Has anyone considered that Katy Perry sings about the effects of temperature swings on your bike in the song “Hot N Cold”? It all comes together: You’re (the temperature) hot then you’re cold, you’re (my brakes) yes then you’re no, you’re (my cables) in then you’re out, you’re (my gears) up then you’re down. Yup, it checks out.
I made an effort to keep riding all through the winter. This feat involved gearing up to stay warm, and also a considerable amount of bike prep and maintenance. The temperatures remained relatively mild throughout November and December, hovering just above freezing most of the time. The day finally came, however, when the mercury was firmly in the negatives. This is what I had been waiting for; I was ready.
But my bike was not. Although a full tuneup was performed by the LBS in preparation for the colder months my Miele was hiding a dangerous secret: moisture in the brake cables. Water can creep into the cable housing while riding or even after you park if the components are wet. There’s barely any space but all it takes is a small amount of liquid. When it freezes and expands the cable is effectively strangled and cannot move. For the rider, this means no brakes.
A Rude Awakening
When I left for work that morning I noticed nothing wrong. I store my bike indoors so everything was functioning as expected, but, five minutes into my ride as I approached a red light, I pulled on my rear brake and the lever didn’t budge. It was quite unnerving. Fortunately I was able to use my front brake although it too was quite stiff. Unsure of the problem I took it easy the rest of the way.
Of course when I came home and began to investigate the problem ‘magically’ disappeared. I had a strong hunch the culprit was water and the LBS corroborated my story the following day – apparently I was not the only rider to lose their brakes when the temperature dropped. New cables with better protection went on and I never fell victim to missing brakes for the rest of the season.
Cables can also be adversely affected by a rise in temperatures. Before tackling this we must first bring up the idea of cable stretch – the settling process of a new cable as it pushes and pulls components on your bike. Whether or not the thin braided cables physically elongate, or tension forces cause small movements between the cable and the part that secures it, is up for debate.
Indisputable is the fact that I travelled to Hawaii for two weeks and returned to a significant rise in temperatures. My bike remained untouched at home during my absence. When I set off on my ride to work I could only access the top 6 gears on the back of the bike. The Shimano 105 rear derailleur could not be coerced into travelling to the bottom 5 cogs of the cassette.
Fixed With a Tuneup?
That night I played mechanic and found that, no matter the combination of high/lo limit screws, barrel adjusters, and cable tensions, I simply wasn’t able to shift through all 11 gears. The shift lever would click but the derailleur wouldn’t budge. Was the shifter to blame? Considering the parts warranty on my Miele had just expired I hoped that was not the case. Then I read about cable fatigue which explains that a well used cable can effectively lose pulling power. Typically this doesn’t happen all at once – individual strands may fail and fray over time – but can definitely be accelerated by a significant change in temperature.
After 30 minutes I gave up on my effort to fix my shifting woes with a screwdriver and decided another trip to the LBS was in order. Sure enough, once the cable was replaced I had all 11 speeds back at my fingertips.
Keep an eye on your cables; don’t let them ruin your ride. And perhaps keep your bike cleaner than I do.