Breaking spokes on front Mavic OP

I think everything sounds reasonable if they are willing to fix them for free! If they are suggesting you have to pay for the repair/upgrade because you "ride too hard", then I would be complaining like crazy and finding another LBS if they did not give some satisfaction.

I was just wondering what brand of spokes the builder put on the front wheel. I have been building wheels for over 25 years and I am wondering if when the wheels were built if he over tensioned the wheel and they have prematurely failed. At your weight you should not be breaking spokes. Lots of production wheels are built these days with radially spoked and we don't see problems with them. I would get them replaced by a good builder (which is hard to find). I would trust someone that has been in the bike business for years and not trust someone that has been in the business for a couple of years. It is hard to find someone that is an old fart that is still in the business.

serenaslu said:

[font=Times New Roman]

[font=Times New Roman]Okay, here's the deal. With my new ride, acquired in late may, I got Mavic Open Pro's 32-hole with Ultegra hubs. They were built up by the LBS owner who is supposed to be a good wheelsmith from everyone I have talked to, with DT Comp spokes 15-16-15 2X in the front and 14-15-14 3X drive-side 2X non-drive-side in the rear. Everything was fine for about the first 1500 miles (had them tuned-up at 300-400 miles). Then at around 1500 miles I popped a front spoke coming up a modest climb. Since then (I now have a little over 2100 miles on them), I have lost three more front spokes on separate occasions. Rear has been fine. The wheel is staying true and is making no noise up to the dreaded death-ping which has always occurred just smoothly pedaling along. Road quality that I ride is not always the greatest with uneven pavement joints at times and some RR crossings, but I have definitely seen far worse.[/font]
[font=Times New Roman]The wheel-builder says that there is nothing wrong with the rim or hub and that I am just riding it too hard or on bad roads for those spokes (which he of course intitially specified) (which at about 155lbs, I find hard to believe on a high spoke count wheel like this) and says that I need to redo the front with 14-15-14 3X.[/font]

[font=Times New Roman]I took it to another LBS and they said they could see nothing wrong with the wheel or spokes' gauge, but would suggest going to 3X on the front.[/font]

[font=Times New Roman]This almost weekly routine has really gotten more than irritating and am just wondering if the wheelbuilder’s explanation and solution sounds reasonable.[/font]

[/font]

Stress Relieve!
It's isn't the spoking pattern or the gague of the spokes.
Fatigue is the cause, and it's coming due to lack of proper stress relieving.
Stress relieving takes a few minutes but a lot of strength and gloved hands; you just can't squeeze the spokes hard enough without leather... or cycling gloves. I have spoke callouses in my hands even through the gloves.

pudster said:

I was just wondering what brand of spokes the builder put on the front wheel. I have been building wheels for over 25 years and I am wondering if when the wheels were built if he over tensioned the wheel and they have prematurely failed. At your weight you should not be breaking spokes. Lots of production wheels are built these days with radially spoked and we don't see problems with them. I would get them replaced by a good builder (which is hard to find). I would trust someone that has been in the bike business for years and not trust someone that has been in the business for a couple of years. It is hard to find someone that is an old fart that is still in the business.

DT-Swiss Competitions were used all around. FWIW, the guy has been building wheels since the early 1980's.

daveornee said:

Stress Relieve!
It's isn't the spoking pattern or the gague of the spokes.
Fatigue is the cause, and it's coming due to lack of proper stress relieving.
Stress relieving takes a few minutes but a lot of strength and gloved hands; you just can't squeeze the spokes hard enough without leather... or cycling gloves. I have spoke callouses in my hands even through the gloves.

Thanks, but the wheel's spokes were thoroughly stress relieved before initial build and after subsequent adjustments.

I don't think that stress relieving is the problem either because if they were not stress relieved after building they probably would have gone out of true in first few miles. I guess that I just think the front wheel tension was too high when built and when spokes are near there fatigue limit they will break after a while even if you do weigh 150 lbs. I don't see much reasoning behind his spoke patterns so I thought maybe he was not experianced, sorry about that.

serenaslu said:

DT-Swiss Competitions were used all around. FWIW, the guy has been building wheels since the early 1980's.

Thanks, but the wheel's spokes were thoroughly stress relieved before initial build and after subsequent adjustments.

OK, if that is what you want to believe.
However, I want know how the spokes were stress relieved especially "before the intial build".

Where did the spokes break?

Where the spokes aligned at the hub and nipple?

Have you read "the Bicycle Wheel" by Jobst Brandt?

pudster said:

I don't think that stress relieving is the problem either because if they were not stress relieved after building they probably would have gone out of true in first few miles. I guess that I just think the front wheel tension was too high when built and when spokes are near there fatigue limit they will break after a while even if you do weigh 150 lbs. I don't see much reasoning behind his spoke patterns so I thought maybe he was not experianced, sorry about that.

Please explain how not stress relieving would make the wheels go out of true.. other than breaking spokes... especially in the first few miles.
Remember stress relieving is not removing spoke wind-up.

Please also explain how what is too high a tension, how you get it with 15/16 spoke, and how it breaks spokes.

daveornee said:

OK, if that is what you want to believe.
However, I want know how the spokes were stress relieved especially "before the intial build".

Hell, I don't know what to believe that's why I appreciate the feedback.
Should have read "before riding after the initial build", my bad.
He uses a gizmo that looks sort of like a modified pair of vicegripe or similar type pliers that have funky rubber-coated inverted v-shaped jaws, (a homemade tool I suspect) that he compresses across several crossed spokes towards the center of the spoke length . No idea if that is the best way or not.

Quoted post said:

Where did the spokes break?

They failed at the usual spot on the spoke bend/head interface.

Quoted post said:

Where the spokes aligned at the hub and nipple?

I can't say how they were initially but I haven't noticed any obvious problems with head or nipple seating since I began scrutinizing them.

Quoted post said:

Have you read "the Bicycle Wheel" by Jobst Brandt?

No. Not the whole book. Just various excerpted sections from it on the net.

serenaslu said:

Hell, I don't know what to believe that's why I appreciate the feedback.
Should have read "before riding after the initial build", my bad.
He uses a gizmo that looks sort of like a modified pair of vicegripe or similar type pliers that have funky rubber-coated inverted v-shaped jaws, (a homemade tool I suspect) that he compresses across several crossed spokes towards the center of the spoke length . No idea if that is the best way or not.

They failed at the usual spot on the spoke bend/head interface.

I can't say how they were initially but I haven't noticed any obvious problems with head or nipple seating since I began scrutinizing them.

No. Not the whole book. Just various excerpted sections from it on the net.

Well, the whole book is good, but even though I have read it many times, it ends up coming off the shelf for reference in instances just like this.
The funky tool you describe just won't do the job. Read that section of "the Bicycle Wheel" . It takes significant over-tensioning to accomplish to the point where the spokes will never be taken during any riding situation.
Seating isn't the objective of stress relief, although it often happens and isn't a bad side effect.

Spoke alignment is also important. Since it is your front wheel that is giving you trouble and not the back wheel, where there is a more complicated situation of stresses and load sharing, I suspect that spoke alignment could have contirbuted to spokes breaking. Sometimes the spokes themselves and the physical characteristics of the spoke hub interface can be significant contributors to fatigue failure. Specifically, the length of the spoke from head to elbow varies within DT's manufacturing revisions by .85 mm. There is also a variance in spoke hole size, shape, and hub flange thickness. The point to spoke alignment is to support the end of the spoke with the hub flange at the elbow end and the nipple at the rim end. You can see the before and after illustrations in "the Bicycle Wheel" in the section "improving the spoke line". "If there is an unsuported bend in the spoke, it will flex with changing load causing fatigue and early failure."
The unsupported part of the spoke should be straight as a tight string running from the edge of the hub flange to the top of the nipple.
If your spokes look like the "Before" illustration (Spoke Line at Hub) shown in Figure 33 or whatever figure it is in your edition... ; you need to get that issue resolved. Spokes with greater distance from head to elbow and/or in hubs with thinner flanges take more work to get this job done.
It also won't hurt anything to stress relieve again, and you should stress relieve again if you do any further improving to the spoke line, as plastic deformation puts residual stress in.

daveornee said:

Well, the whole book is good, but even though I have read it many times, it ends up coming off the shelf for reference in instances just like this.
The funky tool you describe just won't do the job. Read that section of "the Bicycle Wheel" . It takes significant over-tensioning to accomplish to the point where the spokes will never be taken during any riding situation.
Seating isn't the objective of stress relief, although it often happens and isn't a bad side effect.

Spoke alignment is also important. Since it is your front wheel that is giving you trouble and not the back wheel, where there is a more complicated situation of stresses and load sharing, I suspect that spoke alignment could have contirbuted to spokes breaking. Sometimes the spokes themselves and the physical characteristics of the spoke hub interface can be significant contributors to fatigue failure. Specifically, the length of the spoke from head to elbow varies within DT's manufacturing revisions by .85 mm. There is also a variance in spoke hole size, shape, and hub flange thickness. The point to spoke alignment is to support the end of the spoke with the hub flange at the elbow end and the nipple at the rim end. You can see the before and after illustrations in "the Bicycle Wheel" in the section "improving the spoke line". "If there is an unsuported bend in the spoke, it will flex with changing load causing fatigue and early failure."
The unsupported part of the spoke should be straight as a tight string running from the edge of the hub flange to the top of the nipple.
If your spokes look like the "Before" illustration (Spoke Line at Hub) shown in Figure 33 or whatever figure it is in your edition... ; you need to get that issue resolved. Spokes with greater distance from head to elbow and/or in hubs with thinner flanges take more work to get this job done.
It also won't hurt anything to stress relieve again, and you should stress relieve again if you do any further improving to the spoke line, as plastic deformation puts residual stress in.

Thanks for the info. I just decided to do a quick and dirty squeeze of the spokes and on the third set popped the head off yet another one with virtually no force. That's when it struck me that every friggin' one that has failed has been an inbound (ones with the spoke head on the inside of the hub, I am never sure which is correctly referred to as inbound and outbound) spoke!

I guess that you are right. I gave the builder too much credit that he had stress relieved the wheel because the wheel did not come out of true right away so my thinking is that he knows how to reduce twist in the spokes when building. I do think that it is easy for someone to overtension a wheel when they use spokes that are 15 guage at the bend. I guess that I could never be a writer because I can't seem to get my thinking in writing, sorry.

pudster said:

I guess that you are right. I gave the builder too much credit that he had stress relieved the wheel because the wheel did not come out of true right away so my thinking is that he knows how to reduce twist in the spokes when building. I do think that it is easy for someone to overtension a wheel when they use spokes that are 15 guage at the bend. I guess that I could never be a writer because I can't seem to get my thinking in writing, sorry.

DT 15/16 Competition spokes take over 200 kgf in their linear elastic range.
It would be difficult to get them to that tension due to nipple/eyelet friction... even with good practices/good lubrication/good spoke wrench. At 200 kgf they have stretched around 2 mm. If you continue much past 200 kgf, you will stretch them by another 4 mm before they will yield.

Bringing them up to that tension shold not be tried at home!

However, you would run out of thread on the spoke before that happened, unless the spoke length calculation was quite a bit off on the short side.
Wind up that is hard to control and roundin off the nipples would often happen in the process of going up to 200 kgf.

serenaslu said:

...That's when it struck me that every friggin' one that has failed has been an inbound (ones with the spoke head on the inside of the hub,

A spoke is delivered with a straight angle bend and needs to be adjusted to reach a correct spoke line. Maybe your wheelbuilder forgot that part and simply laced&tightened the wheel?
Or maybe there's something about the elbow length and flange thickness that makes for a better interface on one side? (I've read about that you sometimes need to adjust elbow length by adding small washers to get optimum results).