A broken or overstretched spoke makes the rim lose support. This makes the
bike unstable in a tight turn. The extra stress on nearby spokes may make them
break. Replace a damaged spoke as soon as you can. Replacing ALL your spokes (lacing
the wheel) isn't a job we recommend for the home mechanic.
To compensate for a broken spoke while on the trail, you can do some on-trail
truing. Tightening the same-side spoke on each side of the broken spoke may
straighten the rim, reducing wheel-wobble and allowing you to brake effectively
on the way home. See the section on wheel truing.
||Get a replacement spoke of the same diameter as the broken
one. Take the broken spoke to the shop with you, so you get the right
length and diameter. Most mountain bike spokes are 15-gauge. If the spoke
gets fatter as it nears the hub, it's "butted." if it also
flares as it approaches the rim, it's "double-butted."
It's often best to replace the nipple along with the spoke.
||Remove the damaged spoke. You may need to remove another
spoke to clear the head. (Depending on your lacing pattern, another
spoke's shaft may overlie the head of the broken spoke.)
You'll need to do some truing after replacing the spoke. Lube the spoke
nipples with light-weight oil or WD-40 and let it soak in while you work.
|If the spoke is on the rear tire, you'll need to remove the
cogs. (If the spoke is on the freewheel side, you won't be able to get it
into the hole. If it's on the other side, you'll have to bend -- and
damage -- the spoke to get it past the large cog as you thread it through
The freewheel is removed by placing a
section of chain across the top of the large cog, then standing on it. Use
a freewheel tool specific to your bike, turning counterclockwise (in the
direction the cogs would normally turn freely). After unlocking, lift the
cogs off the axle.
If you have disc brakes, you'll need to remove the rotor.
Note the direction of the arms that support the disc (or put a crayon mark
on the top side) so you put the rotor back the same way.
Rotors are attached with 4 to 6
hex-head bolts. When reattaching, it's best to use Loctite on the bolt
||Check for any damage to the hole in the hub that could cut a
Thread the new spoke through the hole. Make sure the head of the spoke
is on the same side of the hub as before.
||Slide the spoke up to the hole in the rim, following the
"lacing pattern" of the other spokes. For example, if you have
"3-cross" lacing, you put the spoke past two spoke shafts, then
move it over to the opposite side of the third spoke.
||Thread the nipple onto the spoke. Tighten it to about the
average tightness of the nearby spokes.
Squeeze the spoke shaft towards nearby spokes from each side by
gripping two, then three, then four spokes at once. Recheck the tightness.
Now true the wheel.
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