Chain problem: Twisted Link?

LF said:

Wreckmates,

My son rides his MTB pretty hard, and I do my best to fix it. Last
week he complained of transmission problems. I found a twisted link
in the chain, and replaced it with a brand new chain. The problem
returned. Today, I again found a twisted link.

<http://tinypic.com/view.php?pic=4ku3jo8>
or
<>

See an above link for a picture.

Is this probably caused by the dreaded small front chainring / small
rear cog combo, or might there be another cause.

Thanks for you thoughts.

Best,
Larry

A lot of people, especially kids (I know from experience), shift under
load. Modern stuff will let you get away with it some of the time, but
it's really not necessary and will get you into trouble eventually.

LF said:

Wreckmates,

My son rides his MTB pretty hard, and I do my best to fix it. Last
week he complained of transmission problems. I found a twisted link
in the chain, and replaced it with a brand new chain. The problem
returned. Today, I again found a twisted link.

<http://tinypic.com/view.php?pic=4ku3jo8>
or
<>

See an above link for a picture.

Is this probably caused by the dreaded small front chainring / small
rear cog combo, or might there be another cause.

Thanks for you thoughts.

Best,
Larry

I don't think it's possible for riding in cross gears to have anything
to do with this. Most likely something is happeneing every once in a
while where the chain gets jammed. This could either be derailing in
front or back and getting caught somewhere, or getting caught in the
front derailer due to an error in it's height or angle adjustment. I
know I've seen the latter cause this at least once. When it happens,
it may sound/feel like a shift gone horribly wrong, and then maybe
start working.

"LF" <[email hidden]> wrote in message
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Quoted message said:

Wreckmates,

My son rides his MTB pretty hard, and I do my best to fix it. Last
week he complained of transmission problems. I found a twisted link
in the chain, and replaced it with a brand new chain. The problem
returned. Today, I again found a twisted link.

<http://tinypic.com/view.php?pic=4ku3jo8>
or
<>

See an above link for a picture.

Is this probably caused by the dreaded small front chainring / small
rear cog combo, or might there be another cause.

Thanks for you thoughts.

Best,
Larry

That's exactly what happened to me several weeks ago, same kind of twist
in the chain.

I had a new SRAM PC-58 chain, new FSA chainrings and a new Shimano
Uniglide (pre Hyperglide) cassette that has twisted teeth for easier
shifting.

I experimented with different chains and cassettes before I found the
problem. The upper derailleur pulley was severely worn allowing it to rock
side to side. I replaced the jockey wheels and now it shifts great.

Does you son's bike have an older freewheel or cassette with twisted
teeth?

Chas.