DuraAce RD-7800-GS Derailleur Cage Issues
09-19-24, 11:44 AM
#1
DuraAce RD-7800-GS Derailleur Cage Issues
Hi all,
Recently managed to get a 7800 GS rear derailleur, why are they so rare? It was a bit manky, cage return was gritty, so I took it apart to clean it and add some fresh grease and a set of pulleys I had in my parts bin off a discarded Ultegra R8050 Di2. The pulleys fit just fine, btw.
After a few failed attempts to re-install the cage, I seem to have overtightened the P knuckle spring and bent it. At first I panicked a little, as you do, then realised the inner cage spring catch hole seems to be offset compared to the hole on the other side of the cage. Oh yeah, the spring is no longer available, before I get too deep into finding a replacement, I would like to make sure the cage is alright.
IMO, the hole would need to be all the way through the cage, in order for the spring to be secured properly at both ends when tensioning the cage, without any risk of slipping out of the hole. I've added some pictures of my cage and what I could find online, however, no pictures available of the GS cage, only a couple technical drawings and a couple pictures of the SS cage I found on google. The SS cage spring catch hole is clocked differently and seems to be a through hole. The shape of the spring would match the outer spring hole location, as the inner spring mount is almost 180° off. Me overtightening it would make sense in that case.
My question is, does anyone have a GS cage, or a GS derailleur they can take some pictures off? it should be obvious without removing the cage, so I can check if my spring stop has slipped or if I'm just imagining things. Any help is greatly appreciated.
Recently managed to get a 7800 GS rear derailleur, why are they so rare? It was a bit manky, cage return was gritty, so I took it apart to clean it and add some fresh grease and a set of pulleys I had in my parts bin off a discarded Ultegra R8050 Di2. The pulleys fit just fine, btw.
After a few failed attempts to re-install the cage, I seem to have overtightened the P knuckle spring and bent it. At first I panicked a little, as you do, then realised the inner cage spring catch hole seems to be offset compared to the hole on the other side of the cage. Oh yeah, the spring is no longer available, before I get too deep into finding a replacement, I would like to make sure the cage is alright.
IMO, the hole would need to be all the way through the cage, in order for the spring to be secured properly at both ends when tensioning the cage, without any risk of slipping out of the hole. I've added some pictures of my cage and what I could find online, however, no pictures available of the GS cage, only a couple technical drawings and a couple pictures of the SS cage I found on google. The SS cage spring catch hole is clocked differently and seems to be a through hole. The shape of the spring would match the outer spring hole location, as the inner spring mount is almost 180° off. Me overtightening it would make sense in that case.
My question is, does anyone have a GS cage, or a GS derailleur they can take some pictures off? it should be obvious without removing the cage, so I can check if my spring stop has slipped or if I'm just imagining things. Any help is greatly appreciated.
09-19-24, 02:39 PM
#2
Hi all,
Recently managed to get a 7800 GS rear derailleur, why are they so rare? It was a bit manky, cage return was gritty, so I took it apart to clean it and add some fresh grease and a set of pulleys I had in my parts bin off a discarded Ultegra R8050 Di2. The pulleys fit just fine, btw.
After a few failed attempts to re-install the cage, I seem to have overtightened the P knuckle spring and bent it. At first I panicked a little, as you do, then realised the inner cage spring catch hole seems to be offset compared to the hole on the other side of the cage. Oh yeah, the spring is no longer available, before I get too deep into finding a replacement, I would like to make sure the cage is alright.
IMO, the hole would need to be all the way through the cage, in order for the spring to be secured properly at both ends when tensioning the cage, without any risk of slipping out of the hole. I've added some pictures of my cage and what I could find online, however, no pictures available of the GS cage, only a couple technical drawings and a couple pictures of the SS cage I found on google. The SS cage spring catch hole is clocked differently and seems to be a through hole. The shape of the spring would match the outer spring hole location, as the inner spring mount is almost 180° off. Me overtightening it would make sense in that case.
My question is, does anyone have a GS cage, or a GS derailleur they can take some pictures off? it should be obvious without removing the cage, so I can check if my spring stop has slipped or if I'm just imagining things. Any help is greatly appreciated.
Recently managed to get a 7800 GS rear derailleur, why are they so rare? It was a bit manky, cage return was gritty, so I took it apart to clean it and add some fresh grease and a set of pulleys I had in my parts bin off a discarded Ultegra R8050 Di2. The pulleys fit just fine, btw.
After a few failed attempts to re-install the cage, I seem to have overtightened the P knuckle spring and bent it. At first I panicked a little, as you do, then realised the inner cage spring catch hole seems to be offset compared to the hole on the other side of the cage. Oh yeah, the spring is no longer available, before I get too deep into finding a replacement, I would like to make sure the cage is alright.
IMO, the hole would need to be all the way through the cage, in order for the spring to be secured properly at both ends when tensioning the cage, without any risk of slipping out of the hole. I've added some pictures of my cage and what I could find online, however, no pictures available of the GS cage, only a couple technical drawings and a couple pictures of the SS cage I found on google. The SS cage spring catch hole is clocked differently and seems to be a through hole. The shape of the spring would match the outer spring hole location, as the inner spring mount is almost 180° off. Me overtightening it would make sense in that case.
My question is, does anyone have a GS cage, or a GS derailleur they can take some pictures off? it should be obvious without removing the cage, so I can check if my spring stop has slipped or if I'm just imagining things. Any help is greatly appreciated.
The position of the 'hole' in your 1st pic seems to match with the diagram from Shimano.
