Rear disc brake - TRP Spyre

dinyull

Been going round in circles with this annoying nagging problem.

Whenever I use the rear brake, the caliper won't return to the original position meaning I start getting a lot of travel in the brake lever and the read brake drags.

Because of this a few months back I serviced the caliper, took it apart and re-greased everything thanks to some instructions from another thread on here.

This didn't solve it.

I then replaced the inner and outer cable and hey presto, problem solved. However, few months down the road I'm suffering the same problem.

Obviously I need to change the cables again, but can't help but think I shouldn't have to do this every few months.

I'm using Jagwire compassionless cables and only have this problem with the rear. Anyone else had this problem and found a way to solve it?

timothyw

It might be that whoever fitted the new cables and outers didn't do a brilliant job and there is a pinch point somewhere that is stopping the free movement of the cable.

You can verify what is causing the problem quickly just by releasing the clamp bolt on the brake caliper - if the caliper returns cleanly once the cable is disconnected then you know that the cable run is the problem.

Honestly though, a few months usage might be all you get if those months were through slush, grit salt and wet mud - part of the reason that hydraulics are so prized is because there is no way for contamination to get into the hose, whereas cable brakes by their nature draw a little bit of gunk into the outer each time the brake is used.

You might want to look into the 'sealed' cable systems that are out there - https://www.bikeradar.com/gear/article/ ... les-28687/

veronese68

Dinyull wrote:

I'm using Jagwire compassionless cables and only have this problem with the rear. Anyone else had this problem and found a way to solve it?

Not had that problem but suspect it's muck getting into the cable making it sticky. Can you run full length outer so the dirt and muck can't get in? How does the caliper mount on your frame? could water run down the cable and into the outer at that end? That can be a problem with calipers mounted in the rear triangle. Some cables have better sealing than others on the ferrules at the ends of the outers, that might help. Personally I don't grease or oil my cables as dirt tends to stick to it and make things worse.
Link above about sealed cables is the kind of thing, don't think Gore do their cables any more. My gear cables are Shimano XTR which don't have the full length liner but do have much better seals than standard ones, there may be something similar for brake cables.
Edit: Looks like Jagwire Elite are sealed.

dinyull

Veronese68 wrote:

Not had that problem but suspect it's muck getting into the cable making it sticky. Can you run full length outer so the dirt and muck can't get in?

Already full length.

Veronese68 wrote:

How does the caliper mount on your frame? could water run down the cable and into the outer at that end? That can be a problem with calipers mounted in the rear triangle.

Post mount. And yes, water could run down as the cable is angled up into the caliper.

dinyull

TimothyW wrote:

You can verify what is causing the problem quickly just by releasing the clamp bolt on the brake caliper - if the caliper returns cleanly once the cable is disconnected then you know that the cable run is the problem.

Tried that and although the caliper won't return fully, it's nowhere near as bad as when the cable is connected. Was like this from when I serviced the calipers and the same front and back.

TimothyW wrote:

Honestly though, a few months usage might be all you get if those months were through slush, grit salt and wet mud - part of the reason that hydraulics are so prized is because there is no way for contamination to get into the hose, whereas cable brakes by their nature draw a little bit of gunk into the outer each time the brake is used.

Yep, it's on the winter/commuter so it's had a hard winter.

veronese68

Dinyull wrote:

Post mount. And yes, water could run down as the cable is angled up into the caliper.

Probably damp in that end of the cable then. As you won't need a full cable set do you have a friendly LBS you can talk to that might have some spare ends knocking around in the workshop?
This is what the XTR ends I have look like

dinyull

Veronese68 wrote:

Dinyull wrote:

Post mount. And yes, water could run down as the cable is angled up into the caliper.

Probably damp in that end of the cable then. As you won't need a full cable set do you have a friendly LBS you can talk to that might have some spare ends knocking around in the workshop?
This is what the XTR ends I have look like

I might have some of those knocking about in the garage - which I obviously should have been using in the first place :oops: haha.

Cheers

veronese68

Dinyull wrote:

I might have some of those knocking about in the garage - which I obviously should have been using in the first place :oops: haha.

No problem. Even better if you have some, my garage is a bit like that too. You should get it all sorted in time for some decent weather then. Assuming we are going to get some decent weather that is.

6wheels

If the problem is marginal-as it seems- is it possible to spread the return springs or obtain stronger ones? I've had Spyres on my wet bike for three years and they've been pretty good.