Replacing Spokes

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.

You must match the TYPE and the LENGTH of the spoke you're replacing.
You must match the TYPE and the LENGTH of the spoke you're replacing.
Get a replacement spoke of the same diameter as the broken one. Take the broken spoke to the bike 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. Another tip: Ordering a replacement spoke through the internet is really dicey, because you'll almost certainly order the wrong one.

Lubing the spoke nipple.
Lubing the spoke nipple.
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. Most mechanics recommend that you lube ALL the spoke nipples with light-weight oil or WD-40 and let it soak in while you work. That way, it's less likely you'll break another spoke while trying to true the wheel.

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 hole.)

The freewheel is removed by placing a section of chain across the top of the large cog, then standing on it. Or buy a professional "chain whip" to hold the cogs. Now use a freewheel tool specific to your bike's wheel, turning counterclockwise (in the direction the cogs would normally turn freely). After unlocking, lift the cogs off the axle.

Removing the freewheel from the wheel.
Removing the freewheel from the wheel.
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, its best to us...
Rotors are attached with 4 to 6 hex-head bolts. When reattaching, it's best to use Loctite on the bolt threads.
Check the rim and hub carefully for damage. Check the other spokes.
Check the rim and hub carefully for damage. Check the other spokes.
Check for any damage to the hole in the hub that could cut a new spoke. Sometimes a "spoke replacement" becomes a "rim replacement" or "whole new wheel."

Thread the new spoke through the hole. Make sure the head of the spoke is on the same side of the hub as before.

Guiding the spoke through the attachment points on the wheel.
Guiding the spoke through the attachment points on the wheel.
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.
Inserting the nipple through the rim and onto the spoke.
Inserting the nipple through the rim and onto the 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 and you're ready to put things back together.