> Hey all,
> I rebuilt some trusty old hubs with new rims and spokes (DA 7700 hubs, Sapim Race 14/15, Velocity A23 rims) using a cheapo truing stand and tensioning by feel but I'm decently skilled at this so the wheels turned out nicely (or so I thought).
> Anyway, after maybe 1000 miles of use I broke a rear NDS spoke at the *** during a ride, didn't notice it happen, wasn't because of a severe impact. ?I replaced it with a 14 gauge spoke of the same length and trued it back up. ?Now after a couple hundred additional miles I've found I've busted the replacement spoke.
> What the heck? ?I find it really peculiar that both breaks happened in the same spot. ?I'm not a great wheelbuilder but I've been building my own for many years and prior to this I'd never busted a spoke. ?The rim seemed fine while building it.
> Any advice much appreciated.
I assume that you properly laced the wheel and did not lace the left
hand spokes in to the right hand holes. That can create a really
acute angle and stress on the threaded end of the spoke. I've broken
spokes at the *** end when I didn't bed them in or make any effort
to adjust the angle -- and generally when I under-tensioned the wheel
which allowed more spoke movement. So do your stress relief and side
load to bed in the spokes and wind them up to tension -- 100kgf. If
you don't have a tensiometer, go squeeze another good rear wheel for
Why you have a problem at just one spoke hole is a mystery. Is the
spoke hole out of line with the other spoke holes, or is the ***
off angle compared to the other ***s? The only explanation I can
think of is that the *** is bad (I assume that you re-used the same
14g ***), or there is a problem with the drilling that causes the
*** to be at an even harder angle to the spoke, or the rim has a
high spot, and the spoke is over-loaded. But you would probably feel
that building the wheel, and in fact, you would probably be rounding
off the *** to put enough tension on the spoke to break it.
Other possibilities are: (1) bad luck, (2) demonic possession, and (3)
vandals. In that order. My $.02.
-- Jay Beattie.