A headset is a set of bearings that allows the steerer tube of your forks to rotate smoothly within the head tube of
your bicycle frame.
Headsets, particularly on mountain
bikes, can become less smooth as the bearings wear or if grit, mud or water enters the headset. A stiff, or
loose headset with ‘play’ in it, will impair your bike control as all your upper body movements are
transmitted through the headset to steer your bike.
If you need a new bicycle headset, then the massive number of different standards and styles can be confusing. Our guide will help you pick the right one for your bike.
What is a bike headset made of?
A headset is made of two large bearings, one top and one bottom of the head tube and then cups and spacers that allow them to sit inside the frame. The headset needs to match both the head tube of your bike and also the steerer tube of your fork so it is important to know the measurements of both of these.
What are the main bike steerer sizes?
As far as steerer standards or sizes go, there are three main ones. Straight 1-1/8th is simply a steerer tube with an unchanging diameter. It’s common on older and cheaper bikes. There’s now the more modern 1.5” taper, which moves from a standard 1-1/8” steerer tube where the stem clamps to a wider, 1.5” diameter at the fork crown. It’s much stiffer and also lighter. Finally, there’s full 1.5”, which uses an untapered steerer but is much less common except on a few specific models.
What are the main styles of bike headsets?
Headsets come in three main styles; conventional threaded, conventional threadless and integrated, some bike
manufacturers also have proprietary internal headsets. The threaded headset was once the most common of headset
designs so is found on many older bikes. Threadless headsets have no threads on the steering column; instead bearing
cups are pressed into the head tube. Internal headsets sit inside the frame itself.
On the threaded headset, there are external threads on the top of the fork steerer column and bearing cups that are
pressed into the frame. The standard sizes for threaded headsets are 1 -1/8” and 1-¼” Threaded
headset sizes are designated by the outer diameter of the steering column.
The bearings of threadless headsets sit inside bearing cups and can either use balls sat in a retaining cage, needing
regular maintenance or sealed cartridge bearings, which are fit and forget. Threadless Headsets must use a
compatible stem that matches the steerer diameter as the stem is used to apply pressure to the top race.
The stem binds to the outside of the column, and holds the top race in position. The threadless standards are 1-inch
and 1-1/8 inch diameter steering column. Threadless (otherwise known as press-fit) headsets can be either straight
1-1/8” or 1.5” taper, so it’s important to get the correct upper and lower bearings, this is
easily found by looking at the steerer.
On some designs, the headset bearings sit directly onto the frame or into non-removable pressed-in races. They can be
known as ‘internal’ headsets as they sit inside the frame, but are also commonly referred to as ‘Campy’
headsets. This name comes from the fact that Campagnolo
originally created them.
How do I measure a head tube?
Head tube standards are multiple, but by measuring the internal diameter of the head tube, it’s easy to tell
which your frame uses and buy accordingly. Make sure you measure both the top and the bottom width, as they are
different on tapered designs.
An interesting new standard is the 44mm external standard, which uses a straight 44mm internal diameter head tube.
This allows you to run straight 1.1/8” forks with internal cups, a tapered steerer fork with an internal upper
and external lower cup and a full 1.5” steerer with two external cups. Remember that while it’s possible
to run a 1.1/8” fork within a frame that has a tapered or 1.5” head tube with reducer races such as the
Norco Reducer Crown Race, the opposite won’t
Headsets that allow you to change the steerer angle (‘head angle’) of your bike are an exciting new
development, allowing you to tweak frame. They’re available to fit a wide variety of head tube and steerer
standards. The Cane Creek AngleSet
ZS44/ZS56 Headset Kit is a highly popular choice offering six offset angle adjustments so you can fine-tune your
bikes geometry, making the head angle steeper or slacker, depending on the terrain.