Broken Stem Bolt

[yodelinpol]

Anyone ever break a quill stem wedge bolt?

I was changing out my Nitto Pearl to a technomic Nitto with a slightly shorter reach. I greased the stem itself just a little. For some reason I could not get the wedge bolt to tighten enough to keep the stem from turning under any kind of normal force from left to right on the bars/stem. I kept tightening and SNAP! ***? Had to take the front wheel off and poke the wedge out from the under side of the head tube. The bolt had snapped about a half to a full cm above the wedge on the stem side.

Weird thing is that I've had this stem on there before and no problems. But i'm not sure what height it was at when i had it on there before. It does go much further down (longer) into the head tube/steerer tube than the Pearl does. I put the Pearl back on and no problems with it.

Any thoughts? I'm trying to decide whether to get a new bolt (and maybe wedge) and try again or maybe just getting a Pearl with the reach I need that doesn't go as far down into the steerer tube as the technomic.

Edit. FYI: This is a 60 cm Atlanta and stock steel fork.

Could the play in the stem/steerer tube be due to corrsosion in the steerer tube or excessive grease and dirt build up at the point in the tube where the wedge was trying to expand and hold? Or maybe too deep and too close to the bottom of the tube? Any theories? Like I said the pearl with a higher point of wedge contact in the steerer tube works great.

[yodelinpol]

Anyone ever break a quill stem wedge bolt?

I was changing out my Nitto Pearl to a technomic Nitto with a slightly shorter reach. I greased the stem itself just a little. For some reason I could not get the wedge bolt to tighten enough to keep the stem from turning under any kind of normal force from left to right on the bars/stem. I kept tightening and SNAP! ***? Had to take the front wheel off and poke the wedge out from the under side of the head tube. The bolt had snapped about a half to a full cm above the wedge on the stem side.

Weird thing is that I've had this stem on there before and no problems. But i'm not sure what height it was at when i had it on there before. It does go much further down (longer) into the head tube/steerer tube than the Pearl does. I put the Pearl back on and no problems with it.

Any thoughts? I'm trying to decide whether to get a new bolt (and maybe wedge) and try again or maybe just getting a Pearl with the reach I need that doesn't go as far down into the steerer tube as the technomic.

Edit. FYI: This is a 60 cm Atlanta and stock steel fork.

Could the play in the stem/steerer tube be due to corrsosion in the steerer tube or excessive grease and dirt build up at the point in the tube where the wedge was trying to expand and hold? Or maybe too deep and too close to the bottom of the tube and thus not being able to grip the butted section of the steerer? Any theories? Like I said the pearl with a higher point of wedge contact in the steerer tube works great.

bump for bordom and curiousity... anyone? Any wrenches out there?

[katematt]

The wedge wasn't lined up. Would be hard to do, but it's a long shot, and would depend on how loose it was when you thought it was tight.

Just a thought, since I can see corosion causing that much open space.

[RPS]

For some reason I could not get the wedge bolt to tighten enough to keep the stem from turning under any kind of normal force from left to right on the bars/stem. I kept tightening and SNAP!How hard did you try to turn the bars? And how tight did you torque the bolt before you tried turning the bars? I ask only because I can visualize how the bolt could become stressed by twisting hard on the bars, which could lead to subsequent failure when you tightened more.

Since you had used the stem before, I'd also check the surfaces of the quill and wedge to make sure they are in good shape and don't have a defect that could prevent free movement.

[David Kirk]

You may have two or more things working together here -

1) the steerer maybe be stretched from over tightening the wedge bolt on the past. If you over tighten (frankly hard to do if you have any kind of "touch") it will make the steerer swell like a snake that ate a rodent. Once it stretched the fork is toast as you'll never get a stem to stay tight and the fork steerer is compromised. If you pull the fork and lay the steerer on a flat surface it will be obvious if the snake has eaten a large rodent.

2) the stem wedge angle and the stems wedge angle may not match. This happens when folks assume that the angle is standardized and combine parts from various stems.

3) you stem bolt was just plain fatigued. Think of the stress they are under 24/7 when they are tight. For years at a time they sit there being stretched and eventually they will fail. This is especially true with older Cinelli type stems with a long skinny bolt. "Modern" quill stems all came with short and fat bolts. This lessened bolt wind-up when being tightened.

4) the threads on the bolt may be way past their prime of may be dry which will put a huge twisting load on the bolt while NOT pulling the wedge up.


FWIW that final turn of the bolt when you thought you were tightening the bolt was really the bolt being twisted and breaking.

Does this help?

dave

[TimD]

It doesn't seem like this happens very often - fortunately. Suggest two things:

Inspect the failed bolt for signs of corrosion.

That you source a new stem bolt, install it, and ride on :)

[Richard]

Just for safety's sake, you should check to see if the steerer on the fork bulged from overtightening. That would result in an inability to tighten the wedge. Not likely, but I have seen it before.

[yodelinpol]

How hard did you try to turn the bars? And how tight did you torque the bolt before you tried turning the bars? I ask only because I can visualize how the bolt could become stressed by twisting hard on the bars, which could lead to subsequent failure when you tightened more.

Since you had used the stem before, I'd also check the surfaces of the quill and wedge to make sure they are in good shape and don't have a defect that could prevent free movement.

Don't use a torque wrench so couldn't say. I tightened the bolt to where I felt comfortable with how tight I tightened it and had tightenned it in the past. I am at work but will closely inspect the wedge and bottom part of quill when I get home.

How much force should be applied when checking to see if the stem will move from side to side after tightening it into the steerer?

[yodelinpol]

You may have two or more things working together here -

1) the steerer maybe be stretched from over tightening the wedge bolt on the past. If you over tighten (frankly hard to do if you have any kind of "touch") it will make the steerer swell like a snake that ate a rodent. Once it stretched the fork is toast as you'll never get a stem to stay tight and the fork steerer is compromised. If you pull the fork and lay the steerer on a flat surface it will be obvious if the snake has eaten a large rodent.

2) the stem wedge angle and the stems wedge angle may not match. This happens when folks assume that the angle is standardized and combine parts from various stems.

3) you stem bolt was just plain fatigued. Think of the stress they are under 24/7 when they are tight. For years at a time they sit there being stretched and eventually they will fail. This is especially true with older Cinelli type stems with a long skinny bolt. "Modern" quill stems all came with short and fat bolts. This lessened bolt wind-up when being tightened.

4) the threads on the bolt may be way past their prime of may be dry which will put a huge twisting load on the bolt while NOT pulling the wedge up.


FWIW that final turn of the bolt when you thought you were tightening the bolt was really the bolt being twisted and breaking.

Does this help?

dave

This helps. It is an older nitto stem and the quill is pretty long (225 mm) so the bolt is very long and may just be old and skinny as well. It may have been dry as well. Like i said, the shorter newer nitto pearl works and holds like a charm.

If this shorter nitto pearl works fine and does not come loose, do you feel it may be a safety hazard at all for me to just use it for the time being?

I guess I am trying to avoid pulling the fork until next week if possible. I gotta ride this week and have a century this weekend. If you feel I should pull it I will.

[David Kirk]

This helps. It is an older nitto stem and the quill is pretty long (225 mm) so the bolt is very long and may just be old and skinny as well. It may have been dry as well. Like i said, the shorter newer nitto pearl works and holds like a charm.

If this shorter nitto pearl works fine and does not come loose, do you feel it may be a safety hazard at all for me to just use it for the time being?

I guess I am trying to avoid pulling the fork until next week if possible. I gotta ride this week and have a century this weekend. If you feel I should pull it I will.

Pull the fork. It's easy to do and it will tell all. Not doing so and having a badly bulged steerer will put your safety at risk.

Dave

[yodelinpol]

Pull the fork. It's easy to do and it will tell all. Not doing so and having a badly bulged steerer will put your safety at risk.

Dave

Will do. Thank you. And thanks to all for responses and advice.

[David Kirk]

Will do. Thank you. And thanks to all for responses and advice.

Thank you....... forks are cheaper than teeth.

dave

[FL_MarkD]

Check out the information on Sheldon Brown's page about the issue of 'bottoming out' a stem in the steering tube. Sometimes the bottom has a slope and it doesn't allow the entire wedge to contact the surface of the steering tube. That would explain why you couldn't get a good set with the long stem, but the shorter stem (depth, not reach length) would work.

http://sheldonbrown.com/handsup.html scroll to the bottom to see the diagram that explains the possible issue

Mark

[yodelinpol]

I saw that and considered it. It may be a contibutor. I'm gonna pull the fork in a few hours and check the steerer tube first for damage. If it checks out I will go from there. I will most likely put the Pearl back on for now if the tube is ok. I have to admit I am getting a little anxious here at work to get home and see what is up.

If it is damaged, I may be writing on Monday about doing this weekend's century on an old Nishiki fixed gear. I sure hope not, but.... man's gotta do.... well, you know. I ain't got the time or cash for awhile to take care of replacing my fork.

Thanks for the info.

Kenny

[yodelinpol]

You may have two or more things working together here -

1) the steerer maybe be stretched from over tightening the wedge bolt on the past. If you over tighten (frankly hard to do if you have any kind of "touch") it will make the steerer swell like a snake that ate a rodent. Once it stretched the fork is toast as you'll never get a stem to stay tight and the fork steerer is compromised. If you pull the fork and lay the steerer on a flat surface it will be obvious if the snake has eaten a large rodent.

2) the stem wedge angle and the stems wedge angle may not match. This happens when folks assume that the angle is standardized and combine parts from various stems.

3) you stem bolt was just plain fatigued. Think of the stress they are under 24/7 when they are tight. For years at a time they sit there being stretched and eventually they will fail. This is especially true with older Cinelli type stems with a long skinny bolt. "Modern" quill stems all came with short and fat bolts. This lessened bolt wind-up when being tightened.

4) the threads on the bolt may be way past their prime of may be dry which will put a huge twisting load on the bolt while NOT pulling the wedge up.


FWIW that final turn of the bolt when you thought you were tightening the bolt was really the bolt being twisted and breaking.

Does this help?

dave

Pulled the fork. All is well. Cleaned and regreased headset. Cleaned headtube and inside and outside of steerer. Greased outside of steerer. Got a new stem bolt for the technomic at the LBS. Greased the quill, bolt and bolt threads and wedge. Put it at the same location as when it broke. Voila. All is fine. Wedge held fine and plenty tight withought any over torquing. Feels solid. All seems smooth.

I am guessing it was most likely that the old bolt was just out of life from the years of stress and possibly dry and old threads. (so, answers #3 and # 4 above)

So now I have a little piece of mind about the steerer and new bolt being good to go, my headset has had its yearly cleaning and packing and I have learned something and gained some experience. Plus i have the shorter stem on there which was the original goal and will be a bit more comfortable on this weekend's century and until I get a little more core strength.

Thanks again.

PS. On Monday, I saw/rode next to the JKS that you showed at the 2008 NAHBS. It is a beauty.

[David Kirk]

Pulled the fork. All is well. Cleaned and regreased headset. Cleaned headtube and inside and outside of steerer. Greased outside of steerer. Got a new stem bolt for the technomic at the LBS. Greased the quill, bolt and bolt threads and wedge. Put it at the same location as when it broke. Voila. All is fine. Wedge held fine and plenty tight withought any over torquing. Feels solid. All seems smooth.

I am guessing it was most likely that the old bolt was just out of life from the years of stress and possibly dry and old threads. (so, answers #3 and # 4 above)

So now I have a little piece of mind about the steerer and new bolt being good to go, my headset has had its yearly cleaning and packing and I have learned something and gained some experience. Plus i have the shorter stem on there which was the original goal and will be a bit more comfortable on this weekend's century and until I get a little more core strength.

Thanks again.

PS. On Monday, I saw/rode next to the JKS that you showed at the 2008 NAHBS. It is a beauty.

Perfect. A happy ending.

Enjoy the ride.

dave