This beginners guide to cartridge bearings is brought to you by 123bearing.co.uk
For a bike to roll smoothly it requires bearings. Modern sealed bearings not only minimise friction but also reduce the level of contamination that works its way through to the actual ball bearings inside them. Here’s an introduction to how that all works and why maintaining good bearings is a vital part of your regular maintenance routine.
An Introduction to the world of bearings
Take a look at your bike and the bearings may well be hidden but they are everywhere. From pedals, cranks, wheels, even your suspension pivots on your full suspension system contain bearings and they all need looking after. Wherever two or more parts move against or around each other you will find a bearing of one sort or another but for the bearing to function correctly you must maintain them well to avoid those really annoying creaking and clicking sounds while riding. In fact, if you start to actually hear your bearings then it’s definitely a sign you need to get to grips with them and give them a good dose of TLC.
Just like any other component on your bike, bearings require regular maintenance to serve you well for a long time. At 123Bearing, you can find any bearing you could wish for as well as advice on how to install and maintain them.
Focusing on wheels for a moment there are two main bearing types you could come across inside the hub – these are cartridge bearings and cup and cones bearings.
Bikes have used cup and cone bearing throughout history to keep things rolling and on older or some cheaper bikes you are still likely to come across these types. They essentially consist of lots of individual ball bearings sat inside a recessed ‘groove’. Essentially, if when you unscrew the covering bolts and rubber seals you can actually SEE the individual ball bearings then you can be sure you are dealing with cup and cone type. These are fiddly to maintain as there is a real risk you will lose the odd bearing when you service them and they are quite tricky to adjust to limit any side to side play in the wheel hub.
On the other hand, cartridge bearings are modern innovations. These are effectively metal rings that have the ball bearings neatly stored away inside them and out of sight. There is usually a plastic ring that sits over the actual bearings that not only keeps them all securely held in place but also acts as a seal to keep the worst of the grit and crud from the world outside. They have clear advantages over the old school cup and cone types and they require different servicing and repair processes.
Suitable Bearing to be used in Bike’s Wheel Hub
So we have established that the sealed cartridge bearing is the best type of bearing for the majority of bikes and as such they are pretty ubiquitous now on all modern bikes no matter the price point. Usually, a cartridge contains two rings, an outer and an inner ring, separated by a collection of closely packed metal balls. Despite the seal part they are not completely sealed against water and muck. Ultimately these seals are not effective enough to block water and dirt from reaching the bearings – it’s a compromise between protecting the insides and allowing enough movement of the cartridge against the bearings to move freely. So these seals can only reduce the level of contamination. It’s this balance of these two competing factors that often differentiates a good quality cartridge bearing from a poor one.
Reasons why cartridge bearings are the best option for bike wheel hubs
You may come across a type of bearing known as a bushing and it’s important to know the difference between this type of bearing and a cartridge bearing. Essentially bushings contain no actual bearings at all – they are just a smooth metal tube that separates two moving parts. Clearly friction is going to be a significant factor here and so they are generally not used in situations where two parts make complete or continuous rotations. So, you won’t see them in wheel hubs but you will probably come across them in pivot points of your suspension system. They have the advantage of being cheap, which is good as you will probably need to replace them more often than you would a cartridge bearing.
In some detail then here are four primary reasons why cartridge bearings are the best for bike wheel hubs.
Smooth rotation
With a sealed cartridge bearing, you will have a comfortable ride as it enhances smooth rotation. There’s unlikely to be any grit ingress around the bearings that will result in nasty vibrations or ‘stiction’ while you ride. Additionally, these bearings promote a balanced power transfer. They are made from high-quality materials, which reduce friction rates.
Easy to maintain
Cartridge bearings are maintenance-friendly, making it easy for you to repair them. You don’t need to follow complicated procedures or specialised tools to replace them. You can generally maintain them yourself with a bit of cleaning and occasional greasing. One word of warning! Don’t clean them with a jetwash. Inside those seals the bearings are packed with grease and although the seals will keep out most of the water, a jetwash can sometimes penetrate the seal and blast out the grease. Once it’s out, it’s pretty hard to put it back without damaging the seals.
Availability
As stated earlier, these cartridges are almost ubiquitous now so availability of replacements is good. They come in standard sizes and so compatibility is not really a problem even for the home mechanic.
Durability
Cartridge bearings are specially designed to withstand any demanding requirements of riding. They can handle axial and radial loads, including the forces from the braking, pedalling and punishment they take from riding offroad. Essentially if you look after them they will last for a long time.
