Who knows. At a guess, I'd say they were trying to reduce the length of cable outer from the frame to the derailleur and also angle the arc of the outer so that it sits nearer to the frame. The Ultegra model I was working on had another gobsmacking piece of bad redesign: a flimsy barrel tension adjuster that's incredibly easy to knacker when turning it under stress (as the previous mechanic had helpfully already done for me). I replaced it with an old-style adjuster from a 105 derailleur. Again Shimano obviously know there's a problem, as the installation instructions specifically say to use a metal (not plastic) ferrule with it. As the metal ferrules are usually slightly thinner and cause less friction, that reduces the chances of accidentally breaking the adjuster by forcing it.
Tiagra Rear Derailleur Repeated Cable Fraying
Re: Tiagra Rear Derailleur Repeated Cable Fraying
Re: Tiagra Rear Derailleur Repeated Cable Fraying
It looks as if the RD is bent where the cable exits from the adjuster arm. My 4700 GS mech is shown bottom here.
Re: Tiagra Rear Derailleur Repeated Cable Fraying
The reason for the more extreme angle of cable exit is, I think, the greater cable pull of Shimano's 11 speed rear derailleurs, which the 4700 10 speed rear derailleur shares.
I suspect that Shimano may have determined by testing that the cables will fray in the STI shifter before they will fray at the rear derailleur (possibly providing the 'cover with tongue' is fitted), assuming normal use, i.e. not riding excessively in smallest or largest sprockets, such as riding cross chained.
I suspect that Shimano may have determined by testing that the cables will fray in the STI shifter before they will fray at the rear derailleur (possibly providing the 'cover with tongue' is fitted), assuming normal use, i.e. not riding excessively in smallest or largest sprockets, such as riding cross chained.
Re: Tiagra Rear Derailleur Repeated Cable Fraying
My 11 speed 105 rear mech' cable exit isn't as severe as that.
Not sure, but if the derailleur hanger is bent would that have an effect on the angle of the parallelogram ?
11 speed cassette width fits in a 10 speed space so the mech' movement isn't any wider.
I would check the hanger setting.
I really wouldn't expect the cable to rub on the exit thread but neither can I see the casting being bent to cause this. I think casting would crack if it got bent.
Not sure, but if the derailleur hanger is bent would that have an effect on the angle of the parallelogram ?
11 speed cassette width fits in a 10 speed space so the mech' movement isn't any wider.
I would check the hanger setting.
I really wouldn't expect the cable to rub on the exit thread but neither can I see the casting being bent to cause this. I think casting would crack if it got bent.
You'll never know if you don't try it.
Re: Tiagra Rear Derailleur Repeated Cable Fraying
Don't get me started on the fraying cables in the STI lever. "Hey, I know, let's route the cable through a sharp right-angled bend inside the lever where no-one can see it fraying and all the fragments will get stuck in the mechanism, that sounds like a good idea..."slowster wrote: ↑13 May 2022, 10:45am I suspect that Shimano may have determined by testing that the cables will fray in the STI shifter before they will fray at the rear derailleur (possibly providing the 'cover with tongue' is fitted), assuming normal use, i.e. not riding excessively in smallest or largest sprockets, such as riding cross chained.
Re: Tiagra Rear Derailleur Repeated Cable Fraying
It looks like we are in accord here.
OP's looks bent.
Mick F. Cornwall
Re: Tiagra Rear Derailleur Repeated Cable Fraying
Nailed it!
The hanger for the adjuster is bent......it had already occurred to me that I would be looking at re-drilling it to get a straighter cable run.....probably wouldn't get a useable thread, but a nut will do.
unless its the arm for the pinch bolt which is bent? need to get it next to a straight mech. to be sure!
Bike fitting D.I.Y. .....http://wheel-easy.org.uk/wp-content/uploads/bike-set-up-2017a.pdf
Tracks in the Dales etc...http://www.flickr.com/photos/52358536@N06/collections/
Tracks in the Dales etc...http://www.flickr.com/photos/52358536@N06/collections/
Re: Tiagra Rear Derailleur Repeated Cable Fraying
I don't think that the part of the casting for the adjuster is bent. The GS (longer cage) version of the derailleur is designed like that - see the image below of the SS and GS versions side by side.
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Re: Tiagra Rear Derailleur Repeated Cable Fraying
The one on mine is definitely not bent. The cable angle also gets worse when chain is in lower sprockets.
Cable end gizmo ordered! (And another spare cable)
Cable end gizmo ordered! (And another spare cable)
Re: Tiagra Rear Derailleur Repeated Cable Fraying
So, its "long cage" in order to reel in more chain from wide ratio gears.
In order to clear a bigger bottom sprocket, Shimano have angled the parallelogram so the top jockey wheel goes further down as it goes towards first gear; they have then over-compensated and angled the barrel adjuster tab too much, the cable angle in the higher gears is absurd. (in Vince's original picture)
I think i would make sure i set the gears up with that barrel adjuster "all the way out" even fitting an in-line adjuster so I had one to use "on the road" .....and Shimano's "cover with tongue". I would also check out to see if the liner from a Vee brake "flexible noodle" would fit.....i'm staggered that i have never (yet) come across one of those showing any significant wear.
There is still the possibility of re-drilling the adjuster tab, and i would consider doing that depending on the cable angle in high gears.
In order to clear a bigger bottom sprocket, Shimano have angled the parallelogram so the top jockey wheel goes further down as it goes towards first gear; they have then over-compensated and angled the barrel adjuster tab too much, the cable angle in the higher gears is absurd. (in Vince's original picture)
I think i would make sure i set the gears up with that barrel adjuster "all the way out" even fitting an in-line adjuster so I had one to use "on the road" .....and Shimano's "cover with tongue". I would also check out to see if the liner from a Vee brake "flexible noodle" would fit.....i'm staggered that i have never (yet) come across one of those showing any significant wear.
There is still the possibility of re-drilling the adjuster tab, and i would consider doing that depending on the cable angle in high gears.
Bike fitting D.I.Y. .....http://wheel-easy.org.uk/wp-content/uploads/bike-set-up-2017a.pdf
Tracks in the Dales etc...http://www.flickr.com/photos/52358536@N06/collections/
Tracks in the Dales etc...http://www.flickr.com/photos/52358536@N06/collections/
Re: Tiagra Rear Derailleur Repeated Cable Fraying
I refer you to my pictures.
Mine was a long cage and not "bent" and out of line no matter which cog or chainring (triple) was selected.
10sp 11-28 and later 12-30 as well as 61/48/34
Granted, mine was an older version.
Just checked in the workshop. I no longer have it.
Mine was a long cage and not "bent" and out of line no matter which cog or chainring (triple) was selected.
10sp 11-28 and later 12-30 as well as 61/48/34
Granted, mine was an older version.
Just checked in the workshop. I no longer have it.
Mick F. Cornwall
Re: Tiagra Rear Derailleur Repeated Cable Fraying
Can the OP buy one like that?Mick F wrote: ↑14 May 2022, 8:19am I refer you to my pictures.
Mine was a long cage and not "bent" and out of line no matter which cog or chainring (triple) was selected.
10sp 11-28 and later 12-30 as well as 61/48/34
Granted, mine was an older version.
Just checked in the workshop. I no longer have it.
Bike fitting D.I.Y. .....http://wheel-easy.org.uk/wp-content/uploads/bike-set-up-2017a.pdf
Tracks in the Dales etc...http://www.flickr.com/photos/52358536@N06/collections/
Tracks in the Dales etc...http://www.flickr.com/photos/52358536@N06/collections/
Re: Tiagra Rear Derailleur Repeated Cable Fraying
It would not work with his current shifter. 4600 uses the same cable pull as Shimano's other 10 speed road rear derailleurs and shifters, but (despite also being 10 speed) 4700 uses the same cable pull as Shimano's 11 speed road rear derailleurs and shifters.
Re: Tiagra Rear Derailleur Repeated Cable Fraying
I would echo your sentiments. I've just had one fail on me (not for the first time) this week, fortunately at home on the work stand. This is on our tandem and the last failure was about two years ago. I think I'm going to replace them annually as a matter of course. Interestingly I recently replaced a gear cable that frayed at the nipple on one of my bikes that uses bar end shifters. This is a bike that used a few times every week. The cable in question has been on it for 35 years!AndyK wrote: ↑13 May 2022, 12:32pmDon't get me started on the fraying cables in the STI lever. "Hey, I know, let's route the cable through a sharp right-angled bend inside the lever where no-one can see it fraying and all the fragments will get stuck in the mechanism, that sounds like a good idea..."slowster wrote: ↑13 May 2022, 10:45am I suspect that Shimano may have determined by testing that the cables will fray in the STI shifter before they will fray at the rear derailleur (possibly providing the 'cover with tongue' is fitted), assuming normal use, i.e. not riding excessively in smallest or largest sprockets, such as riding cross chained.
Also of note is that our tandem uses a 4700GS rear dérailleur and I've noted the angle at which the cable exits with some concern. However IME the cable fails at the lever first!
Re: Tiagra Rear Derailleur Repeated Cable Fraying
You cannot bend a casting it will snap....VinceLedge wrote: ↑13 May 2022, 7:23pm The one on mine is definitely not bent. The cable angle also gets worse when chain is in lower sprockets.
Cable end gizmo ordered! (And another spare cable)
Take a file or drill and ease the edge of the casting into a radius. The steel cable should wear the alu casting not the other way around.....