Our city bike’s brake broke. The brake wire snapped clean through right when I squeezed the lever (see photo below).
The bike is over 20 years old at this point and showing its age.
The rear brake wire wasn’t far behind either, so I replaced both at the same time.
This article walks through how a non-mechanic (me) replaced bicycle brake wires on a city bike.
It also covers the tools needed and what it cost in total.
Hopefully it’s useful if you’ve been thinking about doing a brake-wire swap yourself.
Tools and Replacement Wire
Here’s what I used and the brake wires I bought.
Tools used
Three tools: a spanner (wrench), pliers, and end-cutting nippers.
The spanner is required for loosening and tightening the nuts.
An adjustable wrench you can size to the nut is the most versatile choice.
I used the pliers to crimp the wire-end cap onto the brake wire after installation.
The end-cutting nippers were for trimming the brake wire to length after installation.
Q. Can you cut a brake wire with regular pliers or wire nippers?
A. Brake wire is thick and tough, so regular pliers/nippers struggle. There’s also a dedicated cable cutter for this, but I went with end-cutting nippers and they did the job.
Buying the brake wires
Front and rear brake wires are different lengths.
I bought a 65 cm wire for the front and a 165 cm wire for the rear.
373 yen for the front, 335 yen for the rear (about $5 total).
(Bought on Amazon — links below.)
Note: city bike brake wires have a “barrel-shaped” end (like a small barbell), shown below.
Sport bikes use a different end fitting, so check yours before buying.
Here are the wires I used:
Replacing the Front Brake Wire
Tools and replacement wires ready — let’s get started.
Removing the old brake wire
Starting with the front.
Time to take out the old brake wire.
Here’s the general layout:
If your brake wire has a “wire end cap” on the tip, pull it off with pliers first before doing anything else.
Now to remove the old wire.
Loosen the nut with the spanner.
Nut loosened.
Pull the brake wire out.
At the lever side, the wire’s barrel-shaped end is just hooked into a slot.
Twist and pull to release it as shown.
Old brake wire is out.
Installing the new brake wire
Now to install the new wire.
Start at the lever side. Hook the barrel end into the slot.
Route the wire along the handlebar,
and feed it through the brake exactly the reverse of how you removed it:
With the wire threaded, squeeze both sides of the brake closed against the wheel as shown, then pull the wire taut and tighten the nut down with the spanner.
(Side note: my brake pads themselves were also visibly worn — let’s just gloss over that for purposes of this article 😅)
Squeeze the brake lever — if it travels about halfway before engaging fully, you’re good.
Last, crimp a wire end cap onto the tip of the brake wire.
(If your wire is way too long, trim it to the right length with end-cutting nippers before putting on the cap.)
Front brake wire is done.
Replacing the Rear Brake Wire
Now for the rear.
Removing the old wire
The rear brake wire attaches at the rear brake unit like this:
Same as before — if there’s a wire end cap on the tip, remove it with pliers first.
Loosen the nut that secures the brake wire.
Old brake wire pulls right out.
Installing the new wire
Install the new wire starting at the lever side.
Hook the barrel end into the lever slot, then route the wire along the frame down to the rear brake.
To secure the wire at the rear brake: pull section ① taut and tighten nut ② with the spanner.
Now check the lever travel.
About halfway is the target — mine was a bit too long, so I’ll dial it in.
Adjusting the rear brake wire
The rear brake wire has a tension adjuster.
Use the adjusting bolt + nut shown below to fine-tune.
First, loosen the lock nut with a spanner.
Next, turn the adjusting bolt to set the tension.
Once dialed in, lock the nut back down.
You’re aiming for the lever to engage at about half-pull.
Last step: crimp a wire end cap onto the tip.
My wire was way too long, so I trimmed it with end-cutting nippers.
(I tried regular pliers first — no chance, brake wire is way too tough. I’d guess regular nippers wouldn’t cut it either.)
Slide the end cap onto the tip,
and crimp it tight with pliers.
End cap secured.
That’s the rear done.
Wrap-up
Front and rear brake wires replaced on the city bike.
Total cost: 708 yen (about $5) for both wires.
Total time: about an hour.
It’s not actually that hard, and the parts are cheap. If your brake wires are getting old, definitely worth doing yourself.
(I’ve also written about replacing the bike’s hub-dynamo headlight in the past — that article is in Japanese only.)
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