Broken Stem/Handlebar Attachment?

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navifty

New Member
Oct 22, 2011
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Finishing up a build using a Micargi frame/stem. The handlebars had way too much play side-to-side in them, and when I went to tighten their mount, something popped and now they're totally free and slide right off. It looks like the bolt that keeps them tight is supposed to go from the top down to a nut held in place below some star-shaped thing, but I'm not sure how to fix it. Anyone have any idea? Pics below for reference.
 

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GearNut

Active Member
Aug 19, 2009
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I am not really familiar with that setup, but it looks like the nut was part of a spring steel insert that is pressed into the fork stem and the nut broke off of the insert.
Perhaps you can get another insert or if the stem is hollow and open on the bottom you can reach up inside it with a ratchet and extension and, using a washer as a backup for the now too big of a hole in the insert, fit a nut onto the bolt from underneath?
FWIW the pinch bolt going through the side of the handlebar clamp it what tightens up the handlebar clamp to the fork stem and that should take care of any excessive wobble IF the clamp is actually the correct size for the fork stem. If the clamp hole is much larger than the fork stem it needs to be replaced with the correct sized one as you will never get the clamp to close up enough.
The top bolt you were tightening is only there to hold the parts together when shimming up the fork stem bearings for proper bearing free play, hence the low load bearing insert. The handlebar clamp is what holds everything in place when all is set up done.
 

navifty

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Oct 22, 2011
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Thanks gearnut. Apparently the clamp that came with this setup is not the right size, because it's doing nothing to hold the handlebars in place.
 

navifty

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Oct 22, 2011
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Yep, I tightened those down as much as humanly possible and still had crazy play. I ended up wrapping the stem in electrical tape and then tightening down as much as I could, and it's pretty decent now.
 

GearNut

Active Member
Aug 19, 2009
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Just be veeeerrry careful with that!
You are now relying on the strength of electrical tape to provide yourself with the ability to maintain balance and control of your MB.
If you ever find yourself in let's say a turn, and there is a rock , bump, pot hole, or whatever, that catches the front wheel, can you maintain proper control if the electrical tape slips and the front wheel does not go where you turn it to go when you readjust for balance or direction?
Just sayin' man, that sounds pretty sketchy to me!
 

ocho ninja

Member
Jan 14, 2012
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San Jose, CA
Maybe you have a 1" threaless steerer tube that needs a 1" stem
And what u have is a 1" and 1/8
Or
Maybe the stem is not going over enough of the steerer tube and barely catching the allowing for some play.
 
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thegnu

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Sep 15, 2011
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uschoppers has a shim you can use there , just be sure to rough up the shim inside an out as well as the steer tube an inside of the handle bar mount, I had a similar problem with mine , as far as the cover is concerned drive the peice of spring steel deeper into the steer tube or completely out if you can an someplace like lowes may have a suitable replacement its only a wellnut
 

2door

Moderator
Staff member
Sep 15, 2008
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Would you rely on tape to keep the steering wheel tight on your car? Same thing. You're playing on thin ice, sir. If you're in doubt about the repair take the bike to a local bike shop and get it done right. Steering controls are nothing to scrimp on.
Tom
 

timboellner

Member
Apr 1, 2009
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Towson Maryland
Navifty,
You have broken the star nut.

The bolt you were tightening sets the pre-load on the upper and lower bearings in the front fork assembly. It only tightens and loosen the bearings.

In order to tighten or loosen the bearings you should have loosened the 2
pinch bolts prior to cranking on that nut. The tight pinch bolts prevented the bolt you turned from doing it's job. You ripped the star nut right out of the steerer tube.

Here's a link to get a new star nut and bolt. The Problem solvers is probably the one for you. You will need to know if you have a 1" or 1 1/8" steerer tube to get the correct one.

http://www.niagaracycle.com/advanced_search_result.php?keywords=star+nut&x=0&y=0


I suggest you do some homework before you screw something else up or get hurt Mickey Mousing your repairs.

The Sheldon Brown website is a great place to learn. Here's a link to learning about Star nuts and such. I'd hate see your nuts see stars .

http://www.sheldonbrown.com/headsets.html

Go down the page till you get to adjusting threadless headsets.


Good luck and be safe

TiM
 

rustycase

Gutter Rider
May 26, 2011
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Timbo and GN got it right...

and don't use tape! lol
any aluminum beverage can could have been cut into strips with a scissors for a better quality shim than tape! :)

You may need to just kinda fake the preload on the fork bearings now... replacing the stripped piece might be on the pricey side...

Good luck
rc
 

The_Aleman

Active Member
Jul 31, 2008
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el People's Republik de Kalifornistan
The star nut can be replaced easily. It's not a big deal. What is a big deal is that OP needs to shim anything. He shouldn't have to.

Obviously has a mismatch of something there. I'm thinking 1 1/8 stem on a 1" fork. Less common, a 1 1/4" stem on a 1 1/8" fork.