L
Luke
Guest
Two hours into my first day of a four day mini-tour, TWANG! I was
surprised: four years had passed since my last broken spoke -- and that
on a wheel I'd laced with an ornamental intertwined pattern.
The casualty was the right (drive) side spoke on a 36 spoke/3x rear
wheel built (as per the Bicycle Wheel) with 2mm straight gauge DT
stainless spokes and a Mavic Open Pro rim. Total mileage: approx.
15,000 KM. How odd: the spoke broke at the nipple rather than at the
bend. Inspection revealed that the nipple had bottomed out on the spoke
thread [1].
A week earlier an accident involving a kid and a dog upended the bike
and launched me over the bars. When the dust settled the worst damage
was to that same rear wheel: it had smashed against the curb in the
melee and was about 1cm out of true. A little twisting of the spoke
wrench and I was good to go. But the spoke that required the most
tightening was the one that ended up breaking a week following -- easy
to note because it was the right side spoke next to the valve stem.
Now even though the nipple had bottomed out, I wonder how great a role
this played in the spoke failure -- as is evident in the photo, the
nipple flats are in great shape and the post-accident truing session
did not involve any Herculean application of the spoke wrench. I'm
uncertain whether the primary cause of failure was an overtightened
spoke, a deficient spoke, or a combination of factors.
Luke
1. Click on 'Large' to view the photo at full size.
http://www.flickr.com/photo_zoom.gne?id=177134133&size=o
surprised: four years had passed since my last broken spoke -- and that
on a wheel I'd laced with an ornamental intertwined pattern.
The casualty was the right (drive) side spoke on a 36 spoke/3x rear
wheel built (as per the Bicycle Wheel) with 2mm straight gauge DT
stainless spokes and a Mavic Open Pro rim. Total mileage: approx.
15,000 KM. How odd: the spoke broke at the nipple rather than at the
bend. Inspection revealed that the nipple had bottomed out on the spoke
thread [1].
A week earlier an accident involving a kid and a dog upended the bike
and launched me over the bars. When the dust settled the worst damage
was to that same rear wheel: it had smashed against the curb in the
melee and was about 1cm out of true. A little twisting of the spoke
wrench and I was good to go. But the spoke that required the most
tightening was the one that ended up breaking a week following -- easy
to note because it was the right side spoke next to the valve stem.
Now even though the nipple had bottomed out, I wonder how great a role
this played in the spoke failure -- as is evident in the photo, the
nipple flats are in great shape and the post-accident truing session
did not involve any Herculean application of the spoke wrench. I'm
uncertain whether the primary cause of failure was an overtightened
spoke, a deficient spoke, or a combination of factors.
Luke
1. Click on 'Large' to view the photo at full size.
http://www.flickr.com/photo_zoom.gne?id=177134133&size=o