Measuring spoke tension with a gauge

Replacing a spoke (again)

With the typhoon clean-up in progress throughout Tokyo, I thought this would be a good chance to fix the broken spoke. In addition to simply replacing it, of course, I wanted to make sure that the break wasn’t caused by hub damage.

Tools needed to remove sprockets and change spoke
Tools at the ready

Inner hub flange showing no damage where spoke broke
No damage on the inner flange

Outer hub flange showing scratching
Some scratching here from the earlier failure

The spoke appears to have broken right near the head, so I had a close look at the hub flange. The inner flange, against which the spoke pulls, shows no marks. There’s a shallow gouge on the outer flange from the original mangling when the chain came off into the spokes, but it felt pretty smooth to the touch.

Bicycle wheel with tire removed and rim strip partially removed
Tire and rim strip off

Broken spoke lying alongside a replacement
You’d better straighten up, young man!

Bicycle hub after broken spoke is replaced
Checking the spoke / flange interaction

To replace the spoke I had to remove the rear cassette, and then the tire, tube and rim strip. With those items out of the way, I threaded the replacement into place. Then I checked the fit of the spoke head in the flange carefully. As expected, it doesn’t touch the gouge in the outer edge of the flange at all.

(And yes, that’s still English mud there on the hub … )

Measuring spoke tension with a gauge
Checking the tension

With the spoke threaded in and properly tensioned, it was time to check the wheel trueness. The truing stand I ordered hasn’t arrived yet, so I popped the wheel into the bike frame and used my index finger to eyeball it.

With the wheel more or less true, all that remained was to remount the tire and inflate it, put the wheel on the bike a final time and check the shifting and braking. All done in almost less time than it takes to say (or it would have been, but the tire pump took a few tries to get a good seal on the valve).

Bicycle wheel and pumpBicycle wheel with tire fully inflated
Time to pump … you up!

And we’re done. I put the tools away and washed up. From the weather forecast, it may be Thursday or Friday before I have a chance to ride to work. And after that, there’s more rain forecast for the weekend.

Integrity in bicycle blogging

To tell the truth, though, I bodged this repair the first time around. I took a look at the spokes adjacent to the broken one and came to the exact opposite conclusion than I should have about the spoke’s direction. I didn’t discover my mistake until I was giving this blog one final proof.

Bicycle hub with replacement spoke fitted -- backwards
Some mistake, surely …

I did the whole thing over, and this time I got it right (and took the picture that appears further up the page showing the correct orientation).

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