Broken spokes -> NEAR DEATH EXPERIENCE!!!

[jtopiso_imp]

That's a shame that happened.

Spoke breakage is not common but not rare either. The early Bonnevilles 2000-2003 had the issue so often the forums were asking for a recall. It happened to my 2003 Centenial Edition Bonnie as well. I went around a left hander and felt a pop, then more pops and the back end got all wobbly. Had probably a dozen or so broken spokes all together. Triumph thankfully paid for a new wheel.

Right now there is a internet blog of a guy on a BMW GS who's front wheel spokes all disintegrated on him. More reports of similar problems followed. They are wanting a recall on BMW spoked wheels.

Spokes are like the span of a bridge. EAch spoke shares and spreads the pressure between them. If one spoke goes, that puts extra pressure on the remaining spokes, which end up flexing more than they are designed and then another breaks, putting even more pressure on the remaining spokes. pretty soon it's a lost cause and most break.

Spokes look good, they flex making the ride softer, but they also sometimes break.

Well... spokes are like "stay-cables" on a bridge. The work in tension only, so they don't flex: they just stretch.
Preload on them has to be high enough so load cycles are small and fatigue is minimized (load will be small compared to tension, so cycle amplitude is small). If load is to high, you could have metal yield (so tension becomes VERY low), ir it can just snap (this depends on the alloy). In any case: spoke preload is VERY important.

Without knowing this case, I'd point the probable causes to be:

-wrong servicing (i.e. bad preload on spokes) -> most probable
-bad batch of spokes -> unlikely: we would have heard of more.
-corrosion failure -> unlikely: we would have heard of more.
-bad design -> VERY unlikely: spoke rim design is not exactly a new unknown technology

This is just my opinion, but if I had to bet... this failure can be from something very simple like a unit conversion problem from [Nm] to [lb·ft].

I'm glad nothing irreversible happened!
Some interesting info I've just found regarding spoked wheels:

http://poehali.net/attach/Bicycle_Wheel_...Brandt.pdf

You cannot rule the last three as unlikely without further investigation. I've seen all of these types of failures in my 20+ years as a mechanical engineer across many mature product lines and industries.

The fact Honda changed the spoke wheel design tells me they MAY have been aware of a design issue OR the change was to cut cost. However, since the materials used after the design change are more expensive, I doubt it was a cost cut.

Indeed: I can't rule anything out, but with the information we have, that's my guess. But it's just a guess.

Honda can change design or materials due to several reasons: cost, a design issue, or just because they wanted to offer something different, even if it's more expensive (if they think it adds value and they will sell more). E.g. double walled stainless headers are not there to correct any design issues, and they have to be more expensive to make.

And again: it can be anything, but if I had to put my money, I'd bet for wrong servicing.

Now I ask: how do they check preload on spokes? do they meassure torque on the nut or do they messure actual tension on the wire spoke?

Torque meassures are VERY dependant on how clean is the thread, the nut seat friction, and the calibration of the torque wrench. All this can add up to a lot of error (~30%). Sometimes all this doesn't matter, but... it could.