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

Carbon Seatstay Crack

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.

Carbon Seatstay Crack

Old 10-02-19, 07:12 PM
  #1  
VtwinVince
Senior Member
Thread Starter
 
Join Date: Jul 2018
Posts: 126
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 26 Post(s)
Likes: 0
Liked 6 Times in 5 Posts
Carbon Seatstay Crack


After my ride today, I noticed a small crack in the carbon monostay of my Bianchi S9. I'm not sure if this is a manufacturing defect or a failure. Anyone seen anything like this? The stays are Reynolds, and the crack is about a quarter inch long, right at the top of the monostay.
VtwinVince is offline  
Old 10-02-19, 07:35 PM
  #2  
sch
Senior Member
 
Join Date: May 2003
Location: Mountain Brook. AL
Posts: 3,616
Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 201 Post(s)
Likes: 0
Liked 10 Times in 10 Posts
Looks more like a join between the smooth part of the CF tube and the 'dimpled' part of the CF.
Doubt a coin tap would help. Probably needs bike shop eval if the you are first owner and a
warranty is applicable, but you might lose use of bike for awhile if it is. Based on the pix,
I think it is nothing to be concerned about.
sch is offline  
Old 10-02-19, 07:56 PM
  #3  
Andrew R Stewart 
Senior Member
 
Andrew R Stewart's Avatar
 
Join Date: Feb 2012
Location: Rochester, NY
Posts: 12,146

Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Raleigh Pro, Trek Cycle Cross, Mongoose tomac ATB, GT Bravado ATB, JCP Folder

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1921 Post(s)
Liked 121 Times in 93 Posts
Was this bike bought by you through a shop? If so the I agree with having the shop (or other Bianchi dealer) examine the bike and have notes in their service system made. Even if they suggest it's no big deal you want the company to be on notice now. Do remember that most shops have no one with real carbon construction experience, sure there're lots of opinions but very few with true abilities. That isn't the point though. Getting documention now for any future ssue is.

I would also witness mark (love that term) the "crack's: ends best possible to further track development. Is there access to the mono stay's interion (vents, openings to other tubes)? If so then a penetrant could be introduced to the interion to see if it bleeds out via the "crack", Note that as a layered construct any crack might not be fully through the tube wall. Andy
__________________
AndrewRStewart
Andrew R Stewart is offline  
Old 10-02-19, 08:17 PM
  #4  
UKFan4Sure
Senior Member
 
Join Date: Jun 2015
Posts: 416
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 122 Post(s)
Liked 12 Times in 10 Posts
If you'll carefully notice, it looks like there is a section of more textured carbon that runs up to a smoother section. Both seem to intersect at that junction point that appears to be a "crack". I think it's just a point of where the carbon layers met, not really a crack. But if it were me, I'd still have it looked at by someone competent in making such evaluations.

My guess is it shouldn't be so scary. But hey, I've been wrong before. I am married, after all.
UKFan4Sure is offline  
Likes For UKFan4Sure:
Old 10-02-19, 08:54 PM
  #5  
hefeweizen
Senior Member
 
Join Date: Oct 2016
Posts: 99
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 30 Post(s)
Liked 9 Times in 5 Posts
What year is the frame?

Last edited by hefeweizen; 10-03-19 at 06:50 AM.
hefeweizen is online now  
Old 10-02-19, 09:17 PM
  #6  
AnkleWork
Senior Member
 
Join Date: Jan 2013
Location: Llano Estacado
Posts: 3,492

Bikes: old clunker

Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 598 Post(s)
Likes: 0
Liked 44 Times in 31 Posts
Riding season gets shorter every year.
AnkleWork is offline  
Old 10-03-19, 03:10 AM
  #7  
blamester
Blamester
 
Join Date: Dec 2011
Location: Ireland
Posts: 486

Bikes: Peugeot teamline

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 81 Post(s)
Likes: 0
Liked 8 Times in 7 Posts
What is the opposite side like?
Pull it back and forth and see doesn't open up.
Go from there.
blamester is online now  
Old 10-03-19, 10:17 AM
  #8  
VtwinVince
Senior Member
Thread Starter
 
Join Date: Jul 2018
Posts: 126
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 26 Post(s)
Likes: 0
Liked 6 Times in 5 Posts
Thanks for the feedback. Frame dates from 2005, and I did not buy it new. I did notice the difference in carbon texture right at the hairline. I will monitor the situation and see if it gets worse.
VtwinVince is offline  
Old 10-03-19, 10:52 AM
  #9  
TiHabanero
Senior Member
 
Join Date: Nov 2012
Posts: 2,636
Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 848 Post(s)
Liked 115 Times in 79 Posts
That is an odd place for a crack to develop, plus it does not follow the lug line, but is straight across the tube. As you said, monitor and inspect to see if it travels.
TiHabanero is offline  

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


Thread Tools
Search this Thread

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

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.