust for a protracted period.
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Old 10-22-17, 02:32 PM
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I had a similar problem with my Peugeot PX10. I had a gorgeous Cineli stem that I wanted to use, but it would fit. Its been about 30 years since I did this, but I think the Cinelli stem was 22.2 mm, and the Peugeot need a 22 mm.

I had access to a good lathe with a 4 jaw chuck and after very careful setup, I was able to take off .2 mm. It worked fine for probably 20 more years.

However, just because it can be done, doesn't mean you should. Some of the other suggestions make a lot more sense to me. Reaming out the seat tube would be a lot easier, requiring less equipment and probably a lot less skill. But best yet would be to search out the right size post to begin with.
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Old 10-23-17, 02:56 AM
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Originally Posted by joeruge View Post
It worked fine for probably 20 more years.
Only 20 years? So it was a temporary fix then
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Old 10-23-17, 11:39 AM
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... I said 20 years only because I stoped riding that bike about 10 years ago. Though actually, now that you mention it, I'm sure it is still working fine, though only hanging in the garage!
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