Shimano rear derailer compatibility

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

Quoted message said:

Hello all --

I know this is a FAQ, but there are so many permutations,
it gets confusing...

I am trying to replace my rear derailer, and I'm worried
about compatibility. I'm switching from a "road" to a
"mountain" derailer because the "road" lines can't handle
the spread of gear-teeth that I need, even though my
bicycle is ostensibly a "road" bike (I never could
understand the distinction).

My current set-up: Shifter: Shimano RSX ("7-speed"😉
Derailer: Shimano RSX ("7-speed"😉 Rear cogs: Shimano
Hyperglide 7-speed

I'm considering getting the Shimano Deore LX rear derailer
or perhaps Deore XT. According to Sheldon Brown's web-site
( sheldonbrown.comdura ace.htmlOpen ↗ and
sheldonbrown.comderailersOpen ↗
rear.html#speeds ), it appears to me that they should be
compatible, but the catalog where I saw them advertised
calls the "Deore" "8/9-speed compatible," and the "Deore
LX" and "Deore XT" ones "9-speed compatible". The fact
that they specifically mention 8-speed on the Deore but
not on the others implies that the LX & XT are *not*
compatible with 8-speed, let alone my 7-speed cogs and
shifters. I'm guessing that they're lying, but can anyone
confirm that for me before I mail-order something that
doesn't work and I have to pay return postage?

I've recently upgraded my old 27" department store 'ten
speed' with a 7-speed 14-34 freewheel and a Deore LX rear
derailer. For no good reason, I occasionally swap between
straight bars with 'old' Deore DX 7-speed shifters, and drop
bars with Sora 7-speed 'brifters'. I have absolutely no
indexing problems with either combination.

(David Favro) said:

I'm considering getting the Shimano Deore LX rear derailer
or perhaps Deore XT. According to Sheldon Brown's web-site
( sheldonbrown.comdura ace.htmlOpen ↗ and
sheldonbrown.comderailersOpen ↗
rear.html#speeds ), it appears to me that they should be
compatible, but the catalog where I saw them advertised
calls the "Deore" "8/9-speed compatible," and the "Deore
LX" and "Deore XT" ones "9-speed compatible". The fact that
they specifically mention 8-speed on the Deore but not on
the others implies that the LX & XT are *not* compatible
with 8-speed, let alone my 7-speed cogs and shifters. I'm
guessing that they're lying,

Lying isn't what they would call it. They are probably
basing these kind of statements on what they still make
in each line and what they can expect others to do with
their parts. Last spring I bought a bike that had a Deore
RD and it was 8 speed. Even though the derailleur had
'mega 9' on it.

There are lags between what is the newest and what is still
available. On lower end bikes like the one I bought, using
older parts (8 speed) reduces costs and helps everyone get
rid of old inventory.

LX and XT are more 'upscale' lines. No sense mentioning 7 or
8 speed because they won't be used on new bikes at this
price point most likely. And Shimano wants the kind of
people who buy XT to throw out all any and all old stuff
that isn't '9-speed.' They have a lot of tooling and setup
costs to recoup!! 🙂

The XT rear derailleur is very nice. Haven't used the LX.
And I have used the 9 speed XT on 7 speeds with no problems,
a 7 speed XT on 9, an 8 speed on 9, and even an 8 speed on 8
and 9 on 9- all worked fine.

(David Favro) said:

My current set-up: Shifter: Shimano RSX ("7-speed"😉
Derailer: Shimano RSX ("7-speed"😉 Rear cogs: Shimano
Hyperglide 7-speed

I'm considering getting the Shimano Deore LX rear derailer
or perhaps Deore XT. According to Sheldon Brown's web-site
( sheldonbrown.comdura ace.htmlOpen ↗ and
sheldonbrown.comderailersOpen ↗
rear.html#speeds ), it appears to me that they should be
compatible, but the catalog where I saw them advertised
calls the "Deore" "8/9-speed compatible," and the "Deore
LX" and "Deore XT" ones "9-speed compatible".

They all use the same indexing-compatible movement ratios,
and can be freely interchanged as long as they're used with
a cassette that's within their capacity. There is widespread
suspicion that the lack of implied 7/8/9 compatibility is a
marketing ploy to get people to buy components that they
don't really need.

Quoted message said:

I don't think it's related, but my rear cogs are currently
11-30 (I want to make that 32 or 34) and my front set-up is
a Shimano 105-triple derailer, 24-46 cogs (I'd like to make
that granny a 22), and Shimano RSX shifter.

I think the 22 might cause the chain to rub the bar on a
105, particularly if you're running on the smaller half of
the rear cassette. You might take a look at how much
clearance you have there now. There are MTB front ders which
can solve this if it's a problem, though I suspect that if
you go to a 34 bailout on the rear, you may find that
there's no need to drop to a 22 on the front.

David Favro said:

.......... I'm guessing that they're lying, but can anyone
confirm that for me before I mail-order something that
doesn't work and I have to pay return postage?

I have used the same XT rear mech with 6 (uniglide) and 9
(hyperglide) cassettes on the same road bike. The shifters
determine the throw of the mech which of course must match
the spacings in the sprockets. I used Shimano 105 six speed
downtube shifters and Dura Ace 9 speed ones. My cassettes
are 14-32 in six and a custom 12-32 in 9. Setup of the 9
speed was more fiddley but this was due to a less than
perfectly aligned hanger.

David Favro said:

I know this is a FAQ, but there are so many permutations,
it gets confusing...

It becomes less confusing if you ignore the marketing hype.

Quoted message said:

I am trying to replace my rear derailer, and I'm worried
about compatibility. I'm switching from a "road" to a
"mountain" derailer because the "road" lines can't handle
the spread of gear-teeth that I need, even though my
bicycle is ostensibly a "road" bike (I never could
understand the distinction).
=20
My current set-up: Shifter: Shimano RSX ("7-speed"😉
Derailer: Shimano RSX ("7-speed"😉 Rear cogs: Shimano
Hyperglide 7-speed

Any Shimano or Shimano-type rear derailer made since 1997
will be=20 compatible with these. No exceptions.

Sheldon "Easier Than You Think" Brown Bristol, U.K. +--------------------------------------------------------
---------+
| I'll be traveling in France and England throughout the
| month | of June. I hope to remain online, but don't
| know what sort | of 'Net access I'll be able to get...
| | I lost 190 MB of mail due to mailbox overload in mid
| June, | so if you wrote me and din=92t get a reply, try
| again. |
+-----------------------------------------------------------
------+ Harris Cyclery, West Newton, Massachusetts Phone 617-244-
9772 FAX 617-244-1041 harriscyclery.comharriscyclery.comOpen ↗ Hard-to-find
parts shipped Worldwide captainbike.comcaptainbike.comOpen ↗
sheldonbrown.comsheldonbrown.comOpen ↗

dfavro-<< My current set-up: Shifter: Shimano RSX ("7-
speed"😉 Derailer: Shimano RSX ("7-speed"😉 Rear cogs: Shimano
Hyperglide 7-speed >><BR><BR> << I'm considering getting the
Shimano Deore LX rear derailer or perhaps Deore XT.
According to Sheldon Brown's web-site >><BR><BR>

Sheldon is correct, Use any shimano MTB rear der w/o
problem or issue.

dfavro-<< but the catalog where I saw them advertised calls
the "Deore" "8/9-speed compatible," and the "Deore LX" and
"Deore XT" ones "9-speed compatible". The fact that they
specifically mention 8-speed on the Deore but not on the
others implies that the LX & XT are *not* >><BR><BR>

They are compatible. Web sites and catalogs are notorious
for being misleading or just being ignorant of what works
and doesn't.

Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St.
Boulder, CO, 80302
(303)440-3535 vecchios.comvecchios.comOpen ↗ "Ruote convenzionali
costruite eccezionalmente bene"

the deore basic deray is a 9/8 speed deray and with the long
cage goes up and on a 34 tooth gear custer cog. the shim
people designed the deray to give warning then survive a
trip up to the 34 while on the 53
CR.i have a '78? raleigh equipped with deore and its a
rideable bike. try a 34 cog and nbar's 14-32 with a 1mm
shim on a deore hub running a very durable hg50 chain.

Thanks to all who responded... I ordered the derailer, I
think it will work.

--
David Favro Please post replies to newsgroup, I am likely to
lose your response in the torrent of spam.