Front shifter fails after replacing crankset

Daniel Kelly \(AKA Jack\) said:

Hi,

I've just upgraded my crankset and bottom bracket. And now I can't change
gears on the front derailleur. I've tried moving and adjusting the front
derailleur.

I think the problem may have 2 causes:

1) I have an old, worn, 8-speed chain. The crankset is 9-speed. The
8-speed&9-speed combo shouldn't be a problem but I suspect the old chain
might be too worn to work. My worry is that although people did tell me
that shifting performance would be 'poor', they didn't say the performance
would be non-existent. Since upgrading, it's actually impossible to
controllably change gear, even if I push the derailleur way out. It's
possible to change from the large to the middle but impossible to go from
middle to large.

2) Before buying the BB and crankset, I read that the crankset needs the
longest available BB axel, so I got 121mm BB. But perhaps this is a little
too long, resulting in the front chainwheels being pushed too far away from
the frame?

My new BB is the Shimano LX Splined ES51 and the Crankset is the LX Splined
9sp M571 170mm 22.32.44

I've taken some photos to illustrate my problem:

http://www.xlk.org.uk/forum/modules.php?set_albumName=Gear_problems&op=modload&name=gallery&file=index&include=view_album.php

Thanks in advance for your help,
Jack

Looking at pictures 5, 6 and 7, your front derailleur is positioned
very high, far away from the chainrings. It's going to be hard to get
clean shifting with it so high.

http://www.sheldonbrown.com/derailer-adjustment.html#front

You might start from scratch and follow these steps one by one.

Daniel Kelly (AKA Jack) said:

I've just upgraded my crankset and bottom bracket. And now I can't

change

Quoted message said:

gears on the front derailleur. I've tried moving and adjusting the front
derailleur.

[snip]

Quoted message said:

2) Before buying the BB and crankset, I read that the crankset needs the
longest available BB axel, so I got 121mm BB.

Bingo, there's your problem!

Quoted message said:

But perhaps this is a little
too long, resulting in the front chainwheels being pushed too far

away from

Quoted message said:

the frame?

Right.

Quoted message said:

My new BB is the Shimano LX Splined ES51 and the Crankset is the LX

Splined

Quoted message said:

9sp M571 170mm 22.32.44

See: http://sheldonbrown.com/bbsize.html#deore

Your cranks _should_ have a 113 mm spindle, if the bike has a
normal-sized seat tube, 118 only if it has a fat seat tube. (Fat seat
tubes place the front derailer mechanism farther outboard.)

Sheldon "Chainline" Brown
+---------------------------------------------------+
| Time shouldn't just pass; things should happen. |
| --Harry Turtledove |
+---------------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

Hi Sheldon,

Thanks loads for your reply.

I'm not sure if I have a "fat seat tube". My bike is a 2002 Trek 4300 - the
specs claim the bike has an 'oversized Alpha aluminium' frame with
'oversized powertubes'. The full specs are here:
http://www.trekbikes.com/bikes/2002/mountain/4300.html#

Also, I'm a little worried about getting a smaller BB because the left crank
is only a mm or so away from the BB housing on my 121mm BB. If I swap my
121mm BB for a 118 mm BB, will those 3mm be lost from both sides of the axel
(i.e. bringing both the left and right cranks 1.5mm closer to the BB) or
just from the right side of the axel (i.e. the left crank position will be
exactly the same on both the 121 and 118mm BBs but the right crank will be
3mm closer)?

Thanks,
Jack

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

Quoted message said:

Daniel Kelly (AKA Jack) said:

I've just upgraded my crankset and bottom bracket. And now I can't

change

Quoted message said:

gears on the front derailleur. I've tried moving and adjusting the

front

Quoted message said:

Quoted message said:

derailleur.

[snip]

Quoted message said:

2) Before buying the BB and crankset, I read that the crankset needs

the

Quoted message said:

Quoted message said:

longest available BB axel, so I got 121mm BB.

Bingo, there's your problem!

Quoted message said:

But perhaps this is a little
too long, resulting in the front chainwheels being pushed too far

away from

Quoted message said:

the frame?

Right.

Quoted message said:

My new BB is the Shimano LX Splined ES51 and the Crankset is the LX

Splined

Quoted message said:

9sp M571 170mm 22.32.44

See: http://sheldonbrown.com/bbsize.html#deore

Your cranks _should_ have a 113 mm spindle, if the bike has a
normal-sized seat tube, 118 only if it has a fat seat tube. (Fat seat
tubes place the front derailer mechanism farther outboard.)

Sheldon "Chainline" Brown
+---------------------------------------------------+
| Time shouldn't just pass; things should happen. |
| --Harry Turtledove |
+---------------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

Quoted message said:

See: http://sheldonbrown.com/bbsize.html#deore

Sheldon "Chainline" Brown
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

Thank you Mr. Brown. Your website link confirmed my measurement of my
bottom bracket. I have a 1991 Deore DX crankset and am going to
replace the original Tange loose ball and locknut bottom bracket with
Shimano's cheap sealed unit. I had measured the original bottom
bracket and came up with about 124mm so I figured the 122mm was the
right length. But its good to have confirmation.

Daniel Kelly \(AKA Jack\) said:

Hi Sheldon,

Thanks loads for your reply.

I'm not sure if I have a "fat seat tube". My bike is a 2002 Trek 4300 - the
specs claim the bike has an 'oversized Alpha aluminium' frame with
'oversized powertubes'. The full specs are here:
http://www.trekbikes.com/bikes/2002/mountain/4300.html#

Also, I'm a little worried about getting a smaller BB because the left crank
is only a mm or so away from the BB housing on my 121mm BB. If I swap my
121mm BB for a 118 mm BB, will those 3mm be lost from both sides of the axel
(i.e. bringing both the left and right cranks 1.5mm closer to the BB) or
just from the right side of the axel (i.e. the left crank position will be
exactly the same on both the 121 and 118mm BBs but the right crank will be
3mm closer)?

There may be another fudge factor to look at. I've noted that some
Shimano BB units have about 2mm of unthreaded boss between the threads
and the right flange on the body; when torqued as per spec into a BB
shell that is threaded all the way out, the flange may not seat
against the shell as a result. If there is a gap between the flange
and the BB shell in your installation, you've run aground on this
problem. This has happened to me twice; I've swapped to using generic
BBs for the moment to get around it. The generics are uniformly
threaded all the way to the flange.

--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Surrealism is a pectinated ranzel.

I agree with Sheldon the BB is to wide .I have a 68*113 bb for cheep if you
want it.I went to a issis cranks so this is a extra from when I used a XT on
my hard tail.

Hi Werehatrack,

Thanks for the reply. No, my BB flanges are seated hard against the frame.

Thanks for the advice though.

I don't suppose you know anyone who wants a used-once Shimano LX ES51 73*121
splined BB?!? I'll be selling mine on E-bay within the next few days!

Jack

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

Quoted message said:

Daniel Kelly \(AKA Jack\) said:

Hi Sheldon,

Thanks loads for your reply.

I'm not sure if I have a "fat seat tube". My bike is a 2002 Trek 4300 -

the

Quoted message said:

Quoted message said:

specs claim the bike has an 'oversized Alpha aluminium' frame with
'oversized powertubes'. The full specs are here:
http://www.trekbikes.com/bikes/2002/mountain/4300.html#

Also, I'm a little worried about getting a smaller BB because the left

crank

Quoted message said:

Quoted message said:

is only a mm or so away from the BB housing on my 121mm BB. If I swap my
121mm BB for a 118 mm BB, will those 3mm be lost from both sides of the

axel

Quoted message said:

Quoted message said:

(i.e. bringing both the left and right cranks 1.5mm closer to the BB) or
just from the right side of the axel (i.e. the left crank position will

be

Quoted message said:

Quoted message said:

exactly the same on both the 121 and 118mm BBs but the right crank will

be

Quoted message said:

Quoted message said:

3mm closer)?

There may be another fudge factor to look at. I've noted that some
Shimano BB units have about 2mm of unthreaded boss between the threads
and the right flange on the body; when torqued as per spec into a BB
shell that is threaded all the way out, the flange may not seat
against the shell as a result. If there is a gap between the flange
and the BB shell in your installation, you've run aground on this
problem. This has happened to me twice; I've swapped to using generic
BBs for the moment to get around it. The generics are uniformly
threaded all the way to the flange.

--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Surrealism is a pectinated ranzel.

Hi guys,

Just a quick follow-up...

I've swapped out my 121mm BB for a 118mm BB and everything works fine now!
Thanks for your advice, everyone.

Jack.

"Jamie TrailBlazer At Large" <[email hidden]> wrote in message
news:aKGIc.63670$MB3.9129@attbi_s04...

Quoted message said:

I agree with Sheldon the BB is to wide .I have a 68*113 bb for cheep if

you

Quoted message said:

want it.I went to a issis cranks so this is a extra from when I used a XT

on

Quoted message said:

my hard tail.