Rear brake internal cable, help!

[Pikey]

Ok, it's my first bike with internal cabling so sorry if it's a newb question...

I'm building up a synapse alloy frame with internal cabling, all fine until I got to the rear brake. It's all connected now but the lever has more friction than I'd like and I can hear a faint rubbing sound. The brake return is fine and the cable outers were cut with proper snips and the ends lovingly dremelled to perfection.

My fear is, as the cable is naked as it were in the frame that it is sawing away at it in some hidden rub location - am I being paranoid? Is the rubbing just a resonant sound from the cables running throughout the outer?

It did have a big old length of plastic liner through the two ports for the rear cable, really handy for installation, that was to be taken out after the cable went through right!???

I suppose I could trim the liner done and run that accross the naked section?

Any advice would be massively appreciated (even if it's stop worrying you tart).

 

[youngoldbloke]

Don't know about the Synapse, but on my Rose the rear brake cable outer is unbroken, unrestricted, continuous all the way through the frame and out again.

 

[Pikey]

Don't know about the Synapse, but on my Rose the rear brake cable outer is unbroken, unrestricted, continuous all the way through the frame and out again.

Think you might have just solved the problem, indirectly, but you shall have the credit!

After what you said I took the cabling out and had a got poke around in there with a torch and there are these little internal cable guides just inside the ports in the frame like you would get on the outside of bikes normally, suggesting that he cable outer should stop there and bare cable run through the frame.

Well after all that, put it back together and it seems fine now, maybe the cable end ferrules weren't seated in the guides correctly or something, but it all seems fine now.

Cheers for the suggestion and getting me to fix it lol

 

[Globalti]

Synapse has a pretty straight top tube so it's more likely to be resonance. Whatever it is, you might hear the cable twanging inside the frame when you go over bumps so it wouldn't do any harm to slip a couple of those little clear plastic doughnuts or some of that plastic sleeve over the cable. They might damp the resonance as well.

While you've got the cable out, try giving it a polish with wire wool and some Brasso then drying it and lubing it very lightly by wetting your fingers with some dry chain lube. Also, how direct is the little loop of cable between the rear brake and the exit from the frame? It has to be just so - not too long or too short.

Note for bike bodgers: with increasing numbers of bikes having internal cables the bodger's life can be made easier by acquiring some copper brake pipe from your local hydraulic specialist. Sometimes it is called "cunifer" (copper-nickel-iron) pipe. You can use this to pass cables through the frame as you can put a little bend in one end and it will conform with a curved tube quite easily.

 

[fossyant]

Did you run the cable through the liner. If you could I'd be tempted to leave it on. You can always snip the end cap off the cable and run the liner back on.

 

[fossyant]

Two of my road bikes have internally routed cables - nothing new as they are over 20 years old. The Ribble has a tube that accommodates the cable and outer, so an unbroken run. The Herety has a smaller diameter tube that the outer terminates at each end of the top tube.