Cycling & Bike Bearings

What are cycling and bike bearings?

Bike bearings are the components that let the moving parts of a bicycle rotate smoothly with minimal friction. Although small, they are essential components found in the wheels, headset, and bottom bracket of a bike. They are also used in pedals, freehubs, jockey wheels, and the suspension pivots of full-suspension bikes.

Bicycles use two main bearing systems:

• Cup-and-cone (loose ball) bearings - loose steel balls, or balls held in a caged race, run between a cup and an adjustable cone. These are common on traditional hubs, threaded headsets, older bottom brackets, and many pedals. 
• Sealed cartridge bearings - self-contained units with their own inner and outer rings, balls, cage, and seals, pressed into the frame or component. These are now standard on most modern hubs, bottom brackets, headsets, and suspension pivots.

Most cartridge bearings used on bikes are deep groove ball bearings, typically in thin-section sizes. Headsets commonly use angular contact bearings, which are designed to carry the combined loads found in steering. Bike bearings are made in chrome steel, stainless steel, and hybrid ceramic versions with steel rings and ceramic balls. 

Why are bike bearings essential?

Bearings let wheels, cranks, pedals, and steering turn freely and efficiently, so more of the rider’s effort goes into moving the bike forward. They support the weight of the rider and bike, along with the forces from pedalling, braking, steering, and riding over rough ground. Smooth, correctly adjusted bearings make steering precise and stable and keep wheels running true and quiet. 

Worn, dry, or contaminated bearings can cause:

• Play in the wheels, cranks, or headset
• Grinding, creaking, or clicking noises
• Rough or notchy steering
• Extra drag, making the bike harder to ride
• Accelerated wear of hubs, frames, and other components

Over time, ball bearings wear and can begin to affect a bike’s performance, so replacing them is a routine and cost-effective part of bike maintenance. On full-suspension bikes, healthy pivot bearings are needed for the suspension to move smoothly and work as designed.

The main types of bike bearings

• Sealed cartridge deep groove ball bearings - these are the most widely used type on modern bikes, found in hubs, bottom brackets, pivots, freehubs, and jockey wheels. Seals help keep out dirt, water, and grit, which is important for bikes ridden in wet or muddy conditions. 
• Angular contact headset bearings - headset cartridge bearings have chamfered outer and inner edges that sit against matching angled seats in the frame and on the crown race. The chamfer angles must match the frame and crown race, as using the wrong angle can lead to poor fit, play, or damage.
• Double-row angular contact bearings
• Loose ball bearings - these are individual steel balls used in cup-and-cone hubs, threaded headsets, traditional bottom brackets, and pedals.
• Caged ball bearing races (ball retainers) - these hold a set of balls in a ring-shaped cage, making them quicker and easier to fit than loose balls. They are common in headsets and some hubs and bottom brackets. 
• Stainless steel bearings - stainless steel bearings offer durability and resistance to corrosion, which makes them a good choice for bikes ridden in wet weather, near the sea, or washed frequently. 
• Hybrid ceramic bearings - these have steel rings and ceramic balls, which are lighter and harder than steel balls. They are popular for performance road and race bikes.

How to choose the right bike bearings?

Identify the bearing - cartridge bearings are usually marked with a reference number on the seal or ring face. If the marking is worn away, measure the bore (inner diameter), outer diameter, and width in millimeters with callipers. 

Match the size exactly - bike bearings must fit precisely. Even a small difference in size can cause play, binding, or damage to the frame or hub. Choosing the right style and size can seem complicated, especially if you’re not sure what you need, so measure carefully and check the bike or component manufacturer’s specification.

Match the bearing type to the location - hubs, bottom brackets, and jockey wheels generally use deep groove cartridge bearings. Headsets generally use angular contact bearings with the correct chamfer angles, cup-and-cone hubs, and older components need loose balls or caged races of the correct size. 

Consider the riding conditions- rubber-sealed bearings are best for most riding, especially off-road and in wet weather. Stainless steel bearings suit wet, salty, or frequently washed bikes. Hybrid ceramic bearings suit riders looking for low weight and low friction, though they cost more.

Consider suspension pivots - pivots don’t rotate fully but rock back and forth under high loads. Bearings that contain more balls to spread the load are recommended for pivots but are unsuitable for hubs because the extra balls create more drag.

Replace in sets - replace bearings in pairs or complete sets where possible, such as both bearings in a hub. When replacing loose balls, replace them all with new balls of the same size.

FAQ - All you need to know about cycling and bike bearings

How do I know if my bike bearings need replacing?

Common signs include:

• Play or knocking when you rock the wheel, cranks, or handlebars
• Rough, gritty, or notchy rotation
• Grinding, creaking, or clicking noises
• Steering that sticks in one position
• A wheel that doesn’t spin freely when lifted

Why do headset bearings have different angles?

The angles describe the chamfers on the bearing, which must match the angled seats in the frame and on the crown race. 

Can I use standard industrial bearings in my bike?

Yes, if the size and type are correct. Many bike bearings are standard deep groove bearings. Headsets and suspension pivots are better served by bearings designed for those specific loads. 

How often should I check my bearings?

Check them regularly as part of routine bike maintenance, and more often if you ride in wet, muddy, or salty conditions. Catching wear early helps prevent damage to the frame, fork, and other components.