Factor Fork Failures
03-30-21, 10:31 AM
#1
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Factor Fork Failures
That should be Factor Fork Failures.
https://cyclingtips.com/2021/03/factor-finally-sheds-light-on-that-broken-ostro-vam-steerer-tube/e
The problem seems to stem from the all internal cable routing at the head tube.
https://cyclingtips.com/2021/03/factor-finally-sheds-light-on-that-broken-ostro-vam-steerer-tube/e
The problem seems to stem from the all internal cable routing at the head tube.
03-30-21, 03:02 PM
#2
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Maybe this link will be the one you intended....
https://cyclingtips.com/2021/03/fact...-steerer-tube/
https://cyclingtips.com/2021/03/fact...-steerer-tube/
03-31-21, 09:12 AM
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I read the Cycling Tips article this morning. I don't know that I'd feel comfortable with the company's response to consumers. They suggest contacting Factor for a new compression plug if customers are having trouble keeping the headset tight, but replaced the forks on all of their team bikes.
03-31-21, 11:13 AM
#4
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Upon the conclusion of Factor’s investigation, Shrive says the issue boiled down to out-of-spec compression plugs, not an inherent problem with the carbon fiber steerer tube itself.
“We had a batch issue with our compression plug that saw the outside surface receive a clear anodize coating over the specified sand blast to white metal,” he explained. “This caused the surface roughness to be too low and led to preload issues with the headset. The team responded at camps and early season races by torquing these progressively higher, and finally by bonding in the plug while tightening it to ensure the headset stayed tight.
“This outward force caused a discontinuity in the fiber path and a distortion in the tube that led to Tom’s failure by concentrating the compressive bending stress at the point of discontinuity, instead of allowing the steerer to more uniformly distribute that stress over the length of it. I dealt with a similar issue to this with [UK Continental team] One Pro on the S5 in about 2015 [Shrive was formerly the director of engineering at Cervelo — ed.] when they used expansion plugs against recommendations and sheared their steerers.”
Compounding the issue was an unexpected change in the plug’s taper geometry that altered how it expanded inside the steerer tube. Instead of exerting uniform force along the inner wall of the steerer tube, the plug was expanding more at the bottom than at the top, which Shrive says made sense given that Van Asbroeck’s steerer tube failed right at the lower edge of the plug, not at the split ring on the upper headset bearing where you’d normally see the highest stresses.
Great that they figured out the issue, even if it is the most insanely complicated issue ever created in the history of history.
“We had a batch issue with our compression plug that saw the outside surface receive a clear anodize coating over the specified sand blast to white metal,” he explained. “This caused the surface roughness to be too low and led to preload issues with the headset. The team responded at camps and early season races by torquing these progressively higher, and finally by bonding in the plug while tightening it to ensure the headset stayed tight.
“This outward force caused a discontinuity in the fiber path and a distortion in the tube that led to Tom’s failure by concentrating the compressive bending stress at the point of discontinuity, instead of allowing the steerer to more uniformly distribute that stress over the length of it. I dealt with a similar issue to this with [UK Continental team] One Pro on the S5 in about 2015 [Shrive was formerly the director of engineering at Cervelo — ed.] when they used expansion plugs against recommendations and sheared their steerers.”
Compounding the issue was an unexpected change in the plug’s taper geometry that altered how it expanded inside the steerer tube. Instead of exerting uniform force along the inner wall of the steerer tube, the plug was expanding more at the bottom than at the top, which Shrive says made sense given that Van Asbroeck’s steerer tube failed right at the lower edge of the plug, not at the split ring on the upper headset bearing where you’d normally see the highest stresses.
Great that they figured out the issue, even if it is the most insanely complicated issue ever created in the history of history.
04-01-21, 08:44 AM
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Upon the conclusion of Factor’s investigation, Shrive says the issue boiled down to out-of-spec compression plugs, not an inherent problem with the carbon fiber steerer tube itself.
“We had a batch issue with our compression plug that saw the outside surface receive a clear anodize coating over the specified sand blast to white metal,” he explained. “This caused the surface roughness to be too low and led to preload issues with the headset. The team responded at camps and early season races by torquing these progressively higher, and finally by bonding in the plug while tightening it to ensure the headset stayed tight.
“This outward force caused a discontinuity in the fiber path and a distortion in the tube that led to Tom’s failure by concentrating the compressive bending stress at the point of discontinuity, instead of allowing the steerer to more uniformly distribute that stress over the length of it. I dealt with a similar issue to this with [UK Continental team] One Pro on the S5 in about 2015 [Shrive was formerly the director of engineering at Cervelo — ed.] when they used expansion plugs against recommendations and sheared their steerers.”
Compounding the issue was an unexpected change in the plug’s taper geometry that altered how it expanded inside the steerer tube. Instead of exerting uniform force along the inner wall of the steerer tube, the plug was expanding more at the bottom than at the top, which Shrive says made sense given that Van Asbroeck’s steerer tube failed right at the lower edge of the plug, not at the split ring on the upper headset bearing where you’d normally see the highest stresses.
Great that they figured out the issue, even if it is the most insanely complicated issue ever created in the history of history.
“We had a batch issue with our compression plug that saw the outside surface receive a clear anodize coating over the specified sand blast to white metal,” he explained. “This caused the surface roughness to be too low and led to preload issues with the headset. The team responded at camps and early season races by torquing these progressively higher, and finally by bonding in the plug while tightening it to ensure the headset stayed tight.
“This outward force caused a discontinuity in the fiber path and a distortion in the tube that led to Tom’s failure by concentrating the compressive bending stress at the point of discontinuity, instead of allowing the steerer to more uniformly distribute that stress over the length of it. I dealt with a similar issue to this with [UK Continental team] One Pro on the S5 in about 2015 [Shrive was formerly the director of engineering at Cervelo — ed.] when they used expansion plugs against recommendations and sheared their steerers.”
Compounding the issue was an unexpected change in the plug’s taper geometry that altered how it expanded inside the steerer tube. Instead of exerting uniform force along the inner wall of the steerer tube, the plug was expanding more at the bottom than at the top, which Shrive says made sense given that Van Asbroeck’s steerer tube failed right at the lower edge of the plug, not at the split ring on the upper headset bearing where you’d normally see the highest stresses.
Great that they figured out the issue, even if it is the most insanely complicated issue ever created in the history of history.
Now, whether or not that is the real cause is another thing entirely!
Last edited by Erzulis Boat; 04-01-21 at 08:52 AM.
04-01-21, 11:50 AM
#6
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It's overly complicated in that it's creating a solution for an issue that is only an issue because of an overly complicated design.
Aero makes sense...to a point. When design gets this complicated to make it work, its either poor design or trying to do too much.
Notice not all design and routing is done like Factor's.
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