I know I'm going to get chastised by the opinionated elitist dorks in
this forum who think the only good wheel is hand built by an LBS for
this post, but I _do_ need some technical advice with regards to a
freehub dragging issue. this is not the typical freehub drag that you
see when you spin the wheel up in a workstand.
On a recent trip to the north georgia mountains, I was descending
hogpen gap and topping 50 mph, when the freehub on my 3 year old
ksyrium SL started making a lowpitched squeal similar to an out-of-toe
brake on the rim. I slowed enough so it was safe to look back, and the
freehub was dragging/binding to the point where the chain had dropped
in between the stay and the wheel, and the dérailleur had been forced
into max tension. For the duration of the ride, on high speed
descents, I was forced to ride the brakes and spin my 53x11. The
previous three days had no similar incidents, including descents of
Woody Gap, Wolfpen gap, Aska Road, and Brasstown Bald. I switched to
my older Vector Pro (Hugi 240 hub) for duration of the trip.
In the stand, there did not seem to be any play in the freehub or
wheel bearings. Spinning the 53x11 as fast as possible by hand could
not spin the wheel fast enough to elicit the failure, and notably
there was only a _slight_ amount of drag when letting the wheel spin
on its own after the crank stopped turning.
The noise seems to be a bearing that had enough play to break into an
oscillation. Of course, it may have been simply that the 80 mile ride
in the rain the day before had effectively removed all the lubrication
from the hub guts, and the high speed descent was forcing the bearing
to bind.
Has this occurred to others? Is it a MFG flaw? If it's excessive play,
can it be compensated for by increasing the side load or does the
design of the freehub prevent that? Will a simple rebuild and
repacking solve the problem? I don't have any hills locally that I can
sustain a 50 MPH descent for long enough to verify a repair, but if
this is an indication of an impending failure, would appreciate some
insight as to what steps can be taken to get prevent it.
Wheel - Ksyrium SL ~ 3000 miles
I weigh 140#
Heavy rain the day before the failure
Earlier the same day I descended wolfpen gap and brasstown bald with
no incidents.
Please don't respond if your only comment is that this is what I get
for riding a ksyrium. I will respond in such instances with levels of
vitriol and hatred that will cause your computer to blush and have you
considering medication therapy.
Thank you, and have a nice day.