Replacing a rear derailleur

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

Quoted message said:

Through some astounding stupidity on my part, I have managed to
destroy my rear derailleur. The bike is a Dawes Mojave with Shimano
"tourney" TX50 rear derailleur. I can obtain a replacement part from a
seller on ebay.

Because I'm not experienced in bike maintenance I am supposing that I
have to go to a shop and have the whole lot done at presumably a high
price. I had a look at the setup and read some web pages about rear
derailleur replacement. The work at the rear end doesn't appear that
complex. But I have indexed front gear shifts, and for the life of me
I can't see how I would replace the cable. Looking at the cable, it
appears to have a lug on the rear derailleur end which suggests to me
that the whole cable must be threaded through the derailleur, and
secured at the handlebar gearshift end. Is this likely to be true? If
not or even so, if I attached a new derailleur, how do I connect up
the cable?

Is your busted RD attached to your bike by its own claw-like hanger, like
this
http://www.jensonusa.com/store/product/RD406A03-Shimano+Tourney+Rd-Tx50+Rear+Derailleur.aspx?
Or by a Allen key bolt - which means your bike frame has a derailleur
hanger?
http://www.nashbar.com/profile_moreimages.cfm?category=83&subcategory=1039&sku=15301&brand=
Either way, buy a new RD and it comes with an instruction sheet a monkey can
follow.

Bellsouth Ijit 2.0 - Hayfever Edition ® said:

Is your busted RD attached to your bike by its own claw-like hanger, like
thishttp://www.jensonusa.com/store/product/RD406A03-Shimano+Tourney+Rd-Tx....
Or by a Allen key bolt - which means your bike frame has a derailleur
hanger?http://www.nashbar.com/profile_moreimages.cfm?category=83&subcategory...
Either way, buy a new RD and it comes with an instruction sheet a monkey can
follow.

It's the Allen key direct attachment. As in:

http://cgi.ebay.co.uk/SHIMANO-TOURNEY-6-7-SPEED-REAR-MECH-DERAILLEUR-TX50D_W0QQitemZ230145100010QQihZ013QQcategoryZ42329QQtcZphotoQQcmdZViewItem

The way I feel at the moment saying that a monkey could follow the
instructions does not make me confident that I could.

But, I took the cover off the front combined gear lever/brake lever
assembly, and can see that the gear cable as a big lug on the end, and
how it attaches. The other end also has a smaller lug thing on it.
Looking at how the cable goes through the derailleur, it would only be
possible to thread it through if one end of the cable was naked. So
that means that one lug was probably attached during the manufacture/
assembly of the bike. I suppose I could chop one lug off, and try to
thread the new derailleur, and solder it afterwards, but if that makes
the cable too short, then I'd need a new cable.

If I now have to change derailleur, could I put a "better" derailleur
on? Or would it be better to stick with the original part?

Quoted message said:

Bellsouth Ijit 2.0 - Hayfever Edition ® said:

Is your busted RD attached to your bike by its own claw-like hanger, like
thishttp://www.jensonusa.com/store/product/RD406A03-Shimano+Tourney+Rd-Tx....
Or by a Allen key bolt - which means your bike frame has a derailleur
hanger?http://www.nashbar.com/profile_moreimages.cfm?category=83&subcategory...
Either way, buy a new RD and it comes with an instruction sheet a monkey can
follow.

It's the Allen key direct attachment. As in:

http://cgi.ebay.co.uk/SHIMANO-TOURNEY-6-7-SPEED-REAR-MECH-DERAILLEUR-TX50D_W0QQitemZ230145100010QQihZ013QQcategoryZ42329QQtcZphotoQQcmdZViewItem

The way I feel at the moment saying that a monkey could follow the
instructions does not make me confident that I could.

But, I took the cover off the front combined gear lever/brake lever
assembly, and can see that the gear cable as a big lug on the end, and
how it attaches. The other end also has a smaller lug thing on it.
Looking at how the cable goes through the derailleur, it would only be
possible to thread it through if one end of the cable was naked. So
that means that one lug was probably attached during the manufacture/
assembly of the bike. I suppose I could chop one lug off, and try to
thread the new derailleur, and solder it afterwards, but if that makes
the cable too short, then I'd need a new cable.

The "lug" at the derailer end is probably a crimp-on bit of soft metal
(aluminum?). It will be fairly easy to remove with a pliers. Just grab
the "lug" and pull. After you remove it, the cable end may be frayed.
This will make it more difficult to thread the cable through the new
derailer. A new cable might be handy. Either way, you'll want a new
crimp-on for the end of the cable.

If you want to remove the entire cable, you will need to remove it from
the shifter end. That "lug" is permanent.

Quoted message said:

If I now have to change derailleur, could I put a "better" derailleur
on? Or would it be better to stick with the original part?

I doubt you'll notice any performance difference with a better derailer.
Stick with Shimano since you have indexed gears, and if you have a long
cage derailer, get a long cage replacement. I'm not familiar enough with
Shimano Tourney components to know if they're long or short cage. The
derailer shown in the ebay link is almost definitely a long cage derailer.

--
Dave
dvt at psu dot edu

Everyone confesses that exertion which brings out all the powers of body
and mind is the best thing for us; but most people do all they can to
get rid of it, and as a general rule nobody does much more than
circumstances drive them to do. -Harriet Beecher Stowe, abolitionist and
novelist (1811-1896)

Quoted message said:

Bellsouth Ijit 2.0 - Hayfever Edition ® said:

Is your busted RD attached to your bike by its own claw-like hanger, like
thishttp://www.jensonusa.com/store/product/RD406A03-Shimano+Tourney+Rd-Tx...
Or by a Allen key bolt - which means your bike frame has a derailleur
hanger?http://www.nashbar.com/profile_moreimages.cfm?category=83&subcategory...
Either way, buy a new RD and it comes with an instruction sheet a monkey can
follow.

It's the Allen key direct attachment. As in:

http://cgi.ebay.co.uk/SHIMANO-TOURNEY-6-7-SPEED-REAR-MECH-DERAILLEUR-TX50D_W0QQitemZ230145100010QQihZ013QQcategoryZ42329QQtcZphotoQQcmdZViewItem

The way I feel at the moment saying that a monkey could follow the
instructions does not make me confident that I could.

But, I took the cover off the front combined gear lever/brake lever
assembly, and can see that the gear cable as a big lug on the end, and
how it attaches. The other end also has a smaller lug thing on it.
Looking at how the cable goes through the derailleur, it would only be
possible to thread it through if one end of the cable was naked. So
that means that one lug was probably attached during the manufacture/
assembly of the bike. I suppose I could chop one lug off, and try to
thread the new derailleur, and solder it afterwards, but if that makes
the cable too short, then I'd need a new cable.

If I now have to change derailleur, could I put a "better" derailleur
on? Or would it be better to stick with the original part?

The rear derailleur end of the cable likely has a ferrule on it. This is
basically the same as the plastic wrapping on the end of a shoe lace.
It's there to keep the cable from fraying. It's crimped in place and
should be easy to remove. If the ferrule has done its job then the cable
end will be nicely compact and easy to thread back through a replacement
derailleur.

Quoted message said:

Through some astounding stupidity on my part, I have managed to
destroy my rear derailleur. The bike is a Dawes Mojave with Shimano
"tourney" TX50 rear derailleur. I can obtain a replacement part from a
seller on ebay.

Because I'm not experienced in bike maintenance I am supposing that I
have to go to a shop and have the whole lot done at presumably a high
price. I had a look at the setup and read some web pages about rear
derailleur replacement. The work at the rear end doesn't appear that
complex. But I have indexed front gear shifts, and for the life of me
I can't see how I would replace the cable. Looking at the cable, it
appears to have a lug on the rear derailleur end which suggests to me
that the whole cable must be threaded through the derailleur, and
secured at the handlebar gearshift end. Is this likely to be true? If
not or even so, if I attached a new derailleur, how do I connect up
the cable?

None of this is really difficult, but it takes time to describe over
usenet. Get a book on bike maintenance. Any one would have this stuff
in it.

As far as the cable goes, there is a bulbous end that fits in a little
recess in the shifter. You disconnect the cable at the derailleur end,
and push it up into the shifter by grabbing the bare cable as near to
the shifter as you can, and push. It should pop out a bit inside the
shifter. Then you thread the new one from the shifter back through the
cables, to the derailleur. It's easier than it sounds.

--

David L. Johnson

Become MicroSoft-free forever. Ask me how.

Quoted message said:

But, I took the cover off the front combined gear lever/brake lever
assembly, and can see that the gear cable as a big lug on the end, and
how it attaches. The other end also has a smaller lug thing on it.
Looking at how the cable goes through the derailleur, it would only be
possible to thread it through if one end of the cable was naked.

Right. The end near the derailleur is only crimped on. It's there to
keep the cable from fraying. The business end is at the shifter, and
that lug comes with the new cable.
So

Quoted message said:

that means that one lug was probably attached during the manufacture/
assembly of the bike. I suppose I could chop one lug off, and try to
thread the new derailleur, and solder it afterwards, but if that makes
the cable too short, then I'd need a new cable.

Get a new cable. They are cheap, and they do wear.

Quoted message said:

If I now have to change derailleur, could I put a "better" derailleur
on? Or would it be better to stick with the original part?

Any Shimano derailleur will work fine.

--

David L. Johnson

Become MicroSoft-free forever. Ask me how.

Quoted message said:

Through some astounding stupidity on my part, I have managed to
destroy my rear derailleur. The bike is a Dawes Mojave with Shimano
"tourney" TX50 rear derailleur. I can obtain a replacement part from a
seller on ebay.

Because I'm not experienced in bike maintenance I am supposing that I
have to go to a shop and have the whole lot done at presumably a high
price. I had a look at the setup and read some web pages about rear
derailleur replacement. The work at the rear end doesn't appear that
complex. But I have indexed front gear shifts, and for the life of me
I can't see how I would replace the cable. Looking at the cable, it
appears to have a lug on the rear derailleur end which suggests to me
that the whole cable must be threaded through the derailleur, and
secured at the handlebar gearshift end. Is this likely to be true? If
not or even so, if I attached a new derailleur, how do I connect up
the cable?

If you buy a new (~$15) Tourney derailleur in a box it includes
directions with drawings. Usually the cable is not replaced with a rear
changer replacement unless the wire is frayed or otherwise damaged.

The small crimp at the very end of the wire hanging off your derailleur
is easily removed by snipping the wire. Pull the wire out of the
derailleur, change them, install and secure the wire in the new
derailleur. Crimp a new end on the wire.

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

Quoted message said:

Bellsouth Ijit 2.0 - Hayfever Edition ® said:

Is your busted RD attached to your bike by its own claw-like hanger, like
thishttp://www.jensonusa.com/store/product/RD406A03-Shimano+Tourney+Rd-Tx...
Or by a Allen key bolt - which means your bike frame has a derailleur
hanger?http://www.nashbar.com/profile_moreimages.cfm?category=83&subcategory...
Either way, buy a new RD and it comes with an instruction sheet a monkey can
follow.

It's the Allen key direct attachment. As in:

http://cgi.ebay.co.uk/SHIMANO-TOURNEY-6-7-SPEED-REAR-MECH-DERAILLEUR-TX50D_W0QQitemZ230145100010QQihZ013QQcategoryZ42329QQtcZphotoQQcmdZViewItem

The way I feel at the moment saying that a monkey could follow the
instructions does not make me confident that I could.

But, I took the cover off the front combined gear lever/brake lever
assembly, and can see that the gear cable as a big lug on the end, and
how it attaches. The other end also has a smaller lug thing on it.
Looking at how the cable goes through the derailleur, it would only be
possible to thread it through if one end of the cable was naked. So
that means that one lug was probably attached during the manufacture/
assembly of the bike. I suppose I could chop one lug off, and try to
thread the new derailleur, and solder it afterwards, but if that makes
the cable too short, then I'd need a new cable.

If I now have to change derailleur, could I put a "better" derailleur
on? Or would it be better to stick with the original part?

The low to midrange Shimanos are all of a type - choose your level of
price, durability and aesthetic qualities: mostly nylon, nylon with
pressed steel plates, some aluminum with nylon, mostly aluminum, pretty
finish, black finish, etc. They'll all shift fine when new and will
shift sloppily when the pivots are worn. $15 to $99 in many increments.

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

Thanks to all for the advice. Yesterday I bought the replacement
parts, and I'll see how I get on replacing them tomorrow evening, the
first time I can allocate a good stretch of time to the job.

email hidden said:

Through some astounding stupidity on my part, I have managed to
destroy my rear derailleur. The bike is a Dawes Mojave with Shimano
"tourney" TX50 rear derailleur. I can obtain a replacement part from a
seller on ebay.

Because I'm not experienced in bike maintenance I am supposing that I
have to go to a shop and have the whole lot done at presumably a high
price.

Geee, how about a $25 RD and $10 labor..is this 'incredibly high'?.
For a new RD installed and adjusted well?

I had a look at the setup and read some web pages about rear

Quoted message said:

derailleur replacement. The work at the rear end doesn't appear that
complex. But I have indexed front gear shifts, and for the life of me
I can't see how I would replace the cable. Looking at the cable, it
appears to have a lug on the rear derailleur end which suggests to me
that the whole cable must be threaded through the derailleur, and
secured at the handlebar gearshift end. Is this likely to be true? If
not or even so, if I attached a new derailleur, how do I connect up
the cable?