In article <[email hidden]>, Ben
[email hidden] says...
Quoted message said:Hi,
I realise remote diagnosis of bike problems is difficult, but what do
people think, before I ask my LBS about it :
I have a Dawes horizon which has done about 10000 miles, and been kept
in good nick
I took it in for a service recently - clean and relube of everything,
change worn bits and pieces.
I subsequently noticed (though there may be no link) an odd noise from
- possibly - the bottom bracket
The noise reminds me of the sound those metal ball conservation of
momentum desk toys make
Newton's cradle :-)
Quoted message said:- a metallic, irregular click clacking -
roughly once or twice per revolution of the cranks, but not coinciding
with any particular crank position
The noise disappears when free-wheeling, and varies in intensity when
pedalling
The noise is completely independant of what gear I am in
This in no way impedes the bikes functionality, but perhaps it is
indicative of something? Could it be something to do with the bottom
bracket bearings?
If the bearings are too loose you should be able to detect sideways play
- check with the crank in several positions as uneven wear can create
tight spots and loose spots. Also look for movement between the bottom
bracket cups and the frame when you do this - movement might occur if
the cups haven't been properly tightened or if the thread in the frame
is damaged. The cups should also be sitting square in the frame. To
check the bearings aren't too tight remove the cranks and rotate the
axle by hand (with the cranks fitted you have too much leverage to
easily tell if the bearing are too tight).
Clicks and clunks during pedalling can have many causes - the
stem/steerer, bar/stem, crank/axle, crank/chainring, pedal/crank or
saddle/seatpost interfaces are common culprits. Overtightened or
cracked bearings can also be noisy, as can unevenly tensioned spokes.
One of my favourite worrying noises is the one you get when the sticky-
out end of the front derailleur cable catches against the crank as you
pedal, or catches your leg and flicks back against something else.
