Clunk

gumby said:

Gday peeps
My ride, an orbea vento running campag veloce has turned one, done
about 5500kays of training and riding on this bike. I have regular
cleaned and lubed the chain during this time.
Question. I have bought a set of campag eurus wheels with a 12-25
chorus cassette. I have done about 250kays of racing and tt's on this
set. Everytime I race on the eurus when I freewheel and then put power
on, without fail I get a huge metallic clunk through the frame, doesnt
happen with the campag vento wheels (veloce).
Now DeF who is a bike bling addict from way back suggests the chain is
stretched and the veloce cassette has worn with it too, I use mainly
the 19 and 17 cogs. I thought it may have been the LBS not locking the
lockring down tight enough on the chorus.
Is he likely to be right, and should I just get a new chain and keep
the veloce cassette?
Steven

I had the same issue and it turned out to be a weak return spring on the
freewheel ratchet. Because the spring wasn't returning the ratchet
pawls back out fully, the ratchet would only engage on the tip of the
teeth and when I powered back on, the pressure would force the pawls
fully outwards, smacking against the bottom of the teeth inside the hub.
This would cause an almighty clunk that really concerned me until the
LBS replaced the spring. This happened when the bike was fairly new, so
it seems to be a 'burn in' issue. Funnily enough, it started just after
my first Kings Park TT with about the same mileage on it as your wheels.

Of course, your chain may well be worn, but if it was worn enough to
cause a clunk, it would be due to jumping teeth which would happen all
the time while you accelerate, not just the once after you stop
freewheeling and power on.

--
BrettS

"BrettS" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

gumby said:

Gday peeps
My ride, an orbea vento running campag veloce has turned one, done
about 5500kays of training and riding on this bike. I have regular
cleaned and lubed the chain during this time.
Question. I have bought a set of campag eurus wheels with a 12-25
chorus cassette. I have done about 250kays of racing and tt's on this
set. Everytime I race on the eurus when I freewheel and then put power
on, without fail I get a huge metallic clunk through the frame, doesnt
happen with the campag vento wheels (veloce).
Now DeF who is a bike bling addict from way back suggests the chain is
stretched and the veloce cassette has worn with it too, I use mainly
the 19 and 17 cogs. I thought it may have been the LBS not locking the
lockring down tight enough on the chorus.
Is he likely to be right, and should I just get a new chain and keep
the veloce cassette?
Steven

I had the same issue and it turned out to be a weak return spring on the
freewheel ratchet. Because the spring wasn't returning the ratchet pawls
back out fully, the ratchet would only engage on the tip of the teeth and
when I powered back on, the pressure would force the pawls fully outwards,
smacking against the bottom of the teeth inside the hub. This would cause
an almighty clunk that really concerned me until the LBS replaced the
spring. This happened when the bike was fairly new, so it seems to be a
'burn in' issue. Funnily enough, it started just after my first Kings
Park TT with about the same mileage on it as your wheels.

Of course, your chain may well be worn, but if it was worn enough to cause
a clunk, it would be due to jumping teeth which would happen all the time
while you accelerate, not just the once after you stop freewheeling and
power on.

--
BrettS

Swap the cassettes over and see if the problem follows the cassette or the
wheel.

Peter

vesel said:

"BrettS" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

gumby said:

Gday peeps
My ride, an orbea vento running campag veloce has turned one, done
about 5500kays of training and riding on this bike. I have regular
cleaned and lubed the chain during this time.
Question. I have bought a set of campag eurus wheels with a 12-25
chorus cassette. I have done about 250kays of racing and tt's on this
set. Everytime I race on the eurus when I freewheel and then put power
on, without fail I get a huge metallic clunk through the frame, doesnt
happen with the campag vento wheels (veloce).
Now DeF who is a bike bling addict from way back suggests the chain is
stretched and the veloce cassette has worn with it too, I use mainly
the 19 and 17 cogs. I thought it may have been the LBS not locking the
lockring down tight enough on the chorus.
Is he likely to be right, and should I just get a new chain and keep
the veloce cassette?
Steven

I had the same issue and it turned out to be a weak return spring on the
freewheel ratchet. Because the spring wasn't returning the ratchet pawls
back out fully, the ratchet would only engage on the tip of the teeth and
when I powered back on, the pressure would force the pawls fully outwards,
smacking against the bottom of the teeth inside the hub. This would cause
an almighty clunk that really concerned me until the LBS replaced the
spring. This happened when the bike was fairly new, so it seems to be a
'burn in' issue. Funnily enough, it started just after my first Kings
Park TT with about the same mileage on it as your wheels.

Of course, your chain may well be worn, but if it was worn enough to cause
a clunk, it would be due to jumping teeth which would happen all the time
while you accelerate, not just the once after you stop freewheeling and
power on.

--
BrettS

Swap the cassettes over and see if the problem follows the cassette or the
wheel.

Peter

Thanks for responses.
I am going to go with Brett S and the ratchet pawls diagnosis.
Reason, put the eurus on on Sunday and apart from the bloody awful
creaking from around the bottom bracket, the 'clunk' has gone. Though
there wasnt a lot of freewheeling going on on Sunday morning. Wangara is
a different course to Kewdale innit?

Eurus now done a definate 260km. Burnt in? It was warm that for sure.
Steven

Gumby said:

Thanks for responses.
I am going to go with Brett S and the ratchet pawls diagnosis.
Reason, put the eurus on on Sunday and apart from the bloody awful
creaking from around the bottom bracket, the 'clunk' has gone. Though
there wasnt a lot of freewheeling going on on Sunday morning. Wangara is
a different course to Kewdale innit?

Ah, yes. Did you go faster up the hill than down it?

--
BrettS

BrettS said:

Gumby said:

Thanks for responses.
I am going to go with Brett S and the ratchet pawls diagnosis.
Reason, put the eurus on on Sunday and apart from the bloody awful
creaking from around the bottom bracket, the 'clunk' has gone. Though
there wasnt a lot of freewheeling going on on Sunday morning. Wangara
is a different course to Kewdale innit?

Ah, yes. Did you go faster up the hill than down it?

--
BrettS

Gumby forgot to mention how he went in that race. From his
three starts in C-grade with the vets he's come 5th, 2nd and
now 1st so well done him! The handicapper has his eye on him.

DeF

--
e-mail: [email hidden]
To reply, you'll have to remove finger.

Yes well Thanks for that DeF! I am now going to do a couple of TT's
and stay away from the crits, I am a bit like a greyhound after the
rabbit in those things. Not sure I want to be in B grade at this stage
of the season.