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?
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?
Erik L (antispam: replace "com" with "no" in my e-mail address if you want to communicate with me directly, not recommended if you communicate about a news topic.)
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?
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"
"Erik Lindeberg" <[email hidden]> wrote in message "]news:[email hidden]...
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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.
"Pete Biggs" <[email hidden]> wrote in message news:c5dqcn$fqkc$1@ID-
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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]...
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"Erik Lindeberg" <[email hidden]> wrote in message "]news:[email hidden]...
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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..
