Spyre trp c Freezing

I had this issue a few years ago, and tried a couple of things before I got one that worked well.

Again...it's the blob of grease.

However, what I eventually did was fill a long V brake boot with grease and slide that over the cable between bolt and adjuster. It just sits there as there's no way to secure it, but it's kept the rear brake working through 2 winters.

The new Spyres have addressed the issue and have a little nipple on the end of the adjuster bolt allowing you to secure a boot.

After applying the blob of grease it would, I think be useful to have a little length of Woods valve rubber to fit over the outer / inner transition. Might work, worth a try for just a few pennies.

https://www.sjscycles.co.uk/inner-tubes/valve-rubber-for-woods-valves/

Previous thread about this here - yep getting grease is about the only thing that seems to work. Applied to both TRP Spyre and HY/RDs as well. Its almost like they didnt test them in freezing conditions. 

https://road.cc/content/forum/213375-trp-rear-spyre-and-hyrds-freezing-a...

I totally agree  with Mike the Bike above: I had the same issue and came to the same conclusions...except I didn't have the genius blob of grease idea

I tried making a boot to cover the ferrule on the end of the outer (just where it went into the last cable guide on the frame before the brake and emerged as a naked wire.) from a bit of inner tube and a cable tie or two(not pretty, but...) it must have stopped some of the moisture running in there...worked for a bit, but captured lots of mud and crud, and ultimately, looked rubbish and the cable wore through it after a few weeks taking me back to square one!

I also tried squirts of WD40 and GT85 down the inner...difficult to tell how effective really but certainly not 100%.

The blob of grease thing sounds like a much more simple and effective cure...I wish I'd thought of that: I'm going into the shed to do it right now!

On the plus side...your cable discs will be fine in the heat whereas the fluid in the hydro's expands and jams the brakes on like it occasionally does on my MTB...!

Your sad tale reminds me of the old Chinese proverb.  It's the cable.  It's always the cable.  And when you know it's not the cable, it's the cable.

I've suffered from this rear-brake icing on three seperate bikes over the years.  It only happens with cable discs and it's invariably the back brake that plays up.  And that's because of the way the cable dips downwards, alongside the chain stay, on its route to the calliper.

Condensation, or maybe rain, collects inside the outer cable at its lowest point and freezes when it's cold enough.  The pressure of your hand on the lever is sufficient to move the cable in one direction and apply the brakes but the flimsy pad return spring can't overcome the ice to release them.

To prevent water entering the outer I fitted a rubber boot to the cable at the point where the inner emerged from the outer.  It only cost about twenty pence from my LBS and it was completely and totally useless.  Water soon found its way along the strands and into the outer.

So I tried again and smeared a blob of thick grease at the same point and each week, after I'd washed the bike, I'd carefully replace the blob. Success, the water couldn't find a way in.  Blob 1 ..... Ice 0.

It's worth a try and good luck.

(This problem only surfaced comparatively recently when manufacturers moved the position of the calliper to the chain stay.  In the days when they were invariably bolted to the seat stay, the cable run was downhill and straight, with no hiding place for water.  Another example of progress?)