XTR sprockets

Erik Lindeberg said:

1. At the Shimano web site the rear derailleurs (RD-M960)
are specified to service a 11T minimum and 34T maximum
sprocket and 22T maximum front difference. All this
information is clear to me, but I do not understand
the specification called "Total Capacity" (43T for SGS
and 33T for SG). I understand that SGS (the derailleur
with super long arm) can take up more slack than the
SG (long arm) and also can handle a larger rear
sprockets, but what does the notation 33T and 43T
actually refer to?

total capacity = (largest chainring - smallest chainring) +
(largest sprocket - smallest sprocket)

See sheldonbrown.comgloss ca m.htmlOpen ↗ - Capacity

note: "Competent riders can considerably exceed the
official rated capacity, since they will not misuse
the granny ring by running it with the smaller rear
sprockets, so it doesn't matter if the chain hangs
slack in those gears"

~PB

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

Quoted message said:

2. In all groups from Deore to Deore XT there is always a
crank and a front derailleur that can be used with a
maximum 48T front sprocket. On the XTR, however, (M960
series) there seems to be no option to fit a larger
than 44T sprocket on the crank and the front derailleur
FD-M961 can only service a 46T sprocket. Is this right
or am I missing something? Is there a FC-M961 crank
around the corner? I will build a no-compromise
cross/hybrid with 700C wheels and 11-34 rear sprocket
and 26-36-48 crank and am considering the XTR group
M960. Do I really have to stick with XT if I shall get
my favorite gear ratios?

Pete already answered the first question so I'll just
address your second. The main issue for max chainring size
AIUI is the radius of the cage of the F Der. You might get
away with 48T on one rated for 46T, and Sheldon on his site
describes somewhere reprofiling a cage with a dremel tool.
Otherwise if XT is rated for 48T you'll either have to use
that for the FD (obviously you can still put XTR on the
rear), or consider a road FD. FWIW, I have exactly that on
my commuter bike - long cage XTR M960 on the rear and 105
on the front with 52-42-30 chainrings. ATM the rear
cassette is a 12-23, but I intend replacing it with an 11-
32 when I go touring, which was the reason for choosing the
XTR - 21 rear tooth difference + 22 front adds up nicely to
its 43T max capacity.

Remember that the M960 is rapid-rise BTW - quickest shifting
is lower, not higher.

Rich

"Pete Biggs" <[email hidden]> wrote in message
news:c5dqcn$fqkc$1@ID-

Quoted message said:

Quoted message said:

but what does the notation 33T and 43T actually
refer to?

total capacity = (largest chainring - smallest chainring)
+ (largest sprocket - smallest sprocket) See sheldonbrown.comgloss caOpen ↗
m.html - Capacity
note: "Competent riders can considerably exceed the
official rated capacity, since they will not misuse
the granny ring by running it with the smaller rear
sprockets, so it doesn't matter if the chain hangs
slack in those gears"

Thank you, so I will need a capacity: (48 - 26) + (34 -11) =
45. Despite I consider myself to be a fairly competent rider
I will need the extra-long arm (SGS). Erik

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

Quoted message said:

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

Quoted message said:

2. In all groups from Deore to Deore XT there is always
a crank and a front derailleur that can be used with
a maximum 48T front

sprocket.

Quoted message said:

Quoted message said:

On the XTR, however, (M960 series) there seems to be no
option to fit a larger than 44T sprocket on the crank
and the front derailleur FD-M961 can only service a 46T
sprocket. Is this right or am I missing something? Is
there a FC-M961 crank around the corner? I will build a
no-compromise cross/hybrid with 700C wheels and 11-34
rear sprocket and 26-36-48 crank and am considering the
XTR group M960. Do I really have to stick with XT if I
shall get my favorite gear

ratios?

Quoted message said:

Pete already answered the first question so I'll just
address your second. The main issue for max chainring size
AIUI is the radius of the cage of

the

Quoted message said:

F Der. You might get away with 48T on one rated for 46T,
and Sheldon on

his

Quoted message said:

site describes somewhere reprofiling a cage with a dremel
tool. Otherwise if XT is rated for 48T you'll either have
to use that for the FD

(obviously

Quoted message said:

you can still put XTR on the rear), or consider a road FD.
FWIW, I have exactly that on my commuter bike - long cage
XTR M960 on the rear and 105

on

Quoted message said:

the front with 52-42-30 chainrings. ATM the rear cassette
is a 12-23,

but

Quoted message said:

I intend replacing it with an 11-32 when I go touring,
which was the

reason

Quoted message said:

for choosing the XTR - 21 rear tooth difference + 22 front
adds up nicely

to

Quoted message said:

its 43T max capacity.

Remember that the M960 is rapid-rise BTW - quickest
shifting is lower, not higher.

Rich

Thank you, but is it possible to put larger than 44T
chainrings on the XTR crank? Are these rings different than
those for XT? I will take the rapid-rise challenge. Actually
I have rapid-rise on my summer house old cross bike (Nexave
400T). It is a pain to get used to, but with the combined
controller on M960 I hope it will be easier. It seems to
have come to stay..

Erik