Deraileur noise

[Per LöWdin]

Hi

I just changed my wrecked short cage xtr deraileur for a long cage and get an evil noise when it is
running on the smallest chain ring and largest cassett sprocket 34T. B-screw is tightened. Should I
have added two chain links to accomodate the long cage deraileur? Or might it be something else?
Poor adjustment? Bent hanger?

Per http://user.tninet.se/~ipg289h/English.html

 

[Jobst Brandt]

Per Löwdin writes:

> I just changed my wrecked short cage XTR derailleur for a long cage and get an evil noise when it
> is running on the smallest chain ring and largest cassette sprocket 34T. B-screw is tightened.
> Should I have added two chain links to accommodate the long cage derailleur? Or might it be
> something else? Poor adjustment? Bent hanger?

Watch the chain go past the rear sprockets and derailleur when sitting beside the bicycle and
turning the pedals backwards. It sounds as though you need more chain length and the upper
derailleur idler is interfering with the sprocket. On the other hand, the destruction of your
previous derailleur may have bent the dropout but that should cause problems in other gears as well.

If you add chain, make sure to check its run on the small sprocket... at least in the combinations
that you foresee needing. Not all ratios theoretically possible are reasonable, such as largest to
largest, so don't worry about those.

Jobst Brandt [email protected] Palo Alto CA

 

[Per LöWdin]

<[email protected]> skrev i meddelandet
news:[email protected]...

> Watch the chain go past the rear sprockets and derailleur when sitting beside the bicycle and
> turning the pedals backwards. It sounds as though you need more chain length and the upper
> derailleur idler is interfering with the sprocket. On the other hand, the destruction of your
> previous derailleur may have bent the dropout but that should cause problems in other gears
> as well.

Thanks, actually i was destroyed because I put on a short cage when there should have been a long
cage, to handle a 34 t cassette. I just might take it to a shop that has the tools to straighten the
dropout. Does not take much to make it shift badly

Per

 

[David Kunz]

Per Löwdin wrote:
> Hi
>
> I just changed my wrecked short cage xtr deraileur for a long cage and get an evil noise when it
> is running on the smallest chain ring and largest cassett sprocket 34T. B-screw is tightened.
> Should I have added two chain links to accomodate the long cage deraileur? Or might it be
> something else? Poor adjustment? Bent hanger?

First thing is to check the B adjustment screw. This pulls the cage away from the cassette and
should be adjusted so that the DR cage gears are not in contact with the cassette in that
combination -- make sure that your bike is upright when you do this test (not upside down) -- it
does make a difference. If you need more adjustment, some recommend turning the screw around, but
I'd take it to a good HW store and just get a longer one (in stainless or hardened so you don't have
rust problems ).

Then, check your chain length. The rule of thumb that works for me is to thread put the chain
outside the rear DR in the Big-Big combination and add 1 link (that's 2 pieces). I've found that on
my bike, I only add 1/2 link -- 1-1/2 is too much for decent shifing while in the small
CR. After that, thread the chain properly and make sure that it will shift into the Big-Big
combination without damaging the DR -- from both the front and the back. This is not a gear
combination that you'd normally use, but you want to make sure that if you use it accidentally
you don't damage your DR or hanger (I end up in this combination at night sometimes -- when I
can't see the gear indicators and lose track).

David

 

[Qui Si Parla Ca]

perlowdin-<< Should I have added two chain links to accomodate the long cage deraileur? Or might it
be something else? Poor adjustment? Bent hanger?

'Hold the der real close to the computer, make the noise'...tough to say w/o hearing it but it
may be the b limit altho if the chain length is the same with the short cage to the long,
shouldn't be that.

Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
(303)440-3535 http://www.vecchios.com "Ruote convenzionali costruite eccezionalmente bene"

 

[Per LöWdin]

"David Kunz" <[email protected]> wrote :

> First thing is to check the B adjustment screw. This pulls the cage away from the cassette and
> should be adjusted so that the DR cage gears are not in contact with the cassette in that
> combination -- make sure that your bike is upright when you do this test (not upside down) -- it
> does make a difference. If you need more adjustment, some recommend turning the screw around, but
> I'd take it to a good HW store and just get a longer one (in stainless or hardened so you don't
> have rust problems ).

Funny thing is I don´t think it is the B-screw. When I backpedal it is spinning fine, without noise,
without rubbing, it even does when I pedal forward, it is when the chain gets heavily loades: e.g.,
climbing up something that it gets some kind of mega chain suck, makes an evil rubbing noise, and
would, if I was not be so keen on avoiding it pull the deraileur into the spokes or worse..

>
> Then, check your chain length. The rule of thumb that works for me is to thread put the chain
> outside the rear DR in the Big-Big combination and add 1 link (that's 2 pieces). I've found that
> on my bike, I only add 1/2 link
- ???

> CR. After that, thread the chain properly and make sure that it will shift into the Big-Big
> combination without damaging the DR -- from both the front and the back. This is not a gear
> combination that you'd normally use, but you want to make sure that if you use it
> accidentally you don't damage your DR or hanger (I end up in this combination at night
> sometimes -- when I can't see the gear indicators and lose track).

I do too, even though I try to keep track of the gears (at least sufficiently for that not to
happen) but then I forget and when I come out in street light i realise I been going on the big
small combination without realising. Per

 

[Per LöWdin]

"Qui si parla Campagnolo" wrote:
> perlowdin-<< Should I have added two chain links to accomodate the long cage deraileur? Or might
> it be something
else?
> Poor adjustment? Bent hanger?
>
> 'Hold the der real close to the computer, make the noise'...tough to say
w/o
> hearing it but it may be the b limit altho if the chain length is the same
with
> the short cage to the long, shouldn't be that.

Peter are you saying that the chainlength should be "constant": i.e., that it should be the same
regardless of whether you have a short or long cage deraileur? Grateful for any comments on that.

Per

 

[David Kunz]

Per Löwdin wrote:
> "David Kunz" <[email protected]> wrote :
>
>
>>First thing is to check the B adjustment screw. This pulls the cage away from the cassette and
>>should be adjusted so that the DR cage gears are not in contact with the cassette in that
>>combination -- make sure that your bike is upright when you do this test (not upside down) -- it
>>does make a difference. If you need more adjustment, some recommend turning the screw around, but
>>I'd take it to a good HW store and just get a longer one (in stainless or hardened so you don't
>>have rust problems ).
>
>
> Funny thing is I don´t think it is the B-screw. When I backpedal it is spinning fine, without
> noise, without rubbing, it even does when I pedal forward, it is when the chain gets heavily
> loades: e.g., climbing up something that it gets some kind of mega chain suck, makes an evil
> rubbing noise, and would, if I was not be so keen on avoiding it pull the deraileur into the
> spokes or worse..

Backward and forward pedaling will make a difference in the way the chain is loaded. I don't think
that it'll backpedal provides any info.

Under load pulls the chain really tight -- are you sure that it's not rubbing the front DR
shifting cage? Are you sure that you don't have a tight link in the chain or that the chain is not
a 9-speed chain?

>>Then, check your chain length. The rule of thumb that works for me is to thread put the chain
>>outside the rear DR in the Big-Big combination and add 1 link (that's 2 pieces). I've found that
>>on my bike, I only add 1/2 link
>
> - ???

Take the chain off. Thread it around the big-big combination through the front DR but not through
the back DR. Your chain should be about 1-full link longer then this. A link is 2 chain pieces. My
choice is either 1/2 link (one piece) or 1-1/2 link (3 pieces) longer than this (you can't put half
a link on ). What I meant by 1/2 link is that I've found that if my chain is only 1/2 link (one
chain piece) longer than this, it's tight on the big-big combination, but will shift in and out of
it when I accidentally do that. But, with 1-1/2 link margin the chain is too loose to use the small
CR with any cassette gear beyond the 5th.

David ...
>
>>CR. After that, thread the chain properly and make sure that it will shift into the Big-Big
>> combination without damaging the DR -- from both the front and the back. This is not a gear
>> combination that you'd normally use, but you want to make sure that if you use it
>> accidentally you don't damage your DR or hanger (I end up in this combination at night
>> sometimes -- when I can't see the gear indicators and lose track).
>
>
> I do too, even though I try to keep track of the gears (at least sufficiently for that not to
> happen) but then I forget and when I come out in street light i realise I been going on the big
> small combination without realising. Per

 

[Per LöWdin]

> Under load pulls the chain really tight -- are you sure that it's not rubbing the front DR
> shifting cage?

Yes.

> Are you sure that you don't have a tight link in the chain

Yes.

> or that the chain is not a 9-speed chain?

Yes, it is brand new Duraace chain.

I compared it to the Parktool http://www.parktool.com/repair_help/FAQchainlength.shtml images and
the chain is really stretching out the deraileur. Runs almost straight through it on the
big-big-combo so I think it might be that. A longer cage should take more chain. I think I´ll try
with adding two links. Though I hate breaking a new chain. Can´t figure out how you join a half link
(or one link) to the chain? Am I missunderstanding you?

Per

 

[Jobst Brandt]

Benjamin Lewis writes:

> I imagine such special links are not useful on bicycles... unless perhaps one wanted to build a
> single speed with vertical dropouts.

Even a half link will not a fixed gear make. Chain slack runs in less than 1/16" and a half link
will make a 1/4" change. Hitting the right chain length by accident is possible but not probable. I
once had a derailleur break in half on a trail and was fortunate to have the right length for 50-15
and 46-20 after removing the broken parts and a few links.

Jobst Brandt [email protected] Palo Alto CA