French Seatpost Slippage
04-25-20, 03:59 PM
#1
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French Seatpost Slippage
I am currently using a 25.8 seatpost that was squeaking. I applied grease went for a 60 mile ride and found it slipped down almost 2cm. To be fair, the seatpost clamp when tight has no gap. I never had slippage when I had it in dry. I have read about the inconsistency of vintage French bikes regarding seatposts, but curious if any of you have personally fixed this by:
Find a 26.0 seatpost?
How much bigger of a seatpost is likely to fit?
Get a bigger seatpost and lightly sand until it is just right?
Carbon paste?
Anti-seize?
Find a 26.0 seatpost?
How much bigger of a seatpost is likely to fit?
Get a bigger seatpost and lightly sand until it is just right?
Carbon paste?
Anti-seize?
04-25-20, 04:04 PM
#2
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Is this for your '81 PKN 10? That seatpost size doesn't seem right for that bike.
04-25-20, 04:06 PM
#3
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I am currently using a 25.8 seatpost that was squeaking. I applied grease went for a 60 mile ride and found it slipped down almost 2cm. To be fair, the seatpost clamp when tight has no gap. I never had slippage when I had it in dry. I have read about the inconsistency of vintage French bikes regarding seatposts, but curious if any of you have personally fixed this by:
Find a 26.0 seatpost?
How much bigger of a seatpost is likely to fit?
Get a bigger seatpost and lightly sand until it is just right?
Carbon paste?
Anti-seize?
Find a 26.0 seatpost?
How much bigger of a seatpost is likely to fit?
Get a bigger seatpost and lightly sand until it is just right?
Carbon paste?
Anti-seize?
Google is your friend.
04-25-20, 04:06 PM
#4
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It is actually for the St. Etienne that I suspect is a straight gauge French 531. I am curious if there is a preferred gap in the seatpost pinch.
04-25-20, 04:11 PM
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For an ideally sized post, the gap at the top of the cinch slot should only be ~0.6mm narrower than the width of the cinch slot at the bottom.
04-25-20, 05:27 PM
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Revracer -
The 25.8 mm seatposts were what came on PG Carbolite hi-tensile frames on Peugeots like the PB 12 Course. Usually PG 531 was about 26.8 ish. The seatpost definitely seems under sized.
The 25.8 mm seatposts were what came on PG Carbolite hi-tensile frames on Peugeots like the PB 12 Course. Usually PG 531 was about 26.8 ish. The seatpost definitely seems under sized.
04-25-20, 06:19 PM
#7
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Post a pic of the collar/lug. Can you file a quick solution? Sanding down a larger seatpost is a lot easier when the bike is a keeper. You know exactly how much of the post to file for your riding position. Pretty easy.
04-25-20, 08:00 PM
#8
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...this is what I do, mostly. Make sure you expand the top where the slot has been squeezed down before you fit the new post.
I try for a fit where there's some resistance when I slide the post in and down into the un-slotted portion of the seat tube.
Also, file off any burrs on the interior at the top, because those can confuse you on fit.
I try for a fit where there's some resistance when I slide the post in and down into the un-slotted portion of the seat tube.
Also, file off any burrs on the interior at the top, because those can confuse you on fit.
