Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

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.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 02-15-10, 05:06 PM   #1
NateRod
Senior Member
Thread Starter
 
NateRod's Avatar
 
Join Date: Aug 2009
Location: Brooklyn, NY
Bikes:
Posts: 1,682
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Broken starnut?

I'm not an experienced bike mechanic, just a rider who does occasional minor work on his own bike, so I apologize in advance for this probably dumb question.

So, I was about to remove my stem today (threadless, 1.125"), to place it a little lower on the steer tube, below one of the spacers.

As I try to unscrew the top cap, I notice that the bolt head keeps turning and turning but won't go out. As I do this, I hear a scratching sound from within the steer tube. I turned it the other way and the same thing happens. The bolt just turns and turns. Doesn't come loose, doesn't tighten up.

is the starnut broken? I'm thinking I may have stripped it by tightening the bolt a bit too hard the last time I replaced my stem.

What are the dangers related to this? Could my stem pop off at some point, while I'm riding? I gave it a few sharp tugs upwards but nothing happened. Would I need a new headset? Could I just take it to a local shop and have them remove it somehow and replace it with a spare starnut?

halp!

Last edited by NateRod; 02-15-10 at 05:21 PM.
NateRod is offline   Reply With Quote
Old 02-15-10, 05:20 PM   #2
sooprvylyn
I suck, but you're worse
 
Join Date: Jun 2005
Location: LA
Bikes: Motobecane Fantom Uno-Got rid of the rest when I moved to LA:(
Posts: 672
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I assume you have a metal steer tube, either steel or alloy?

If your stem is properly adjusted then it doesnt matter if your compression cap is even on the bike. The only function of this cap is to set the tension on the headset, the stem has 2 bolts that hold it securely to the steer tube. you are in no danger of your stem coming off unless you have a carbon steertube(ie most carbon forks).

If you have a carbon steer tube I'd be concerned as you should not have a star nut in a carbon fork, you use a compression plug. A star nut will destroy a carbon steer tube.

Can you get the compression cap off of the fork at all? If not turn the bike upside down and take the front wheel off.
Next take a long metal rod(a long screwdriver or the like) and put it through the bottom of the steer tube until it contacts the star nut.
Use a hammer to tap the star nut(you may need some force) so that it goes higher up the steer tube, maybe only needs 1mm
hopefully if you can move it high enough it will bite and you can then unscrew it.


Always lube threaded parts before installing them, especially when they contact like metals(ie steel to steel), to prevent chemical bonding or rust from locking them up.
sooprvylyn is offline   Reply With Quote
Old 02-15-10, 05:24 PM   #3
operator
cab horn
 
Join Date: Jun 2004
Location: Toronto
Bikes: 1987 Bianchi Campione
Posts: 28,306
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
We just had this problem last week. All the relevant information is here:

http://www.bikeforums.net/showthread...p-cap-stripped
operator is offline   Reply With Quote
Old 02-15-10, 05:27 PM   #4
NateRod
Senior Member
Thread Starter
 
NateRod's Avatar
 
Join Date: Aug 2009
Location: Brooklyn, NY
Bikes:
Posts: 1,682
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
It's an alloy steer tube. I can't take the compression cap off at all, since it's held in place by that top bolt. It turns and turns but fails to loosen. Since I heard scratching inside the tube, I assumed that it's the starnut just spinning around, failing to create enough friction to "bite" and allow the bolt to spin independently.

I'll try your suggestion. Thanks!
NateRod is offline   Reply With Quote
Old 02-15-10, 05:30 PM   #5
NateRod
Senior Member
Thread Starter
 
NateRod's Avatar
 
Join Date: Aug 2009
Location: Brooklyn, NY
Bikes:
Posts: 1,682
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I wrote my previous post before operator's... I just took a look at this other thread. I'll give this a try...

and I'll make better use of the search next time.

Thanks!
NateRod is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

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



All times are GMT -6. The time now is 12:15 AM.