Go Back  Bike Forums > Bike Forums > Bicycle Mechanics
Reload this Page >

Problem with Uno Long Seatposts

Notices
Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

Problem with Uno Long Seatposts

Old 06-26-15, 07:18 PM
  #1  
Senior Member
Thread Starter
 
Join Date: Dec 2012
Location: Okefenokee Swamps.
Posts: 576

Bikes: Rockhopper, Azor Oma cruiser

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Problem with Uno Long Seatposts

Plural. I replaced the originals in both my 1992 RockHopper and brand new Azor. With the seatpost bolt sufficiently tightened on both bikes, both seatposts manage to sink down into the seat tube approx a millimeter or two after a half an hour ride and I'm seriously considering a replacement as I've never experienced this problem with a seatpost until now. And the original seatposts never gave me any problem other than being either a bit short or with not enough setback.

I think that these Unos were undercut a tiny bit on the lathe.

Last edited by tjkoko; 06-26-15 at 07:26 PM. Reason: Clarity
tjkoko is offline  
Old 06-26-15, 09:42 PM
  #2  
Full Member
 
Join Date: Apr 2014
Location: Central Oregon
Posts: 457

Bikes: Redline Conquest Pro, Kona Cinder Cone, Trek Fuel EX8(RIP) Pivot Mach 5 frankenbike

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 15 Post(s)
Liked 10 Times in 9 Posts
Can you get a caliper or micrometer and measure the post's diameter? I have had an undersized post from Sette (Pricepoint) before, and nothing would clamp it down. For just slightly loose you could try carbon paste, since the abrasive beads will reduce slippage.
SlowJoeCrow is offline  
Old 06-27-15, 02:54 AM
  #3  
Senior Member
Thread Starter
 
Join Date: Dec 2012
Location: Okefenokee Swamps.
Posts: 576

Bikes: Rockhopper, Azor Oma cruiser

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Originally Posted by SlowJoeCrow
Can you get a caliper or micrometer and measure the post's diameter? I have had an undersized post from Sette (Pricepoint) before, and nothing would clamp it down. For just slightly loose you could try carbon paste, since the abrasive beads will reduce slippage.
29.2 mm is what the post measures just like the original one. I ended up getting some FSA Carbon Seatpost Assembly Gel. If that stuff fails then I'll try some from Park Tools with larger beads.

In the meantime I'll remove the grease from the seatpost and the inside of the seatpost clamp and see what happens.

Last edited by tjkoko; 06-27-15 at 03:05 AM. Reason: Addt'l info.
tjkoko is offline  
Old 06-27-15, 06:33 AM
  #4  
Old fart
 
JohnDThompson's Avatar
 
Join Date: Nov 2004
Location: Appleton WI
Posts: 24,878

Bikes: Several, mostly not name brands.

Mentioned: 153 Post(s)
Tagged: 0 Thread(s)
Quoted: 3548 Post(s)
Liked 3,295 Times in 1,886 Posts
What does the slot on the seat tube look like when clamped? Are the sides parallel? Do they touch? If so, the post is under size.

What kind of clamp are you using on the seat tube? If a quick-release clamp, try changing to a regular bolt instead to allow tighter clamping.
JohnDThompson is offline  
Old 06-27-15, 05:06 PM
  #5  
Senior Member
Thread Starter
 
Join Date: Dec 2012
Location: Okefenokee Swamps.
Posts: 576

Bikes: Rockhopper, Azor Oma cruiser

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Originally Posted by JohnDThompson
What does the slot on the seat tube look like when clamped? Are the sides parallel? Do they touch? If so, the post is under size.

What kind of clamp are you using on the seat tube? If a quick-release clamp, try changing to a regular bolt instead to allow tighter clamping.
The sides are parallel and not touching; and, a bolt, not quick-release, is being used to secure the seat post. My immediate plan is to remove the grease from the contact areas of both the clamping area inside of the seat tube and the seat post to see if it solves the problem.

The original seatpost shows lathe tooling marks (all uniform) along the exterior of the original seat post whereas the the Uno seat post appears almost smoothened to a mirror finish. So it appears that the fine ridges of the former may serve to "grip" the wall of the seat clamp.

Last edited by tjkoko; 06-27-15 at 07:34 PM. Reason: Clarity
tjkoko is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
mattkime
Bicycle Mechanics
5
03-29-18 08:13 PM
kkey1066
Bicycle Mechanics
9
10-09-17 09:06 AM
Odin99
Classic & Vintage
6
08-04-14 07:15 PM
kafong
Bicycle Mechanics
2
08-22-11 05:28 PM
JimOfOakCreek
Bicycle Mechanics
7
05-25-10 06:24 PM

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.