On Sun, 27 Mar 2005 21:16:11 CST, Dan may have
said:

Hi,

Because this is a hybrid I'm not sure whether to place it in racing or
off-road. But here goes my story.

Saturday afternoon I was riding along a clean flat nature trail; no
sticks in the gears, no nothing. I was going at an even speed of
about 20-25mph in the next-highest gear when all of a sudden I hear a
*SNAP*, then something smashed into the rear spokes, causing an almost
instant stop. I was lucky I wasn't going downhill when this occurred,
or I would've flown over the handlebars.

It turns out that a small piece of the aluminum frame supporting the
gear shifter wore out due to metal fatigue. The shifter mechanism
ripped off the aluminum frame, got caught in the rear spokes, and
destroyed the entire rear end of the bike.

I find a different analysis more plausible; the rear derailleur cage
is much more likely to have snagged in the spokes, following the wheel
around and ripping the der support from the dropout in the process.
The der support tab has so little strain on it that it will not fail
due to "metal fatigue" even after an extremely long period in service.
There are at least three other ways by which the cited failure could
occur in my experience.

Several spokes are broken
and/or bent.

Quite typical of a spokejam due to der cage snagging.

The shifter mechanism is bent in several places, the
shifter wire is shredded, and the front crank apparatus also has some
damage due to the sudden awkward pull on the chain.

This should tell you something. Had the der mounting tab merely
failed, the der would have dropped off and hung from the chain, but
would not have been likely to get into the spokes; the der has to be
firmly mounted and the der cage extended (which won't be the case if
the der's mount breaks) in order for the cage to be able to grab the
spokes.

I was not happy. I had to walk 8 miles home while contending with a
pair of minor stress fractures in the legs (I was biking because I
can't run for the moment). I've contacted the dealer but so far no
reply. This $420 bike is just barely over 2 years old, with less than
500 miles on it. I expected to get more than a dollar per mile for
this bike, and I'm really not happy with Trek's poor design of this
frame and model.

If the dealer or Trek will support the repair of this obvious
manufacturer's defect, I will keep you apprised.

I suspect that failure analysis will determine that either the der had
been bent prior to the incident, putting its cage swing path into the
conincal region of the drive-side spokes, or that the der was stiff
due to congealed lubricant producing a motion pattern that put the der
into the spokes. I have had both types of failure occur; neither
would be a warranty matter.

Keep us informed in any event; it will be instructive for all
concerned if there's an actual defect involved.

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