Internal Cables Shifting Problem with Rear Derailleur

pprendeville
pprendeville Posts: 51
edited February 2015 in Workshop
Had posted up on this forum recently about a problem I was having when shifting in the big ring. Got it sorted but now I'm having a new problem which is even more annoying.

It all started when I was fiddling around with my mudguards. I commute most days on the bike and they are essential. They're the Crud brand and were rubbing a bit off the rear wheel so I put a cable tie in through the mudguard and round the seat tube. Only problem was I wrapped it round the front derailleur cable in the process and didn't realise it. Big ring shifting was impossible so I started fiddling round and ended up adjusting rear derailleur also before I realised my mistake (cable tie creating additional tension on front derailleur cable).

Anyway, long story short, since that episode the front derailleur is fine since properly mounting the cable tie but the rear derailleur is giving serious issues. It's almost as if the cable is stuck on something internally (internal cable routing). Very tight when shifting from small to big cogs and needs a lot of finger pressure to move the right hand lever. I'm using Dura Ace 7900.

I have re-routed the cables about 5 times ensuring they are not crossing. I use a telescopic magnet to bring them through the down tube so I'm certain they are not. there was a creaking noise when shifting from small cogs to big which I've eliminated. I'm using Shimano inner and outer cables/ferrules and have even greased them (they're already PTFE coated). Still not shifting properly. I'm wondering is it something to do with the cable guide under the BB. On a sidenote, does anyone know where I could one that looks like this? It's off a Chinese frame FM066. They're all closed there for Chinese New Year so I don't have a chance of getting in touch with them for another few weeks (have sent off an email alright). Can't find anything on eBay. Just want to get a spare one to eliminate possible causes one by one. Have also ordered new cables (inner and outer today) today.

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Comments

  • trailflow
    trailflow Posts: 1,311
    I have the same frame and i also had grief with the integrated bb guide. Mine was poorly done and there was excess resin/glue under the guide which caused it to pop up more than it should. With the guide installed It was causing the sides to trap the cables against the frame. I tried to file it down underneath the best i could but still had crap shifting. In the end i just removed it completely and used 2 small pieces of outer. Plastic straws/tubes also work. Front and rear shifting is alot smoother.
  • Right, that's interesting. I have never had the problem up to now so I find it strange. Any chance you could post a photo? thanks for the feedback.
  • trailflow
    trailflow Posts: 1,311
    qjBxaC1.jpg
    Im currently using a rear powercordz cable thats why they are different.
  • Cheers for that. Do you just block it up with masking tape or something?
  • trailflow
    trailflow Posts: 1,311
    Nope. Just leave it as it is. i dont ride in wet weather if i can help it. Now you have suggested it i may try that.