Shimano LX B-Tension Adjustment: Need Heavier Spring?

[HKEK]

The jockey pulley on my hardtail is riding against the 2 largest cogs.
It appears that there is insufficient spring tension even with the
B-screw adjusted fully in. The chain length seems right and there is
little force on the derailleur from the cable (it is the very flexible
IRD metawire).

After reading a number of posts to this group, I tried some of the
suggestions including a longer screw. None seemed to help. Manually
rotating the derailleur indicates that there is more than ample range
of motion available; however, it appears that the spring is simply too
weak.

Is the spring replaceable and is there a spring available that has a
higher spring rate? Is it possible to remove the spring and re-install
it with an extra turn or two to increase the preload?

The derailleur is a Shimano LX special edition that was only avaible
in a black and gold finish. The cassette is an XT with a 34 tooth cog.

Thanks in advance for your help.

 

[Richard Tack]

HKEK wrote:

> The jockey pulley on my hardtail is riding against the 2 largest cogs.
> It appears that there is insufficient spring tension even with the
> B-screw adjusted fully in. The chain length seems right and there is
> little force on the derailleur from the cable (it is the very flexible
> IRD metawire).
>
> After reading a number of posts to this group, I tried some of the
> suggestions including a longer screw. None seemed to help. Manually
> rotating the derailleur indicates that there is more than ample range
> of motion available; however, it appears that the spring is simply too
> weak.
>
> Is the spring replaceable and is there a spring available that has a
> higher spring rate? Is it possible to remove the spring and re-install
> it with an extra turn or two to increase the preload?
>
> The derailleur is a Shimano LX special edition that was only avaible
> in a black and gold finish. The cassette is an XT with a 34 tooth cog.
>
> Thanks in advance for your help.

Sounds like the der cage is not long enough or the chain is
too long.

 

[HKEK]

Might be. I know the XT is available in different lengths, I can't say
the same for the LX. Perhaps I should just upgrade.

 

[HKEK]

Shimano claims that the LX derailleur is compatible with a 34 tooth cassette!

 

[dianne_1234]

On 26 Oct 2004 17:30:57 -0700, [email protected] (HKEK) wrote:

>The jockey pulley on my hardtail is riding against the 2 largest cogs.
>It appears that there is insufficient spring tension even with the
>B-screw adjusted fully in. The chain length seems right and there is
>little force on the derailleur from the cable (it is the very flexible
>IRD metawire).
>
>After reading a number of posts to this group, I tried some of the
>suggestions including a longer screw. None seemed to help. Manually
>rotating the derailleur indicates that there is more than ample range
>of motion available; however, it appears that the spring is simply too
>weak.
>
>Is the spring replaceable and is there a spring available that has a
>higher spring rate? Is it possible to remove the spring and re-install
>it with an extra turn or two to increase the preload?
>
>The derailleur is a Shimano LX special edition that was only avaible
>in a black and gold finish. The cassette is an XT with a 34 tooth cog.
>
>Thanks in advance for your help.

I've solved a similar problem (on an old 105 rear derailleur) by
reducing the A-tension.

In this exploded view,
http://www.shimano-europe.com/cycling/phpimages/product/exp_view/RD_M570.pdf
I installed the spring (number 10 in the image) and installed it in a
different hole in the cage (number 11).