Cable Discs - best cable to use?

leonlikestrees

Hi all,

I've got cable discs on my new cross bike: TRP Spyre calipers, with SRAM Force brifters.

I set them up with Jagwire Racer compressionless outer. The performance wasn't great from new, and now is pretty terrible. It's a continuous run, and the rear caliper is mounted inside the rear triangle.

The problems I think are 2-fold:

• housing is very stiff, so hard to get smooth lines, especially where the housing goes into the caliper
• the housing is pointing "up" where it enters the caliper, so I think it just fills up with water and filth (this is CX, remember)

So, the perfect solution is a 100% sealed, compressionless, and highly flexible cable, but I don't know any of those!

I've always thought that compressionless outer is really important with continuous outer, but I don't know. Is that just a myth? Would Shimano SLR do the job just as well?

Any recommendations?

Thanks,

Leon

veronese68

Compressionless is better, but not essential. I ran mine on BB7s with standard outer that cam with the groupset. I run XTR gear cables on my CX now and they have quite long sealing bits on the ends of the outers. if the brake cables are similar they might do the job.
What do you mean when you say performance is terrible? Are you pulling the lever back to the bars? Is it definitely the cable? It's quite easy to glaze the rear pads if you don't use them hard every now and then. If you only use them gently performance can drop off. Pull on them hard every now and then to stop this. To get rid of it now if that is the problem do a few repeated stops from speed using the back brake as hard as you can without locking up. Basically bedding them in again.

leonlikestrees

performance is almost entirely down to cable friction. It's a lot of effort to pull the levers. I think until I sort that out, I can't tell if there are other issues (but I don't think there are)

Leon

arthur_scrimshaw

Is the rear brake the problem or both? I've got Avid bb5s on my bike, the front is pretty good but the rear brake is poor, the setup sound just like your description, the rear is mounted in the triangle, cable entry awkward and open to the elements. Agree that cable friction is a problem but also cable stretch because it's such a long run. I plan to go hydraulic if I can, I think it's the best long term solution.

leonlikestrees

front is acceptable, but not great, but then I'm using standard outer there as it was all I had.

Rear is the problem though. Full hydraulic is the dream, but I specifically built it up cable, waiting for hydraulics to get a bit cheaper!

ugo.santalucia

I've always used the cheapest stuff available (Transfil) and I've never had a problem... yes the rear is always slightly spongier, but those on 50 quid compressionless cables don't feel it slightly spongier anyway?

I can't really drag myself to spend money on a stupid plastic pipe to be honest... standard outer cable works just fine

leonlikestrees

I didn't spend £50! You can always pick up Jagwire sets (complete brake and gear) on ebay for about £20. I've been happy with them on previous bikes, but just not working on this.

I may as well just try cheap cable - it won't cost a lot to find out if it's better or not

mikenetic

If it's friction then could you try the new Shimano low-friction cables and standard outers with SRAM levers? They are designed to cope with internal cable routing so might alleviate some of the symptoms you describe.

The one thing that's missing on the Spyres is any form of tension adjustment on the caliper arm. Besides that, I've used them on a couple of bikes, and found them to an excellent brake.

bikaholic

The best cables are the Gore Ride-On Sealed Low Friction cable system (not the road bike specific version) - I use them for dream builds.

For everything else, I use ordinary spiral-wound brake outers cut from 30m rolls and ordinary peardrop stainless steel inners.

The trick with the rear brake is to keep the last third of the cable run as straight as possible and to make sure that the inner cable is under tension (ie connected to the caliper) before you do the bar wrap and clip the outer to the frame.

A note about doing the bar wrap: tape the outers securely to the bar so that there is no flex (when the brake is operated) under the area to be wrapped.

And, do the loop around headtube cable routing if at all possible.

cycleclinic

Jagwires new Road Pro XL compressionless cables are probably the best but cheaper transfil do the job well if you don't mind a bit of sponginess in the lever.

meanredspider

bikaholic wrote:

The best cables are the Gore Ride-On Sealed Low Friction cable system (not the road bike specific version) - I use them for dream builds.

Yes - I have them on the Volagi (and used the gear cables on the MTB) - excellent. I thought a Gore had stopped making them though (last I heard).

Cable friction issues are likely to be the cable runs (too tight) rather than the housings I'd have thought

rafletcher

Gore no longer make the Ride-on cable sets. I've successfully used Shimano PTFE coated cable sets (inners and outers) and I've use Shimano PTFE coated inners in BF Goodrich outers. Both worked equally well.

leonlikestrees

Hi all,

It's definitely the cable run, not the housing causing the issue - but as I stated, the problem is that the compressionless housing I've got is very inflexible, which makes the issue worse.

So, since there's a race at the weekend, I went to the LBS for some "standard" outer. They only had Shimano posh stuff @ £4 per metre off the reel (ouch!).

I installed without routing the cable, just to remove all the friction. It worked. I am aware of the compression in the cable though, as it's left a slightly spongy feel to the brake. I will put up with this until I next need to replace though. I'm not binning £8 of cable just for that!

To solve the mud issue, I've used one of these I had lying around:



and combined with one of these, actually designed for gear, so a super snug fitting:



I'm hoping this will keep the filth out. I've since clipped the cables onto the frame, and it's still good. I will take care when I tape to the bars.

As an aside, I was compounding the poor performance with poor caliper setup too. I hadn't taken very much care, and had the pads too far from the rotor, then compensating with cable adjustment. This is NOT the way to do it! Now i've got the pads as close to the rotors as I can, and no need to use the barrel adjusters. This gives much more power. So now, the combination of ok rear cabling, and better setup calipers has transformed them. I can stop trying to figure out what to sell to upgrade to hydraulics now ;-)