Cable casing issue

[Duckfoot1606]

So I’m 99% complete on my Elan bike build , very happy with how things of gone but I have a niggly problem with the rear brake.

The cable disc brake actuation feels very ‘draggy’ and I can’t get much braking at the rear. I’m using the same 5mm casing as I used on the front, where the actuation is lovely and smooth. On the rear, something isn’t right and I can feel it though the brake lever.

I’m suspicious I need to review the cable routing, is there anything else obvious I should have seen but haven’t?

Thanks in advance

A

[robgul]

Three comments:

Check that the entry points to the outer are nice and "open" with no friction on the inner. Poking a spoke into the inner works to open it

Check that the hole in the cable outer ferrule isn't too tight on the inner (ditto spoke, or a point of some sort)

. . . and I always give a squirt of GT85 into cable outers then push the inner through with a pushing and pulling movement.  (People may argue about this, but it works for me)

[Paul H]

With new kit, can you be 100% sure it is the cable?  Have the pads been properly bedded in?  I find the rear always feels less good than the front,  that shouldn't stop it working fine.
What cable is it? Compressionless works better for some brakes, you'll notice that more on the longer run to the back.  Then it's worth making sure the ends are perfectly square and using good quality ferrules. 

[Kim]

Three comments:

Check that the entry points to the outer are nice and "open" with no friction on the inner. Poking a spoke into the inner works to open it

Check that the hole in the cable outer ferrule isn't too tight on the inner (ditto spoke, or a point of some sort)

. . . and I always give a squirt of GT85 into cable outers then push the inner through with a pushing and pulling movement.  (People may argue about this, but it works for me)

I'll add "kink on the inner wire" as the other thing to check for.  Not sure how you'd manage that on a new build, but maybe something got accidentally clamped in a workstand or something.

[robgul]

Three comments:

Check that the entry points to the outer are nice and "open" with no friction on the inner. Poking a spoke into the inner works to open it

Check that the hole in the cable outer ferrule isn't too tight on the inner (ditto spoke, or a point of some sort)

. . . and I always give a squirt of GT85 into cable outers then push the inner through with a pushing and pulling movement.  (People may argue about this, but it works for me)

And more . . .

I have a useful cable tool from Elvedes (their blurb):
 
Cable Pricker  -  The cable pricker is just one of Elvedes’ handy inventions. After cutting the outer cable, you can use the Elvedes cable pricker to close and re-open this in a professional way. This means that the cable casing can be easily mounted to the outer cable and the inner cable required little effort to reach the outer cable. This cable pricker is suitable for outer cables of both 4.9 mm and 4.1 mm.

Cut the outer and poke it into the approrpriate end of the tool and give it a twist - the pointed pin opens the inner hole and tidies up the cut end.   Works a treat.  Not cheap at about £30 (mine was a freebie at a cycle trade show )   

[Kim]

Cute.

TBH, I find the worst of the problem can be mitigated by cutting the outer with a bit of sacrificial inner in place.

[Duckfoot1606]

Thanks for the thoughts, some possibilities I hadn’t considered so I will have another go later

A

[robgul]

Cute.

TBH, I find the worst of the problem can be mitigated by cutting the outer with a bit of sacrificial inner in place.

That was my "pre pricker" method but sometimes meant a lot of poking about, shaking the outer to get the bit of inner out.   

The other oft-quoted cable tip is coating the inner where it's to be cut with superglue to deter fraying . . . .  and did i mention I have a cable end-cap crimper tool?  - another useful item if you're doing lots of workshop stuff*

*with the closure of three nearby LBS locations and the large motor and cycle parts emporium in the town I seem to be getting more and more bike service and repair customers beating a path to my door

[Kim]

a cable end-cap crimper tool?  - another useful item if you're doing lots of workshop stuff*

You know those terrible wire stripper/crimping tools you get from the automotive wiring section of Halfrauds?  End-caps are the one thing I've found that it's any good for, so it now lives in my bike tools box, well away from anything electrical.

[robgul]

a cable end-cap crimper tool?  - another useful item if you're doing lots of workshop stuff*

You know those terrible wire stripper/crimping tools you get from the automotive wiring section of Halfrauds?  End-caps are the one thing I've found that it's any good for, so it now lives in my bike tools box, well away from anything electrical.

I graduated from one of those . . . running a bike shop for 3 or 4 years made it very tempting to purchase the best tools for the job for your own workshop.

[Kim]

Yeah, fair enough.  If you're doing it all day, you want the best.

Actually, I've got a tool for bootlace ferrules that would probably do a lovely job on end caps.  Must give it a go...

[Polar Bear]

I had to Google "bootlace ferrule" because I thought that the tight sleeve at each end of a bootlace is called an aglet.

And yes, bootlace ferrules are entirely different.  Today is a skewl day.  👍

[Feanor]

The Park cable cutters also have a crimping jaw in them...

https://www.parktool.com/en-int/product/professional-cable-and-housing-cutter-cn-10

[D.A.L.E.]

The Park cable cutters also have a crimping jaw in them...

https://www.parktool.com/en-int/product/professional-cable-and-housing-cutter-cn-10

Knipex equivalent do too and they are better and cheaper. Say no to Park Tool.

[D.A.L.E.]

The other oft-quoted cable tip is coating the inner where it's to be cut with superglue to deter fraying . . . .

If someone found out I'd done that, I think I'd die of embarrassment.

and did i mention I have a cable end-cap crimper tool?  - another useful item if you're doing lots of workshop stuff

Mine stamps my initials on the crimp. Game changer.

[Duckfoot1606]

Sorted, although im not entirely certain what happened but in the end i have swapped out the casing for a new length and its butter smooth now with the added bonus that ive got a functional rear brake now.

Thanks for the help

A

[Kim]

And yes, bootlace ferrules are entirely different.  Today is a skewl day.  👍

Yep.  They're the things that let you stick wires (stranded, electrical) into adjacent terminal blocks without an unseen stray strand inevitably shorting something out and causing bad swears, magic smoke release, or even DETH.  (Plus the connections don't become looses-goosey over time the way they do when tinned with solder to prevent fraying.)

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