Bicycle Repair

Replacing broken rear wheel spokes
Published on May 21, 2022.

Driving back home from work on Thursday I suddenly heard a strange noise and felt a wobbly sensation on my bike. Taking a closer look, it turns out two spokes in the rear wheel have broken.

Bike before the repair
Broken spokes

Over at the Toolbox Markdorf we have a bike repair stand and a wheel centering stand, as well as other bike-related tools. So I drove over there to do the repairs.

Rim in centering stand
Empty holes of broken spokes

On the gear shift side, a small plastic disc prevents the spokes being taken out. It can simply be pulled off and put back on afterwards.

Plastic disc on gearbox

Removing the brake disc requires a special tool by Shimano, called the "Lock Ring Tool TL-LR10". Fortunately I already bought that when I rebuilt my wheel.

Shimano Lock Ring Tool
Opening Lock Ring with a Wrench
The removed brake disc
Hub without brake disc

Here you can see the two broken spokes, next to six unused ones I still had left over, because my rim only needs 32 spokes.

Two broken spokes next to new ones

Normally I would have centered and tensioned the rim and spokes myself, but unfortunately Philipp borrowed the Spoke Tension Meter from the Toolbox Bike Workshop, and I was not able to reach him on short notice 😉

But then I remembered that I saw a small local bike workshop in Markdorf, Fahrrad Hienerwadel. So I quickly went over there and brought my prepared rim, only needing to center and tension the rims. The shop owner was able to do the job quickly on-the-spot, in less than 20min with 15€ having been exchanged, I was on my way back to the Toolbox.

He did a good job centering the wheel. I put the tube and tire back on and pumped it up, using an old emergency compressor from a Mercedes I salvaged, fed by a 3S Quadcopter LiPo.

Checking the fixed rim
Pumping up the tire
Finished wheel

Back home, I just had to put the wheel back in the bike frame. Now it's good to go again!

Bike without back wheel
Bike after the repair
Bike after the repair

As I mentioned above, I already completely re-built my rear wheel with new spokes a while ago, in September 2020. The tools for this were ordered by the Toolbox and are now available there, namely: repair stand, centering stand, tension meter and spoke wrench.

Here are the verbatim notes I made back there, with some specs of my bike and wheel, as well as some useful links if you want to rebuild your wheel as well.

Centurion e-Fire 408 Tour (??)

Shimano Alfine SG-S7000- 8

Muttern: Rechts Blau, Links Gruen

Felge Laufrad:
Alexrims MPD-14, 36 L. (??)
28″ / 622
ETRTO 40-622

32 Speichen, 3-fach gekreuzt

Original Speichen: 1.2mm Durchmesser
Ersatz Speichen von Werkstatt: 2mm Durchmesser

Passende Spannung fuer Stahlspeichen mit Toolbox Messgeraet:
ca. 22 bis 24 (oder 21 bis 25)

Durchmesser des Kreises durch die Speichenenden D = 600 mm
Durchmesser des Nabenflansch-Lochkreises d = 92.6 mm
Abstand Flansch - Mittelebene a = 28.65 mm
Anzahl Speichenkreuzungen k = 3
Speichen-Anzahl n = 32
Speichenlänge = 286.0 mm

286mm ist die korrekte Laenge!

Even though I heard bad things I have to say rebuilding a wheel is not that hard. Just read through some tutorials on the web or watch some YouTube videos on the topic and try it yourself!

Also take a look at part 2 of this repair!