Our Guide to Buying: Headsets
What is a Bike Headset?
In a nutshell
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.
Headset Styles
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.
Threaded Headset
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.
Threadless Headset
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.
Head Tubes
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 work.
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.
