Do gear springs lose their 'spring'?

AP said:

Now that I've replaced my 5-speed block with a 7-speed, my rear
shifter's having to do a bit more work, and it's not coping very well.
Shifting down is fine, but shifting up causes problems. Any shifts
between, say, the bottom (larger) three or four sprockets is fine, but
once it gets up to around 5+, it doesn't shift up when the loosening
cable 'gives it permission'...it has a little think about it, then
eventually shifts up in its own good time, which can be anything up to
10 seconds later. It gets there in the end, but it's way slow.

The whole mechanism (Record) revolves around one hefty wishbone-type
spring - that's what hauls it up the last few sprockets - is it
possible that the thing's simply got a bit fatigued (it is probably 20
years old now) and lost its springiness? Might I be able to fix it sort
of along the lines of fixing an imbalanced set of brakes by unclipping
the spring on one side and distorting it slightly to make it springier?
Or will I just end up snapping the spring?

Any suggestions much appreciated.

Alan

They do eventually lose their spring, not sure of the best solution
other than replacing the mech.

Worth checking that your cable is not gunged up as well.
--
Three wheels good, two wheels ok

www.catrike.co.uk

in message <[email hidden]>, AP

(') said:

Now that I've replaced my 5-speed block with a 7-speed, my rear shifter's
having to do a bit more work, and it's not coping very well. Shifting
down is fine, but shifting up causes problems. Any shifts between, say,
the bottom (larger) three or four sprockets is fine, but once it gets up
to around 5+, it doesn't shift up when the loosening cable 'gives it
permission'...it has a little think about it, then eventually shifts up
in its own good time, which can be anything up to 10 seconds later. It
gets there in the end, but it's way slow.

The whole mechanism (Record) revolves around one hefty wishbone-type
spring - that's what hauls it up the last few sprockets - is it possible
that the thing's simply got a bit fatigued (it is probably 20 years old
now) and lost its springiness? Might I be able to fix it sort of along
the lines of fixing an imbalanced set of brakes by unclipping the spring
on one side and distorting it slightly to make it springier? Or will I
just end up snapping the spring?

They do lose their spring, and if it's 20 years old this may be the
problem. But more often the problem is stiction in the cable run - try
replacing the cable, including all the sleeves, and cleaning out the guide
under the bottom bracket. You may be surprised how much difference this
makes. And cables are a lot cheaper than good mechs!

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/

;; I'd rather live in sybar-space

AP wrote:
.....

Quoted message said:

The whole mechanism (Record) revolves around one hefty wishbone-type
spring - that's what hauls it up the last few sprockets - is it
possible that the thing's simply got a bit fatigued (it is probably
20 years old now) and lost its springiness? Might I be able to fix it
sort of along the lines of fixing an imbalanced set of brakes by
unclipping the spring on one side and distorting it slightly to make
it springier? Or will I just end up snapping the spring?

I doubt it'll snap. It'll be worth a go if you're confident that you can
refit it. Check the cables and guides first though.

~PB

Buck said:

AP said:

Now that I've replaced my 5-speed block with a 7-speed, my rear
shifter's having to do a bit more work, and it's not coping very well.
Shifting down is fine, but shifting up causes problems. Any shifts
between, say, the bottom (larger) three or four sprockets is fine, but
once it gets up to around 5+, it doesn't shift up when the loosening
cable 'gives it permission'...it has a little think about it, then
eventually shifts up in its own good time, which can be anything up to
10 seconds later. It gets there in the end, but it's way slow.

The whole mechanism (Record) revolves around one hefty wishbone-type
spring - that's what hauls it up the last few sprockets - is it
possible that the thing's simply got a bit fatigued (it is probably 20
years old now) and lost its springiness? Might I be able to fix it sort
of along the lines of fixing an imbalanced set of brakes by unclipping
the spring on one side and distorting it slightly to make it springier?
Or will I just end up snapping the spring?

Any suggestions much appreciated.

Alan

They do eventually lose their spring, not sure of the best solution
other than replacing the mech.

No.

Time has no effect on the modulus of elasticity. (This is
beginners-level materials science).

It is instead more likely that the op's rear mech now has to travel
farther, and the geometry of the cluster and the mech is such that the
effective force available from the spring at the extreme is
sufficiently less that he has the symptoms described.

Some of the better rear mechs have had multiple spring anchor
placements to allow for such variability in cluster geometry. The op
might find or make such an adjustment, or perhaps put a spacer under
the fixing bolt.

The crudest approach is indeed that which he suggested, and were he to
attempt such, there is little danger of "snapping" the spring.

Quoted message said:

Time has no effect on the modulus of elasticity. (This is
beginners-level materials science).

Not time, but how about the amount of /use/ (and abuse)?

~PB

Thanks all. 'the modulus of elasticity' - sounds like an obscure Eastern
Potentate - 'Ambassador, may I introduce The Modulus of Elasticity'....

I'm well intrigued by this account of 'multiple spring anchor placements' on
'some of the better rear mechs'...well, it's a Super Record, so they don't
come much better - anyone know whether or not this unit has such options,
and if so, how the wee beasties can be idenitified?

And if that doesn't work, time for me Big Pliers...
<[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Buck said:

On 2007-02-07 10:55:22 +0000, "AP" <[email hidden]>

Quoted message said:

Now that I've replaced my 5-speed block with a 7-speed, my rear
shifter's having to do a bit more work, and it's not coping very well.
Shifting down is fine, but shifting up causes problems. Any shifts
between, say, the bottom (larger) three or four sprockets is fine, but
once it gets up to around 5+, it doesn't shift up when the loosening
cable 'gives it permission'...it has a little think about it, then
eventually shifts up in its own good time, which can be anything up to
10 seconds later. It gets there in the end, but it's way slow.

The whole mechanism (Record) revolves around one hefty wishbone-type
spring - that's what hauls it up the last few sprockets - is it
possible that the thing's simply got a bit fatigued (it is probably 20
years old now) and lost its springiness? Might I be able to fix it sort
of along the lines of fixing an imbalanced set of brakes by unclipping
the spring on one side and distorting it slightly to make it springier?
Or will I just end up snapping the spring?

Any suggestions much appreciated.

Alan

They do eventually lose their spring, not sure of the best solution
other than replacing the mech.

No.

Time has no effect on the modulus of elasticity. (This is
beginners-level materials science).

It is instead more likely that the op's rear mech now has to travel
farther, and the geometry of the cluster and the mech is such that the
effective force available from the spring at the extreme is
sufficiently less that he has the symptoms described.

Some of the better rear mechs have had multiple spring anchor
placements to allow for such variability in cluster geometry. The op
might find or make such an adjustment, or perhaps put a spacer under
the fixing bolt.

The crudest approach is indeed that which he suggested, and were he to
attempt such, there is little danger of "snapping" the spring.

Simon Brooke said:

in message <[email hidden]>, AP

....

Quoted message said:

They do lose their spring, and if it's 20 years old this may be the
problem. But more often the problem is stiction in the cable run - try
replacing the cable, including all the sleeves, and cleaning out the guide
under the bottom bracket. You may be surprised how much difference this
makes. And cables are a lot cheaper than good mechs!

I'd also make sure all the pivots on the mech itself are completely
clean and well lubricated. A small amount of friction in the mech
movement itself could easily give the effect described (and has for me
on numerous previous occasions - clean the bike? when I can go and
ride it???)

TL

Quoted message said:

Time has no effect on the modulus of elasticity. (This is
beginners-level materials science).

Quite right, time in and of itself does not affect the modulus of
elasticity but several thousand cycles of the spring in that time will.
Consider "work hardening", is that not involved in changing the
modulus of elasticity?

soup said:

Quoted message said:

Time has no effect on the modulus of elasticity. (This is
beginners-level materials science).

Quite right, time in and of itself does not affect the modulus of
elasticity but several thousand cycles of the spring in that time will.
Consider "work hardening", is that not involved in changing the modulus
of elasticity?

I'm afraid not. Work hardening changes the ultimate strength of the
metal, but not the mod of elasticity. If you look at the modulus and
strength of a wide range of steels with different tempers you'll find
that the mod of elasticity (maybe we should just write stiffness if this
goes on!) varies hardly at all while strength varies over a wide range.

--
Roger Thorpe

My email address is spamtrapped. You can work it out!

Quoted message said:

Buck said:

AP said:

Now that I've replaced my 5-speed block with a 7-speed, my rear
shifter's having to do a bit more work, and it's not coping very well.
Shifting down is fine, but shifting up causes problems. Any shifts
between, say, the bottom (larger) three or four sprockets is fine, but
once it gets up to around 5+, it doesn't shift up when the loosening
cable 'gives it permission'...it has a little think about it, then
eventually shifts up in its own good time, which can be anything up to
10 seconds later. It gets there in the end, but it's way slow.

The whole mechanism (Record) revolves around one hefty wishbone-type
spring - that's what hauls it up the last few sprockets - is it
possible that the thing's simply got a bit fatigued (it is probably 20
years old now) and lost its springiness? Might I be able to fix it sort
of along the lines of fixing an imbalanced set of brakes by unclipping
the spring on one side and distorting it slightly to make it springier?
Or will I just end up snapping the spring?

Any suggestions much appreciated.

Alan

They do eventually lose their spring, not sure of the best solution
other than replacing the mech.

No.

Time has no effect on the modulus of elasticity. (This is
beginners-level materials science).

Wrong, the spring is subject to cyclic loading and is made from a tempered
material, the associated stresses of loading and unlading the spring will
ultimately mean that the effects of tempering the material will be lost
over time.

The correct way to treat this is to anneal the material and then re-temper it.

This was probably not covered in your beginners level material science course.

Quoted message said:

The crudest approach is indeed that which he suggested, and were he to
attempt such, there is little danger of "snapping" the spring.

If the tempering has been lost then all that will happen is that the
spring will
soon return to the position it was in pre-bending.

--
Three wheels good, two wheels ok

www.catrike.co.uk

Buck said:

Quoted message said:

Buck said:

On 2007-02-07 10:55:22 +0000, "AP"
<[email hidden]> said:

> Now that I've replaced my 5-speed block with a 7-speed, my rear
> shifter's having to do a bit more work, and it's not coping very
> well. Shifting down is fine, but shifting up causes problems. Any
> shifts between, say, the bottom (larger) three or four sprockets is
> fine, but once it gets up to around 5+, it doesn't shift up when the
> loosening cable 'gives it permission'...it has a little think about
> it, then eventually shifts up in its own good time, which can be
> anything up to 10 seconds later. It gets there in the end, but it's
> way slow.
>
> The whole mechanism (Record) revolves around one hefty wishbone-type
> spring - that's what hauls it up the last few sprockets - is it
> possible that the thing's simply got a bit fatigued (it is probably
> 20 years old now) and lost its springiness? Might I be able to fix
> it sort of along the lines of fixing an imbalanced set of brakes by
> unclipping the spring on one side and distorting it slightly to make
> it springier? Or will I just end up snapping the spring?
>
> Any suggestions much appreciated.
>
> Alan

They do eventually lose their spring, not sure of the best solution
other than replacing the mech.

No.

Time has no effect on the modulus of elasticity. (This is
beginners-level materials science).

Wrong, the spring is subject to cyclic loading and is made from a tempered
material, the associated stresses of loading and unlading the spring will
ultimately mean that the effects of tempering the material will be lost
over time.

The correct way to treat this is to anneal the material and then
re-temper it.

This was probably not covered in your beginners level material science
course.

Quoted message said:

The crudest approach is indeed that which he suggested, and were he to
attempt such, there is little danger of "snapping" the spring.

If the tempering has been lost then all that will happen is that the
spring will
soon return to the position it was in pre-bending.

Can I just step in here? Because in a sense you're both right. Temper
(and within reasonable limits carbon content) will not change the
modulus of elasticity, What it will do is to change the elastic limit
where any deformation becomes permanent.
I'm not sure that any material will work-soften mind you...

I think the poster who mentioned the cable friction got this one about
right.
Roger
--
Roger Thorpe

My email address is spamtrapped. You can work it out!

Roger Thorpe said:

Buck said:

Quoted message said:

On Wed, 07 Feb 2007 11:05:36 GMT, Buck
<[email hidden]> wrote:

> On 2007-02-07 10:55:22 +0000, "AP" <[email hidden]> said:
>
>> Now that I've replaced my 5-speed block with a 7-speed, my rear
>> shifter's having to do a bit more work, and it's not coping very well.
>> Shifting down is fine, but shifting up causes problems. Any shifts
>> between, say, the bottom (larger) three or four sprockets is fine, but
>> once it gets up to around 5+, it doesn't shift up when the loosening
>> cable 'gives it permission'...it has a little think about it, then
>> eventually shifts up in its own good time, which can be anything up to
>> 10 seconds later. It gets there in the end, but it's way slow.
>>
>> The whole mechanism (Record) revolves around one hefty wishbone-type
>> spring - that's what hauls it up the last few sprockets - is it
>> possible that the thing's simply got a bit fatigued (it is probably 20
>> years old now) and lost its springiness? Might I be able to fix it sort
>> of along the lines of fixing an imbalanced set of brakes by unclipping
>> the spring on one side and distorting it slightly to make it springier?
>> Or will I just end up snapping the spring?
>>
>> Any suggestions much appreciated.
>>
>> Alan
>
>
> They do eventually lose their spring, not sure of the best solution
> other than replacing the mech.
>

No.

Time has no effect on the modulus of elasticity. (This is
beginners-level materials science).

Wrong, the spring is subject to cyclic loading and is made from a tempered
material, the associated stresses of loading and unlading the spring will
ultimately mean that the effects of tempering the material will be lost
over time.

The correct way to treat this is to anneal the material and then re-temper it.

This was probably not covered in your beginners level material science course.

Quoted message said:

The crudest approach is indeed that which he suggested, and were he to
attempt such, there is little danger of "snapping" the spring.

If the tempering has been lost then all that will happen is that the
spring will
soon return to the position it was in pre-bending.

Can I just step in here? Because in a sense you're both right. Temper
(and within reasonable limits carbon content) will not change the
modulus of elasticity, What it will do is to change the elastic limit
where any deformation becomes permanent.
I'm not sure that any material will work-soften mind you...

I think the poster who mentioned the cable friction got this one about right.
Roger

I mentioned that in my original answer to.

In my experience a spring subject to frequent cyclic loading and unloading
will lose it's tempering.
--
Three wheels good, two wheels ok

www.catrike.co.uk

Pete Biggs said:

Quoted message said:

Time has no effect on the modulus of elasticity. (This is
beginners-level materials science).

Not time, but how about the amount of /use/ (and abuse)?

Zero effect.

Buck said:

Quoted message said:

Buck said:

On 2007-02-07 10:55:22 +0000, "AP" <[email hidden]> said:

> Now that I've replaced my 5-speed block with a 7-speed, my rear
> shifter's having to do a bit more work, and it's not coping very well.
> Shifting down is fine, but shifting up causes problems. Any shifts
> between, say, the bottom (larger) three or four sprockets is fine, but
> once it gets up to around 5+, it doesn't shift up when the loosening
> cable 'gives it permission'...it has a little think about it, then
> eventually shifts up in its own good time, which can be anything up to
> 10 seconds later. It gets there in the end, but it's way slow.
>
> The whole mechanism (Record) revolves around one hefty wishbone-type
> spring - that's what hauls it up the last few sprockets - is it
> possible that the thing's simply got a bit fatigued (it is probably 20
> years old now) and lost its springiness? Might I be able to fix it sort
> of along the lines of fixing an imbalanced set of brakes by unclipping
> the spring on one side and distorting it slightly to make it springier?
> Or will I just end up snapping the spring?
>
> Any suggestions much appreciated.
>
> Alan

They do eventually lose their spring, not sure of the best solution
other than replacing the mech.

No.

Time has no effect on the modulus of elasticity. (This is
beginners-level materials science).

Wrong, the spring is subject to cyclic loading and is made from a tempered
material, the associated stresses of loading and unlading the spring will
ultimately mean that the effects of tempering the material will be lost
over time.

The correct way to treat this is to anneal the material and then re-temper it.

This was probably not covered in your beginners level material science course.

Quoted message said:

And what change in the modulus of elasticity do you claim will result
from any such work hardening and/or tempering?

Buck said:

Roger Thorpe said:

Buck said:

On 2007-02-07 13:31:27 +0000, [email hidden] said:

> On Wed, 07 Feb 2007 11:05:36 GMT, Buck
> <[email hidden]> wrote:
>
>> On 2007-02-07 10:55:22 +0000, "AP" <[email hidden]> said:
>>
>>> Now that I've replaced my 5-speed block with a 7-speed, my rear
>>> shifter's having to do a bit more work, and it's not coping very well.
>>> Shifting down is fine, but shifting up causes problems. Any shifts
>>> between, say, the bottom (larger) three or four sprockets is fine, but
>>> once it gets up to around 5+, it doesn't shift up when the loosening
>>> cable 'gives it permission'...it has a little think about it, then
>>> eventually shifts up in its own good time, which can be anything up to
>>> 10 seconds later. It gets there in the end, but it's way slow.
>>>
>>> The whole mechanism (Record) revolves around one hefty wishbone-type
>>> spring - that's what hauls it up the last few sprockets - is it
>>> possible that the thing's simply got a bit fatigued (it is probably 20
>>> years old now) and lost its springiness? Might I be able to fix it sort
>>> of along the lines of fixing an imbalanced set of brakes by unclipping
>>> the spring on one side and distorting it slightly to make it springier?
>>> Or will I just end up snapping the spring?
>>>
>>> Any suggestions much appreciated.
>>>
>>> Alan
>>
>>
>> They do eventually lose their spring, not sure of the best solution
>> other than replacing the mech.
>>
>
> No.
>
> Time has no effect on the modulus of elasticity. (This is
> beginners-level materials science).

Wrong, the spring is subject to cyclic loading and is made from a tempered
material, the associated stresses of loading and unlading the spring will
ultimately mean that the effects of tempering the material will be lost
over time.

The correct way to treat this is to anneal the material and then re-temper it.

This was probably not covered in your beginners level material science course.

>
> The crudest approach is indeed that which he suggested, and were he to
> attempt such, there is little danger of "snapping" the spring.

If the tempering has been lost then all that will happen is that the
spring will
soon return to the position it was in pre-bending.

Can I just step in here? Because in a sense you're both right. Temper
(and within reasonable limits carbon content) will not change the
modulus of elasticity, What it will do is to change the elastic limit
where any deformation becomes permanent.
I'm not sure that any material will work-soften mind you...

I think the poster who mentioned the cable friction got this one about right.
Roger

I mentioned that in my original answer to.

In my experience a spring subject to frequent cyclic loading and unloading
will lose it's tempering.

And why do you think any such change has any effect on the modulus of
elasticity?

AP said:

Thanks all. 'the modulus of elasticity' - sounds like an obscure Eastern
Potentate - 'Ambassador, may I introduce The Modulus of Elasticity'....

I'm well intrigued by this account of 'multiple spring anchor placements' on
'some of the better rear mechs'...well, it's a Super Record, so they don't
come much better - anyone know whether or not this unit has such options,
and if so, how the wee beasties can be idenitified?

And if that doesn't work, time for me Big Pliers...
<[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Buck said:

On 2007-02-07 10:55:22 +0000, "AP" <[email hidden]>
said:

Quoted message said:

Quoted message said:

Quoted message said:

They do eventually lose their spring, not sure of the best solution
other than replacing the mech.

No.

Time has no effect on the modulus of elasticity. (This is
beginners-level materials science).

It is instead more likely that the op's rear mech now has to travel
farther, and the geometry of the cluster and the mech is such that the
effective force available from the spring at the extreme is
sufficiently less that he has the symptoms described.

Some of the better rear mechs have had multiple spring anchor
placements to allow for such variability in cluster geometry. The op
might find or make such an adjustment, or perhaps put a spacer under
the fixing bolt.

a) please don't top-post;

b) Huret.

Quoted message said:

Quoted message said:

And why do you think any such change has any effect on the modulus of
elasticity?

Yeah I noticed you went off topic, we were discussing a spring, you were in
your own little world.

--
Three wheels good, two wheels ok

www.catrike.co.uk

Quoted message said:

Buck said:

Quoted message said:

On Wed, 07 Feb 2007 11:05:36 GMT, Buck
<[email hidden]> wrote:

> On 2007-02-07 10:55:22 +0000, "AP" <[email hidden]> said:
>
>> Now that I've replaced my 5-speed block with a 7-speed, my rear
>> shifter's having to do a bit more work, and it's not coping very well.
>> Shifting down is fine, but shifting up causes problems. Any shifts
>> between, say, the bottom (larger) three or four sprockets is fine, but
>> once it gets up to around 5+, it doesn't shift up when the loosening
>> cable 'gives it permission'...it has a little think about it, then
>> eventually shifts up in its own good time, which can be anything up to
>> 10 seconds later. It gets there in the end, but it's way slow.
>>
>> The whole mechanism (Record) revolves around one hefty wishbone-type
>> spring - that's what hauls it up the last few sprockets - is it
>> possible that the thing's simply got a bit fatigued (it is probably 20
>> years old now) and lost its springiness? Might I be able to fix it sort
>> of along the lines of fixing an imbalanced set of brakes by unclipping
>> the spring on one side and distorting it slightly to make it springier?
>> Or will I just end up snapping the spring?
>>
>> Any suggestions much appreciated.
>>
>> Alan
>
> They do eventually lose their spring, not sure of the best solution
> other than replacing the mech.
>

No.

Time has no effect on the modulus of elasticity. (This is
beginners-level materials science).

Wrong, the spring is subject to cyclic loading and is made from a tempered
material, the associated stresses of loading and unlading the spring will
ultimately mean that the effects of tempering the material will be lost
over time.

The correct way to treat this is to anneal the material and then re-temper it.

This was probably not covered in your beginners level material science course.

Quoted message said:

And what change in the modulus of elasticity do you claim will result
from any such work hardening and/or tempering?

Try staying on topic.
--
Three wheels good, two wheels ok

www.catrike.co.uk

soup said:

Quoted message said:

Time has no effect on the modulus of elasticity. (This is
beginners-level materials science).

Quite right, time in and of itself does not affect the modulus of
elasticity but several thousand cycles of the spring in that time will.
Consider "work hardening", is that not involved in changing the
modulus of elasticity?

No.

It's a common beginner error to think that harder steels, (whether
harder through composition or though heat-treatment) are 'stiffer" or
"springier", but it is not true.