XT rear derailleur

[Constant]

Thanks,

I did visit www.shimano-europe.com allready and did not yet figure out what " Front Difference 22T
max." and "Total Capacity 43T" mean. My guess your info about the wrap capacity is related to that.

Does "Shimano RD-M750-SGS, Rear Derailleur (WIDE RANGE)" mean I'm looking at the long cage version?

Funny thing is: both RD-M750-SG and RD-M750-SGS have a " Front Difference 22T max."

Still a lot to learn.

Constant J. NL

Michael Dart wrote:
> "Constant" <[email protected]> wrote in message
> news:[email protected]...
>
>>Hi
>>
>>I'm thinking about changing my 8speed XT-LX 'gears' to 9-XT. I've heart there are more than one
>>XT-9s rear derailleur: one with a shorter and one with a longer cage.
>>
>>Can anyone tell me when to mount the long version? Is the shorter one the 'normal one?
>>
>>Thanx, Constant J. NL
>>
>
>
> You're talking about chain wrap capacity. To determine long or short cage you take the difference
> (subtract) the size of the big and small rings up front and big and small cogs in back and add the
> two numbers together. This will get you the capacity number. Look this up on the specs for the
> derailleur you are looking at. http://www.shimano-europe.com If the derailleur number is smaller
> then it won't work. Pretty much with triple chainring setups a longer cage is required. The other
> number to consider is max cog size to see if the derailleur will climb up on the largest cog of
> your chosen cassette size.
>
> Mike

 

[Constant]

Hi all,

FYI: The current XT-8s derailleur is mounted on a '98 K2 Proflex 3000 MTB. It's still the first rear
derailleur. It has been shifting fine for 4 years.

-Is there a particulair measurement I can take to find out what is currently mounted: short or
long cage.

The shop I got the bike from tells me the rear derailleur is the older version (with a dark grey
middle part in the parallelogram) and is thus not compatible with 9speed chain etc. The newer XT9s
(all aluminium color) work with 7, 8 or 9. So they say.

To be honest: I have more doubts about the shops advice to also change the front derailleur and thus
(!) move to octalink with a new bottom bracket.

Thanx for all info!! Because the response is very positive, I like to post some more How to
determine what BB I need? -e.g. 73, is that the outer measurement of the BB frame tube? -113 or 118
is the spindle length, but how to determine what to get. I'm thinking of changing back to front, so
starting from 'scratch', not just replacing known parts which I can measure. The current quad
spindle is then replaced by a Octalink.

Constant J. NL

P.S. I know this will cost some. Almost all 'teeth' need replacement, though and I can use all old
8s parts as spares for my day-to-day bike. (Yes, I'm Dutch: 3 bikes in the shed. ;-) )

Michael Dart wrote:
> "Technician" <[email protected]> wrote in message
> news:[email protected]...
>
>>In article <[email protected]>, [email protected] says...
>>
>>>"Technician" <[email protected]> wrote in message
>>>news:[email protected]...
>>>| In article <[email protected]>, [email protected] says...
>>>| > On Mon, 12 May 2003 23:03:29 +0200, Constant
>>>| > <[email protected]> wrote:
>>>| >
>>>| > >Hi
>>>| > >
>>>| > >I'm thinking about changing my 8speed XT-LX 'gears' to 9-XT. I've heart there are more than
>>>| > >one XT-9s rear derailleur: one with
>>
> a
>
>>>| > >shorter and one with a longer cage.
>>>| > >
>>>| > >Can anyone tell me when to mount the long version? Is the shorter
>>
> one
>
>>>| > >the 'normal one?
>>>| > >
>>>| > >Thanx, Constant J. NL
>>>| >
>>>| > No need to change the rear derailer. your 8 speed one will work
>>
> fine.
>
>>>| >
>>>| > Bob
>>>| >
>>>|
>>>| unless he has 9-speed cogs...
>>>|
>>>| the point was he was wondering if the longer or shorter cage is
>>
> better,
>
>>>| not weather or not he should upgrade to 9-speed.
>>>
>>>That is true, according to Shimano, however, I have a **7** speed XT derailleur shifting a 9
>>>speed system perfectly.
>>>
>>
>>Interesting, so is the opposite true? will a 7-speed derailer shift a 9 speed system?
>>
>>I only ask because should i wish to upgrade to 9-speed, it would be a lot cheaper to only have to
>>swap out the front shifter and rear wheel (and cogset of course).
>>--
>>~Travis
>>
>
>
> Indexing is done at the shifter not the derailleur. So as long as the specs on the derailleur like
> max cog size and chain wrap capacity match it will work fine 7,8 or 9 speed.
>
> Mike

 

[Michael Dart]

"Constant" <[email protected]> wrote in message
news:[email protected]...
> Thanks,
>
> I did visit www.shimano-europe.com allready and did not yet figure out what " Front Difference
> 22T max." and "Total Capacity 43T" mean. My guess your info about the wrap capacity is related
> to that.

Yeah that's it. There is a 22t max difference between the smallest and largest ring in the front and
as I said the difference in the front plus the difference in the small and large cog in the rear is
the Total Capacity number. For example

Front large 42t - small 22t =20t Rear large 34t - small 11t = 23t 20t+23t = 43t

so SGS, or long cage is the one you want for this combo.

>
> Does "Shimano RD-M750-SGS, Rear Derailleur (WIDE RANGE)" mean I'm looking at the long cage
> version?

SGS is long cage, GS is mid or short cage.

>
> Funny thing is: both RD-M750-SG and RD-M750-SGS have a " Front Difference 22T max."
>
> Still a lot to learn.
>
> Constant J. NL
>
>
>
>
> Michael Dart wrote:
> > "Constant" <[email protected]> wrote in message
> > news:[email protected]...
> >
> >>Hi
> >>
> >>I'm thinking about changing my 8speed XT-LX 'gears' to 9-XT. I've heart there are more than one
> >>XT-9s rear derailleur: one with a shorter and one with a longer cage.
> >>
> >>Can anyone tell me when to mount the long version? Is the shorter one the 'normal one?
> >>
> >>Thanx, Constant J. NL
> >>
> >
> >
> > You're talking about chain wrap capacity. To determine long or short
cage
> > you take the difference (subtract) the size of the big and small rings
up
> > front and big and small cogs in back and add the two numbers together.
This
> > will get you the capacity number. Look this up on the specs for the derailleur you are looking
> > at. http://www.shimano-europe.com If the derailleur number is smaller then it won't work. Pretty
> > much with
triple
> > chainring setups a longer cage is required. The other number to
consider is
> > max cog size to see if the derailleur will climb up on the largest cog
of
> > your chosen cassette size.
> >
> > Mike
> >

 

[Constant]

Thanx again.

Not going to the shop, but buy from the internet can save me 25%! (at least).

CJ

Michael Dart wrote:
> "Constant" <[email protected]> wrote in message
> news:[email protected]...
>
>>Thanks,
>>
>>I did visit www.shimano-europe.com allready and did not yet figure out what " Front Difference
>>22T max." and "Total Capacity 43T" mean. My guess your info about the wrap capacity is related
>>to that.
>
>
> Yeah that's it. There is a 22t max difference between the smallest and largest ring in the front
> and as I said the difference in the front plus the difference in the small and large cog in the
> rear is the Total Capacity number. For example
>
> Front large 42t - small 22t =20t Rear large 34t - small 11t = 23t 20t+23t = 43t
>
> so SGS, or long cage is the one you want for this combo.
>
>
>>Does "Shimano RD-M750-SGS, Rear Derailleur (WIDE RANGE)" mean I'm looking at the long cage
>>version?
>
>
> SGS is long cage, GS is mid or short cage.
>
>
>>Funny thing is: both RD-M750-SG and RD-M750-SGS have a " Front Difference 22T max."
>>
>>Still a lot to learn.
>>
>>Constant J. NL
>>
>>
>>
>>
>>Michael Dart wrote:
>>
>>>"Constant" <[email protected]> wrote in message
>>>news:[email protected]...
>>>
>>>
>>>>Hi
>>>>
>>>>I'm thinking about changing my 8speed XT-LX 'gears' to 9-XT. I've heart there are more than one
>>>>XT-9s rear derailleur: one with a shorter and one with a longer cage.
>>>>
>>>>Can anyone tell me when to mount the long version? Is the shorter one the 'normal one?
>>>>
>>>>Thanx, Constant J. NL
>>>>
>>>
>>>
>>>You're talking about chain wrap capacity. To determine long or short
>>
> cage
>
>>>you take the difference (subtract) the size of the big and small rings
>>
> up
>
>>>front and big and small cogs in back and add the two numbers together.
>>
> This
>
>>>will get you the capacity number. Look this up on the specs for the derailleur you are looking
>>>at. http://www.shimano-europe.com If the derailleur number is smaller then it won't work. Pretty
>>>much with
>>
> triple
>
>>>chainring setups a longer cage is required. The other number to
>>
> consider is
>
>>>max cog size to see if the derailleur will climb up on the largest cog
>>
> of
>
>>>your chosen cassette size.
>>>
>>>Mike
>>>
>>>
>>

 

[Nelson Binch]

"Constant" <[email protected]> wrote in message
news:[email protected]...
| Hi all,
|
| FYI: The current XT-8s derailleur is mounted on a '98 K2 Proflex 3000 MTB. It's still the first
| rear derailleur. It has been shifting fine for 4 years.
|
| -Is there a particulair measurement I can take to find out what is currently mounted: short or
| long cage.

Usually the letters GS or SGS are stamped somewhere on the back of the cage plates.

| The shop I got the bike from tells me the rear derailleur is the older version (with a dark grey
| middle part in the parallelogram) and is thus not compatible with 9speed chain etc.

Bull. Unless you're going to switch to a 34 max cog, it'll work fine.

| The newer XT9s (all aluminium color) work with 7, 8 or 9. So they say.

The quality is better, but like I said before, you don't really need it.

| To be honest: I have more doubts about the shops advice to also change the front derailleur

Why? Usually it's not needed. If you have problems, then do, but otherwise don't worry about it.

| and thus (!) move to octalink with a new bottom bracket.

Again why? All my bikes still have the old square taper. Never had a problem.

| Thanx for all info!! Because the response is very positive, I like to post some more How to
| determine what BB I need? -e.g. 73, is that the outer measurement of the BB frame tube? -113 or
| 118 is the spindle length, but how to determine what to get. I'm thinking of changing back to
| front, so starting from 'scratch', not just replacing known parts which I can measure. The current
| quad spindle is then replaced by a Octalink.

Okay, when the specs for a crank call for one of two spindle lengths, then you measure the seat tube
where the front derailleur clamps. If it is 1 1/8 inch (28.6mm) then use the shorter selection. If
it is 1 1/4 inch (31.9mm) then you can use either, though usually the shorter is best. If you have a
1 3/8 inch (34.7mm) tube, then you use the longest one. This is a rule of thumb and sometimes
chain-line issues can upset the rule.

---
__o _`\(,_ Cycling is life, (_)/ (_) all the rest, just details. Nelson Binch =^o.o^=
http://intergalax.com

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