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Replacing the Headset
If you're going to replace a headset "by the book," you should have
a headset reaming and cutting tool, a headset press, and other weird stuff. In
other words, you need a bike shop. But what the heck... Life's an adventure. And
lots of bikers replace their headsets at home without disaster.
Good quality headsets have sealed bearings to keep out dirt. Replace your
grit-laden old headset with one of these babies, and you're set for life.
Headsets are sized to the fork's steerer tube: the standard fork with a
1-1/8 inch steerer needs a 1-1/8 inch headset. A 1-inch fork needs a 1-inch
headset.
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What's in a headset: The fork crown race sits on the
crown of the fork, holding the weight of the bike on the fork. The upper
and lower cups hold the bearings that let the fork turn easily. The top
cap and adjusting bolt determine how much the headset is compressed. |
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Banana Thunder has run through mud, snow, and rain for four
winters. The bearings have been cleaned and repacked twice, but are no
longer round. The headset rumbles when the fork is turned.
We're going to treat this old bike to a new sealed-bearing headset.
First step, remove the adjusting bolt and top cap with a hex wrench. |
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Now we loosen the bolts on the stem. The stem should easily
slide up and off the steering tube of the front fork. Be careful what you
do with the handlebars -- the cable housing could get bent and trap the
brake or shifter cables. |
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Now we drop the front fork out of the headset. In a
non-sealed headset, there's a row of bearings between the top of the fork
and the frame. Have a pan or clock under the fork to catch these bearings
as the fork drops away from the frame. If the fork won't go easily, place a piece of wood on top the
steering tube
and tap gently until it drops away. |
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Now remove the top cup. Lift the upper cover off the bearing
cup. Using a pipe wrench, twist the cup until it turns free and comes out
of the head tube of the bike.
(There aren't any threads. The bearing cup just sits in the tube, but
it will be tightly stuck.)
Take out the bottom bearing cup in the same way. |
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Now get the old fork crown race off your front fork. Put a
screwdriver on the underside, and gently tap the screwdriver with a hammer
as you move the screwdriver around the crown race. Once it's loose, slide
it off. |
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Install the new fork crown race from your headset. Slide it
down, curved shiny side up. To seat it tightly at the bottom of the
steerer tube against the fork's crown, use the old crown race as a
"pusher." Turn the old crown race upside down, and slide it down
against the new crown race. Tap down on the old crown race, moving around
from side to side, until the new crown race is seated. Then remove the old
race again. |
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This is where you really should have headset tools. But if
the receiving hole in the frames head tube is smooth and round, and the
fit of the new headset seems perfect, you can get by.
Apply a tad of grease to the first half-inch of the inside of the head
tube, top and bottom. Slide the headset's bearing cup into the head tube.
(Be sure you kept track of bottom versus top bearing cups.) Place a block
of wood over the cup, and use a mallet or 2x4 to gently tap it into
position. |
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Do the same thing for the bottom bearing cup. If you get
into trouble here, you can destroy the new headset, so be careful!
Here's a nice method for getting the bearing cups
into place: Get a large (such as 1/2 inch) threaded bolt, two nuts, and a
large fat washer (or two) that's big enough to cover the bearing cup. Put
one nut on the bolt, then the washer, then the second nut. Position the
bolt so the big washer sits on the bearing cup, and tap the head of the
bolt gently with your hammer until cup slides all the way into the head
tube.
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If you can't get the bearing cups into the headset, go to the bike
shop.
Lube the bearing cartridges with heavy grease. Also lube the
top surface of the fork crown race, and the treads of the headset
adjusting bolt.
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Install the bearings into the cups.
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Slide the fork's steerer tube into the new headset. Make
sure everything is seated properly.
Put the spacers (if any) back, and slide the stem onto the steerer. If
necessary, replace the star nut (located inside the fork's steerer tube).
If the headset has a different height than your old one, you may need to
add or remove a spacer. |
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Put the top cap on. Screw in the adjusting bolt -- not
tightly. Double-check the fit of the pieces. If it all works, tighten the
adjusting bolt until it just begins to compress the headset: no
up-and-down play, but no resistance to turning.
When the tension is right, tighten the stem back onto the steerer. Your
fork should now turn Like Buttah! |
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