DANGER: Trek multitrack 7300 (hybrid) aluminum bracket sheers off, rips apart entire rear end of bike

In rec.bicycles.racing wrote:
Dan wrote:

snip

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. Several spokes are broken
and/or bent. 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.

I would be willing to bet that the manufacturer finds an excuse to not
do anything, even if the dealer goes to bat for you. It doesn't matter
what the actual cause of the failure was, it's whether or not they can
find a way to not do anything, since it's your word against their's.

Look, it was his own damn fault. Frames don't fail that way without
some measure of operator error. He should suck it up and buy a new
bike or frame and not expect Trek to cover for his mistakes.

You really want to avoid aluminum frames if at all possible, but you're
not going to find many $420 bicycles with chromoloy steel frames! Metal
fatigue is a huge problem with aluminum, and not just on bicycles. Of
course most of the time you'll be just fine, but it's those
catastrophic failures, that are much more likely to occur with
aluminum, that are scary. The derailleur hanger can be subjected to a
lot of stress, with not a lot of metal there.

This is flat out bull****.

I've broken my share of bikes. The really hairy frame failures have
all involved steel. The only damage I've done to any of the aluminum
bikes I've owned was my own damn fault.

The time I ripped the down tube out of the lower head lug in a crit,
it was a steel frame. The time I had a chain stay come loose from
the bottom bracket shell, it was steel. The time I was wondering
what the !@#$% was up with my front brake and realized, once I had
stopped, that the fork leg was failing at the crown, it was steel.

And the time I crashed and whacked an aluminum derailleur hanger, I
fixed it with a cresent wrench and an alignment tool. If it would
have failed later I'd have sucked it up and bought a new frame
because it would have been my own damn fault.

Derailleur hangers do not see a lot of stress unless someone screws
up.

Bob Schwartz


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