Here is a snapshot from our daily work.
Take a look.
This photo shows the underside of the bottom bracket on a road bike frame. It’s a bit hard to tell, isn’t it?
Let’s zoom in.
This is where the cable exits the frame.
Due to years of use, the cable has been rubbing against the frame, causing the material to wear down.
While the frame won't break immediately, it will continue to erode little by little if left as is.
It also increases friction, so there’s really no upside to this.
So, we add a little trick when replacing the cable:
we feed a thin straw through the opening.
It looks like this.
It may seem like a very simple step, but this one adjustment prevents the frame from wearing away and helps the cable move more smoothly.
It’s a very useful tip, especially these days when internal cable routing has become so common.
If you replace your own cables, I highly recommend giving this a try.