Common "thunk" in drive

In article said:

Maybe someone could please point me in the right technical direction as I just don't see anything
upon inspection and I've lost trust in my bike shop technican's expertise (long story). When
pedaling uphill where the bike has the most load on the gears, chain, etc., I feel a clunk
throughout the drive. Problem happens frequently but not readily repeatable. I'm sure this is a
common problem and my question to this posting is primarily most common sources that people have
seen. Any inputs would be greatly appreciated. Thanks.

First guess is a skipping chain due to wear on the cog and chain. Does it happen primarily in just
one gear? Have you checked the chain for wear (1/16" in 12" is a useful wear limit)?

--
Ryan Cousineau, [email hidden] sfu.ca~rcousineOpen ↗ President, Fabrizio Mazzoleni Fan Club

I'll have to check. I tends to happen in multiple gears. I thought that the derailer was not setup
properly but I don't really see a problem there. Thanks for your input.

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

Quoted message said:

In article said:

Maybe someone could please point me in the right technical direction as

I

Quoted message said:

Quoted message said:

just don't see anything upon inspection and I've lost trust in my bike shop technican's
expertise (long story). When pedaling uphill where the bike

has

Quoted message said:

Quoted message said:

the most load on the gears, chain, etc., I feel a clunk throughout the

drive.

Quoted message said:

Quoted message said:

Problem happens frequently but not readily repeatable. I'm sure this is

a

Quoted message said:

Quoted message said:

common problem and my question to this posting is primarily most common sources that people have
seen. Any inputs would be greatly appreciated. Thanks.

First guess is a skipping chain due to wear on the cog and chain. Does it happen primarily in just
one gear? Have you checked the chain for wear (1/16" in 12" is a useful wear limit)?

--
Ryan Cousineau, [email hidden] sfu.ca~rcousineOpen ↗ President, Fabrizio Mazzoleni Fan Club

Check each link in the chain to ensure that one or more of them isn't seized. It's one of those
litle things that will be missed except under hard pedaling such as up a hill.

skipping chain could also be caused by a twisted ring tooth or a tight link.

--
______________________________________

"It's never too late to have a happy childhood."
______________________________________
"Ryan Cousineau" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

In article said:

Maybe someone could please point me in the right technical direction as

I

Quoted message said:

Quoted message said:

just don't see anything upon inspection and I've lost trust in my bike shop technican's
expertise (long story). When pedaling uphill where the bike

has

Quoted message said:

Quoted message said:

the most load on the gears, chain, etc., I feel a clunk throughout the

drive.

Quoted message said:

Quoted message said:

Problem happens frequently but not readily repeatable. I'm sure this is

a

Quoted message said:

Quoted message said:

common problem and my question to this posting is primarily most common sources that people have
seen. Any inputs would be greatly appreciated. Thanks.

First guess is a skipping chain due to wear on the cog and chain. Does it happen primarily in just
one gear? Have you checked the chain for wear (1/16" in 12" is a useful wear limit)?

--
Ryan Cousineau, [email hidden] sfu.ca~rcousineOpen ↗ President, Fabrizio Mazzoleni Fan Club

---
Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (grisoft.comgrisoft.comOpen ↗).
Version: 6.0.456 / Virus Database: 256 - Release Date: 2/18/2003

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

Quoted message said:

Maybe someone could please point me in the right technical direction as I

just

Quoted message said:

don't see anything upon inspection and I've lost trust in my bike shop technican's expertise (long
story). When pedaling uphill where the bike

has

Quoted message said:

the most load on the gears, chain, etc., I feel a clunk throughout the

drive.

Quoted message said:

Problem happens frequently but not readily repeatable. I'm sure this is a common problem and my
question to this posting is primarily most common

sources

Quoted message said:

that people have seen. Any inputs would be greatly appreciated. Thanks.

Couldn't this be a bad bb bearing or hub bearing? I had a thunk in my bb and replaced the sealed
bearing that was shot and it works great.

Bob

Sounds more like a chain problem, check the links to see if one of them is seized. Work backwards
from there.

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

Quoted message said:

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

Quoted message said:

Maybe someone could please point me in the right technical direction as

I

Quoted message said:

just

Quoted message said:

don't see anything upon inspection and I've lost trust in my bike shop technican's expertise
(long story). When pedaling uphill where the bike

has

Quoted message said:

the most load on the gears, chain, etc., I feel a clunk throughout the

drive.

Quoted message said:

Problem happens frequently but not readily repeatable. I'm sure this is

a

Quoted message said:

Quoted message said:

common problem and my question to this posting is primarily most common

sources

Quoted message said:

that people have seen. Any inputs would be greatly appreciated. Thanks.

Couldn't this be a bad bb bearing or hub bearing? I had a thunk in my bb and replaced the sealed
bearing that was shot and it works great.

Bob

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

Quoted message said:

In article said:

Maybe someone could please point me in the right technical direction as

I

Quoted message said:

Quoted message said:

just don't see anything upon inspection and I've lost trust in my bike shop technican's
expertise (long story). When pedaling uphill where the bike

has

Quoted message said:

Quoted message said:

the most load on the gears, chain, etc., I feel a clunk throughout the

drive.

Quoted message said:

Quoted message said:

Problem happens frequently but not readily repeatable. I'm sure this is

a

Quoted message said:

Quoted message said:

common problem and my question to this posting is primarily most common sources that people have
seen. Any inputs would be greatly appreciated. Thanks.

First guess is a skipping chain due to wear on the cog and chain. Does it happen primarily in just
one gear? Have you checked the chain for wear (1/16" in 12" is a useful wear limit)?

Loose crank arms?

Shaun aRe - heh.....

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

Quoted message said:

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

Quoted message said:

In article said:

Maybe someone could please point me in the right technical direction

as

Quoted message said:

I

Quoted message said:

Quoted message said:

just don't see anything upon inspection and I've lost trust in my bike shop technican's
expertise (long story). When pedaling uphill where the

bike

Quoted message said:

has

Quoted message said:

Quoted message said:

the most load on the gears, chain, etc., I feel a clunk throughout the

drive.

Quoted message said:

Quoted message said:

Problem happens frequently but not readily repeatable. I'm sure this

is

Quoted message said:

a

Quoted message said:

Quoted message said:

common problem and my question to this posting is primarily most

common

Quoted message said:

Quoted message said:

Quoted message said:

sources that people have seen. Any inputs would be greatly appreciated.

Thanks.

Quoted message said:

Quoted message said:

First guess is a skipping chain due to wear on the cog and chain. Does it happen primarily in
just one gear? Have you checked the chain for wear (1/16" in 12" is a useful wear limit)?

Loose crank arms?

Shaun aRe - heh.....

I'm with you Shaun. Check the bb and crank arms....

Bob