On the face of things, a headset is ‘just’ a pair of bearings and some things that screw together but to think that is to really undervalue an essential part of your bike.
Here’s our essential guide to everything you need to know about headsets, how to look after them and what to look for in your next one.
Headsets at a glance:
- The headset consists of a large set of bearings allowing your fork steerer to rotate inside the frame’s head tube
- Every movement you make with your upper body is transmitted into the bike through the headset
- Most modern bikes feature a threadless headset which can be integrated, internal, and external
If you don’t want to read our best bike headsets buying guide, you can go directly to the relevant product via the links below:
If your headset isn’t working to its optimum then you’ll know immediately and spend every ride thereafter cursing its rattles and creaks. Reverberative irritations aside, a knackered headset can damage your frame and needs to be taken seriously.
So a headset’s just a set of bearings then, that’s it really?
Well, yes and no. In simple terms, your headset is just a large set of bearings which allows your fork steerer to rotate inside the frame’s head tube and control what direction your headed in. But a well-fitted, smoothly functioning headset is essential in order to make the most of your bike’s handling and to keep you headed where you want to go.
Parts-wise it consists of two large bearings (one for each end of the head tube) and a collection of cups and spacers which allow them to sit inside the frame.
And why do they matter?
They matter a lot. Every time you turn your handlebars, you’re relying on the headset to convert your input into a smooth change of direction. Pretty much every movement you make with your upper body is transmitted into the bike through the headset.
Mountain biking is the smoothly-operating bearing’s natural enemy. Mile after mile of coping with being shot-blasted by mud and grit is summarily rewarded with repeated washing with oil-stripping bike sprays and cleaners.
Likewise, despite using beefier, larger diametre headsets, mountain biking involves a lot of forces being transmitted through the front of the bike. These can range from landing a massive drop on a DH racetrack to the constant reverberations of the roots section on your favourite local singletrack, whatever it is, your headset has to deal with it.
OK, so there’s a bit more to it then. But how do I know if mine is due for replacement?
Trust us, when your headset is at the end of it’s tether, you’ll know! If the bearing cups aren’t fitted properly then it can suffer from the dreaded ‘play’ effect. This rocking of the cups backwards and forwards not only feels horrible on the bike but it risks damaging your frame too. Likewise, if your steering feels notchy or somehow indexed then your headset’s bearings are more than likely knackered and are due for replacement.
Just like the other large set of bearings which keep your cranks spinning smoothly (the bottom bracket), making sure that your headset is fitted and performing correctly is essential. When installed and working correctly, your headset is one of the real unsung heroes of your bike as it allows you to make every steering input precisely whilst also really being able to feel, through the fork, what the road or trail is doing underneath you.
Right. I’ll get a new one. Do I just tonk it out with a hammer then?
No! Put the hammer down! Planet Headset is a complex place and it’s important that you understand what you’re looking for and exactly what fitment and style you need first.
Now, if you’re an urbane hipster type with a vintage road bike or fixie leant up in the garage then it’s more than likely that you’ll have what’s called a threaded headset. It’s recognisable by its two large nuts between the stem and the top of the head tube and is usually found on older bikes.
Threaded headsets feature an adjustable bearing race screwed onto the fork itself and secured by a locknut, meaning two special spanners are required to adjust the bearings.
Most modern bikes now feature what’s known as the threadless headset.
Rather than screwing together, a threadless headset relies on two cups with a pair of bearings inside each being pressed into each end of the head tube. The gloriously named star-fangled nut (SFN) is then inserted into the steerer of the fork. A small gap is left between the top of the forks steerer and the top of the stem so that once the top cap is tightened into place, the stem compresses everything together nice and snuggly.
However, the bike industry is forever swamped with new standards and ways of doing things so there are now several different types of threadless headsets now available.The most important ones to know about are integrated, internal, and external.
Wow. There is a bit more to it then? I’m confident it’s a threadless I need but what are those last three options about?!
OK,this is basically a reference as to where the headset’s bearings reside; whether within the frame itself, in cups inside the frame or in cups outside of the frame. Integrated means that you can just drop the bearings themselves into your frame’s specially-machined head tube with no need to press in cups or anything like that. It’s a tidy solution that cuts down on hardware and makes servicing a doddle. Internal means that the bearings still sit inside the head tube but within low profile cups.
Finally, external means that the headset relies on cups which sit proud of the head tube.
There is no real one preferred headset design, in terms of the three listed above. Each performs well and whichever your bike uses will be based upon its designers choices when balancing materials and stresses during the design process.
Gotcha. Now, the bearings are all the same, are they?
No. Of course they’re not! In short, you get what you pay for. Cheaper headsets get cheaper bearings, the decision is whether you want to replace them in a year or just about never. Ball bearings are the most common type of bearing used but you’ll also find cartridge and needle varieties used. Cartridge means that each set of bearings are housed in a single sealed assembly, they are generally better sealed and last longer. Needle bearings replace the balls with a ring of small rods. Ceramic bearings are available too featuring, you guessed it, ceramic balls which offer a smoother feel and longer life but you’ll have to pay for these gains.
So if I’ve got this right and finally tracked down the headset that’s right for my bike, is fitting it straight forward?
When it comes to headset installation there are tools available for the experienced home spanner slinger which can make things a fairly straight forward doddle. Take your time, think the process through and it’s a fairly painless half hour or so of work. The key is to have it straight in your head what order everything is going into place in and use a high quality grease so that you can get it all out again next time.
Because headsets are made of multiple parts, you can often prolong the life of your unit by replacing worn-out items such as bearings individually, without having to fork out for a new headset.
Keep your headset turning smoothly through all conditions with our selection of parts including upper and lower bearings, bearing races, seals, compression rings, top caps, star-fangled nuts, headset bolts, reducers and more.
BMX headsets are largely similar to MTB/road designs but can also suffer/benefit from a myriad of options. Most modern bikes and after market frames now feature integrated headsets which helps lower stack height and provide a cleaner look. Many older frames feature external headsets which require the cups to be pressed into the frame.
How to service a bike headset
Staying on top of headset maintenance can help to dramatically prolong it’s life.
- With your bike in a stand, remove the front wheel.
- Loosen your stem bolts and remove your top cap. Keep a hand on the fork at this stage otherwise it can drop through.
- A thin flat-headed screwdriver is ideal for gently prizing the various spacers and caps apart. Place them on work bench in the order you remove them. Inspect for any damage and clean thoroughly.
- Pop the bearings out and clean. Feel for any notchyness before cleaning/greasing the cups and reassembling. Check manufacturer’s website for recommended torque settings.
What size is my steerer?
What headset you go for will be dictated by what size your fork’s steerer and your frame’s head tubes are. There are three sizes of steerer and one hybrid of two of them:
- 1”: Typically, the older-style threaded headsets will be found on bikes with a 1” threaded fork steerer (although 1” threadless headsets are available from some manufacturers).
- 1 1/8”: The standard fork steerer diameter for most road and MTB bikes is 1 1/8”.
- 1.5”: Some modern gravity bikes or speciality road bikes use 1.5” fork steerers and correspondingly larger head tubes for extra strength and front-end stiffness.
- Tapered: This is a hybrid of the 1 1/8” and 1.5” systems and is found on a lot of modern road and mountain bikes. The lower race is the larger size to bolster stiffness and strength whilst the top race is the smaller one to save weight. It also enables clever frame designers to use larger-diameter down tubes which help to promote stiffness in the bottom bracket area. Tapered head tubes are designed to be used with forks that have tapered steerer tubes but you can get reducers to enable ‘standard’ 1 1/8” steerers to be used in frames with tapered head tubes.
Speak fluent headset in just a few simple terms
- External This is the traditional type of threadless Aheadset which has upper and lower bearing races pressed into the frame, with the bearings positioned outside of the head tube. These can typically be found on bikes with 1 1/8” head tubes.
- Headset A large pair of bearings which allow your bikes fork steerer to turn inside the head tube of your frame.
- Integrated A type of headset used on frames where the head tube is machined so that the top and bottom bearings can fit directly inside the frame, eliminating the need for extra bearing cups and enabling the bearings to sit flush with the frame for an attractive, clean look. Because they have less parts, they are a little lighter than other headset options. They are often used on road and MTB racing bikes and are especially common on bikes with tapered head tubes, as the lack of a lower external bearing race means more surface area for the down tube joint and a neater, more aerodynamic interface between fork crown and head tube. They also help to lower what is referred to as stack height meaning that the handlebar height isn’t altered by chunky headset cups.
- Internal A type of headset for bikes without machined head tubes and require aluminum cups to be pressed into the top and bottom of the tube so that the bearings can sit into them. It can sometimes be hard to distinguish whether your bike is using an integrated or internal headset without taking it apart!
- Seals No, not the fish-gobbling variety rather the type that keep grit and mud out of your bearings for as long as possible. A high-end headset is a significant investment but is one that should pay off in the long run, keeping your bike running smoothly through years of all-conditions riding. Quality seals are a big part of that.
- Tapered Refers to a fork steerer or head tube which features a lower race of 1.5” and an upper race of 1 1/8”. A ‘straight’ 1 1/8” steerer can be made to fit inside a tapered head tube with the help of a reducer plate.
- Threaded The older type of headset, recognisable by its two large nuts between the stem and the top of the head tube. It fits forks with threaded steerer tubes, typically of 1” diameter. These are increasingly rare and are now generally only found on older bikes.
- Threadless/Aheadset A more modern headset design where-by the bearings are tensioned via tightening a top cap which compresses the component parts together.
- Top cap The alloy cap which compresses the stem down on to the headset, secured in place by the star fangled nut inside the fork’s steerer.