Shimano DA7800 RD question

I use a Shimnao Compact Crank 50/34 w/ 9 speed setup, 11-28 in rear. I'm
currently using a DA7700SS RD. I know the max. capacity of this derailleur
is 27 and there is minor contact even with the B screw set in all the way and
I even exchanged the B screw for another one with 1mm longer reach. Will
going to the GS version of this Derailleur solve the problem, though I only
hear the contact when I have the bike on my workstand, riding it never
seems to be a problem. I believe the GS version also states 27T max. in
rear but has a larger overall capacity.

And yes at my age and weight and local steep hills the 34-28 is nice and
needed. Thanks.

On 22 Mar, 21:22, RS wrote:
I use a Shimnao Compact Crank 50/34 w/ 9 speed setup, 11-28 in rear. *I'm
currently using a DA7700SS RD. *I know the max. capacity of this derailleur
is 27 and there is minor contact even with the B screw set in all the way and
I even exchanged the B screw for another one with 1mm longer reach. *Will
going to the GS version of this Derailleur solve the problem, though I only
hear the contact when I have the bike on my workstand, riding it never
seems to be a problem. *I believe the GS version also states 27T max. in
rear but has a larger overall capacity.

And yes at my age and weight and local steep hills the 34-28 is nice and
needed. *Thanks.

Road derailler used to be classed as 26 when they did 28-32
dependingon wwhere in the dropout the axle was. With a 16 teeth
difference up front your losing that extra clearance from the
sprockets that you would normally have. A smaller difference up front
should improve the action of the rear mech.

TJ

On Mar 22, 3:22*pm, RS wrote:
I use a Shimnao Compact Crank 50/34 w/ 9 speed setup, 11-28 in rear. *I'm
currently using a DA7700SS RD. *I know the max. capacity of this derailleur
is 27 and there is minor contact even with the B screw set in all the way and
I even exchanged the B screw for another one with 1mm longer reach. *Will
going to the GS version of this Derailleur solve the problem, though I only
hear the contact when I have the bike on my workstand, riding it never
seems to be a problem. *I believe the GS version also states 27T max. in
rear but has a larger overall capacity.

And yes at my age and weight and local steep hills the 34-28 is nice and
needed. *Thanks.

Are you sure the chain isn't too long? Try to gently go into big-big
combo and see if the chain going thru te rear derailleur makes a
'steep' or shallow 'S'. If steep, may be able to take one link out.
shimano rear derailleurs or the road max it at '27' cuz that's the
biggest road cassette they sell. Actual 'limit' depends on other
things including the crank ring ranges.

In article 8c2ac0c1-3c77-4ff1-ae14-
,
says...


On Mar 22, 3:22*pm, RS wrote:
I use a Shimnao Compact Crank 50/34 w/ 9 speed setup, 11-28 in rear.
*I'm
currently using a DA7700SS RD. *I know the max. capacity of this
derailleur
is 27 and there is minor contact even with the B screw set in all the
way and
I even exchanged the B screw for another one with 1mm longer reach.
*Will
going to the GS version of this Derailleur solve the problem, though I
only
hear the contact when I have the bike on my workstand, riding it never
seems to be a problem. *I believe the GS version also states 27T max.
in
rear but has a larger overall capacity.

And yes at my age and weight and local steep hills the 34-28 is nice
and
needed. *Thanks.

Are you sure the chain isn't too long? Try to gently go into big-big
combo and see if the chain going thru te rear derailleur makes a
'steep' or shallow 'S'. If steep, may be able to take one link out.
shimano rear derailleurs or the road max it at '27' cuz that's the
biggest road cassette they sell. Actual 'limit' depends on other
things including the crank ring ranges.

I'll check chain length though believe I have it set properly for the wide
range I"m using. I use big-big often. Thanks.

On Mar 23, 11:16*am, RS wrote:
In article 8c2ac0c1-3c77-4ff1-ae14-
,
says...





On Mar 22, 3:22*pm, RS wrote:
I use a Shimnao Compact Crank 50/34 w/ 9 speed setup, 11-28 in rear.
*I'm
currently using a DA7700SS RD. *I know the max. capacity of this
derailleur
is 27 and there is minor contact even with the B screw set in all the
way and
I even exchanged the B screw for another one with 1mm longer reach.
*Will
going to the GS version of this Derailleur solve the problem, though I
only
hear the contact when I have the bike on my workstand, riding it never
seems to be a problem. *I believe the GS version also states 27T max..
in
rear but has a larger overall capacity.

And yes at my age and weight and local steep hills the 34-28 is nice
and
needed. *Thanks.

Are you sure the chain isn't too long? Try to gently go into big-big
combo and see if the chain going thru te rear derailleur makes a
'steep' or shallow 'S'. If steep, may be able to take one link out.
shimano rear derailleurs or the road max it at '27' cuz that's the
biggest road cassette they sell. Actual 'limit' depends on other
things including the crank ring ranges.

I'll check chain length though believe I have it set properly for the wide
range I"m using. *I use big-big often. *Thanks.

If you can remove one link and still get big-big w/o hurting anything,
that will rotate the upper pulley away from the biggest cog,
eliminating the rub.

In article 72481d88-a31b-4cbe-a4ec-
,
says...


On Mar 22, 4:22*pm, RS wrote:
I use a Shimnao Compact Crank 50/34 w/ 9 speed setup, 11-28 in rear.
*I'm
currently using a DA7700SS RD. *I know the max. capacity of this
derailleur
is 27 and there is minor contact even with the B screw set in all the
way and
I even exchanged the B screw for another one with 1mm longer reach.
*Will
going to the GS version of this Derailleur solve the problem, though I
only
hear the contact when I have the bike on my workstand, riding it never
seems to be a problem. *I believe the GS version also states 27T max.
in
rear but has a larger overall capacity.

And yes at my age and weight and local steep hills the 34-28 is nice
and
needed. *Thanks.

I put a B screw with about 4 mm greater length in a 7700GS RD and it
was used with a 50/34 and 11-32 10s rear cassette (IRD, not ShimaNO).
Works like a champ, shifts perfectly. I would suspect that you could
do the same with the 7700SS.

As a side note, I used the same setup (50/34 with 11-32 cassette) with
campy gear and the rear der (Centaur long cage) worked fine without
touching the B screw or having to severely reduce the chain length to
get the top jockey wheel to clear the cassette.

Reason #764 why campy road gear is the clear choice for road use.

D'ohBoy

With a longer B screw screwed out the angle of the 7700 SS becomes too
horizontal and won't hit the stop on my frame. But I'll revisit that solution,
possible I can get another millimeter or two out of it which may just do it.

On Mar 25, 12:22*pm, RS wrote:
In article 72481d88-a31b-4cbe-a4ec-
,
says...





On Mar 22, 4:22*pm, RS wrote:
I use a Shimnao Compact Crank 50/34 w/ 9 speed setup, 11-28 in rear.
*I'm
currently using a DA7700SS RD. *I know the max. capacity of this
derailleur
is 27 and there is minor contact even with the B screw set in all the
way and
I even exchanged the B screw for another one with 1mm longer reach.
*Will
going to the GS version of this Derailleur solve the problem, though I
only
hear the contact when I have the bike on my workstand, riding it never
seems to be a problem. *I believe the GS version also states 27T max..
in
rear but has a larger overall capacity.

And yes at my age and weight and local steep hills the 34-28 is nice
and
needed. *Thanks.

I put a B screw with about 4 mm greater length in a 7700GS RD and it
was used with a 50/34 and 11-32 10s rear cassette (IRD, not ShimaNO).
Works like a champ, shifts perfectly. *I would suspect that you could
do the same with the 7700SS.

As a side note, I used the same setup (50/34 with 11-32 cassette) with
campy gear and the rear der (Centaur long cage) worked fine without
touching the B screw or having to severely reduce the chain length to
get the top jockey wheel to clear the cassette.

Reason #764 why campy road gear is the clear choice for road use.

D'ohBoy

With a longer B screw screwed out the angle of the 7700 SS becomes too
horizontal and won't hit the stop on my frame. *But I'll revisit that solution,
possible I can get another millimeter or two out of it which may just do it.

Sorry - that was a 7800GS Rder i did that with. But the geometry and
cage are the same.

D'ohBoy

In article 25c76e6e-b9dd-46dd-8839-
,
says...


On Mar 25, 12:22*pm, RS wrote:
In article 72481d88-a31b-4cbe-a4ec-
,
says...





On Mar 22, 4:22*pm, RS wrote:
I use a Shimnao Compact Crank 50/34 w/ 9 speed setup, 11-28 in
rear.
*I'm
currently using a DA7700SS RD. *I know the max. capacity of this
derailleur
is 27 and there is minor contact even with the B screw set in all the
way and
I even exchanged the B screw for another one with 1mm longer
reach.
*Will
going to the GS version of this Derailleur solve the problem, though
I
only
hear the contact when I have the bike on my workstand, riding it
never
seems to be a problem. *I believe the GS version also states 27T
max.
in
rear but has a larger overall capacity.

And yes at my age and weight and local steep hills the 34-28 is nice
and
needed. *Thanks.

I put a B screw with about 4 mm greater length in a 7700GS RD and
it
was used with a 50/34 and 11-32 10s rear cassette (IRD, not
ShimaNO).
Works like a champ, shifts perfectly. *I would suspect that you could
do the same with the 7700SS.

As a side note, I used the same setup (50/34 with 11-32 cassette)
with
campy gear and the rear der (Centaur long cage) worked fine without
touching the B screw or having to severely reduce the chain length to
get the top jockey wheel to clear the cassette.

Reason #764 why campy road gear is the clear choice for road use.

D'ohBoy

With a longer B screw screwed out the angle of the 7700 SS becomes
too
horizontal and won't hit the stop on my frame. *But I'll revisit that
solution,
possible I can get another millimeter or two out of it which may just do
it.

Sorry - that was a 7800GS Rder i did that with. But the geometry and
cage are the same.

D'ohBoy

OK, thanks. The Longer cage of the GS probably makes a difference. I
have another bike with an Ultegra RD6500GS and it works fine in an 8-
speed setup with a 50/34 crank and 11-28 in back. Guess I'm stuck on the
50-11 high to the 34-28 low, seems to suit all situations. 50-12 just isn't
high enough but I will admit to occasionally wishing I had a bail-out 34-30

On 26 Mar, 00:39, RS wrote:
In article 25c76e6e-b9dd-46dd-8839-
,
says...





On Mar 25, 12:22*pm, RS wrote:
In article 72481d88-a31b-4cbe-a4ec-
,
says...

On Mar 22, 4:22*pm, RS wrote:
I use a Shimnao Compact Crank 50/34 w/ 9 speed setup, 11-28 in
rear.
*I'm
currently using a DA7700SS RD. *I know the max. capacity of this
derailleur
is 27 and there is minor contact even with the B screw set in all the
way and
I even exchanged the B screw for another one with 1mm longer
reach.
*Will
going to the GS version of this Derailleur solve the problem, though
I
only
hear the contact when I have the bike on my workstand, riding it
never
seems to be a problem. *I believe the GS version also states 27T
max.
in
rear but has a larger overall capacity.

And yes at my age and weight and local steep hills the 34-28 is nice
and
needed. *Thanks.

I put a B screw with about 4 mm greater length in a 7700GS RD and
it
was used with a 50/34 and 11-32 10s rear cassette (IRD, not
ShimaNO).
Works like a champ, shifts perfectly. *I would suspect that you could
do the same with the 7700SS.

As a side note, I used the same setup (50/34 with 11-32 cassette)
with
campy gear and the rear der (Centaur long cage) worked fine without
touching the B screw or having to severely reduce the chain length to
get the top jockey wheel to clear the cassette.

Reason #764 why campy road gear is the clear choice for road use.

D'ohBoy

With a longer B screw screwed out the angle of the 7700 SS becomes
too
horizontal and won't hit the stop on my frame. *But I'll revisit that
solution,
possible I can get another millimeter or two out of it which may just do
it.

Sorry - that was a 7800GS Rder i did that with. *But the geometry and
cage are the same.

D'ohBoy

OK, thanks. *The Longer cage of the GS probably makes a difference. *I
have another bike with an Ultegra RD6500GS and it works fine in an 8-
speed setup with a 50/34 crank and 11-28 in back. *Guess I'm stuck on the
50-11 high to the 34-28 low, seems to suit all situations. *50-12 just isn't
high enough but I will admit to occasionally wishing I had a bail-out 34-30

If there is no other way, grind the tips off a 34, it's not as if you
willl be using it often, plus the wear rate of a large sprocket is
much much slower than say a sprocket half its size. If you think wear
would be a problem with this large sprocket, use an older, thicker
sprocket with the tips ground off.

TJ

On Mar 26, 12:29*pm, Nick L Plate wrote:
On 26 Mar, 00:39, RS wrote:



In article 25c76e6e-b9dd-46dd-8839-
,
says...

On Mar 25, 12:22*pm, RS wrote:
In article 72481d88-a31b-4cbe-a4ec-
,
says...

On Mar 22, 4:22*pm, RS wrote:
I use a Shimnao Compact Crank 50/34 w/ 9 speed setup, 11-28 in
rear.
*I'm
currently using a DA7700SS RD. *I know the max. capacity of this
derailleur
is 27 and there is minor contact even with the B screw set in all the
way and
I even exchanged the B screw for another one with 1mm longer
reach.
*Will
going to the GS version of this Derailleur solve the problem, though
I
only
hear the contact when I have the bike on my workstand, riding it
never
seems to be a problem. *I believe the GS version also states 27T
max.
in
rear but has a larger overall capacity.

And yes at my age and weight and local steep hills the 34-28 is nice
and
needed. *Thanks.

I put a B screw with about 4 mm greater length in a 7700GS RD and
it
was used with a 50/34 and 11-32 10s rear cassette (IRD, not
ShimaNO).
Works like a champ, shifts perfectly. *I would suspect that you could
do the same with the 7700SS.

As a side note, I used the same setup (50/34 with 11-32 cassette)
with
campy gear and the rear der (Centaur long cage) worked fine without
touching the B screw or having to severely reduce the chain length to
get the top jockey wheel to clear the cassette.

Reason #764 why campy road gear is the clear choice for road use.

D'ohBoy

With a longer B screw screwed out the angle of the 7700 SS becomes
too
horizontal and won't hit the stop on my frame. *But I'll revisit that
solution,
possible I can get another millimeter or two out of it which may just do
it.

Sorry - that was a 7800GS Rder i did that with. *But the geometry and
cage are the same.

D'ohBoy

OK, thanks. *The Longer cage of the GS probably makes a difference. *I
have another bike with an Ultegra RD6500GS and it works fine in an 8-
speed setup with a 50/34 crank and 11-28 in back. *Guess I'm stuck on the
50-11 high to the 34-28 low, seems to suit all situations. *50-12 just isn't
high enough but I will admit to occasionally wishing I had a bail-out 34-30

If there is no other way, grind the tips off a 34, it's not as if you
willl be using it often, *plus the wear rate of a large sprocket is
much much slower than say a sprocket half its size. *If you think wear
would be a problem with this large sprocket, use an older, thicker
sprocket with the tips ground off.

TJ

Do you understand bicycles at all? Grind the teeth off the cog so the
upper pulley doesn't hit it? YGBSM. How about making the chain the
right length or a longer b limit screw, instead of asking for a chain
slip, while going up hill, to take one's front teeth out.