Bicycle forks attach your front wheel to the main frame of your bike - via a steering tube that sits in the headset of the bike frame. Forks are found on every single type of bike, mountain bikes, road bikes, gravel bikes, kids bikes and hybrid bikes all use bike forks - but that’s where the similarities end. Bike manufacturers spend a lot of time choosing and specifying the right forks for the bikes that they produce, with many choosing to buy forks in from specialist suspension companies, such as Fox rather than create design and develop their own.
Mountain Bike Forks
Mountain Bike Forks are the most complex type of bike fork that you can buy - mainly because most MTB forks use suspension, which moves up and down to absorb harsh impacts, whilst improving grip and handling on rough terrain.
There are a number of considerations to make, when purchasing a bike fork for your mountain bike - the first of all being the fit of the mountain bike fork itself. There are different wheel sizes in use on different mountain bikes, with 26 inch, 27.5 inch (also known as 650b) and 29 inch wheels being used - which all need a different size fork to be compatible.
Mountain Bike Forks also need to match the type of axle that your bike uses. Mountain bikes have historically used a QR axle - which has a 9mm hollow axle and a 5mm quick release skewer. Those riding more specialised mountain bikes, such as downhill mountain bikes - will likely have a bolt through axle, which have become known as ‘thru axles’ in the industry. These thru axles are available in 15mm or 20mm diameters - and are secured by a quick release clamp. To find out the axle size required, take your front wheel off and measure axle diameter - some suspension fork companies offer axle cups that allow some flexibility in axle size.
The next consideration is head tube diameter - the fork needs to fit into the frame in order to work. There are a couple of options available, with the most common two being 1 ⅛" and 1.5" diameter.
With sizing largely covered off, you also need to choose between the two technologies that allow the suspension fork to move. Air coil suspension forks are available alongside coil suspension forks. Air forks use a chamber of compressed air to provide damping, whilst spring loaded forks use a spring for the same effect. The advantage of air forks is that they can be adjusted easily on the move, where a coil sprung fork may need the coil changing and swapping out.
The second performance based choice to make is the amount of travel required from the suspension fork. Whilst it’s incredibly tempting to choose the biggest fork, with the biggest amount of travel - you may suffer on the trails. Those riding cross country, only need around 100mm of travel for the fork to be effective, whilst those doing downhill mountain biking need a fork which can travel up to 200mm. Your bike frame will have recommendations here, as to how much travel the frame is designed to accommodate, ignoring this advice can leave a bike frame unbalanced - and difficult to handle.
Mountain Bike Travel Guide
How to change a Mountain Bike Fork
Road Bike Forks
Although Road Bike Forks are rigid - so do not have any moving parts, that does not make them any less important. Many cyclists choose to upgrade their road bike forks, in order to improve performance and handling on the road, whilst also shaving a few grams off the weight of the bike itself.
The biggest difference between a lot of road bike forks on existing bikes, is that they are made from aluminium - and in older bikes, they may even be made from heavier steel. It’s difficult to find any aftermarket forks which are not made from carbon fibre. The benefits of upgrading to carbon fibre forks are well known, as well as weight saving - carbon fibre forks also absorb shock, meaning that your road bike provides a more comfortable ride, especially over longer distances.
Whilst many people buy road bike forks when they have some spare money, and want to upgrade their bike - many cyclists are forced to upgrade them after a crash or impact.
How to choose Road Bike Forks
Choosing road bike forks is not as complicated as choosing a mountain bike fork, but there are some things to look out for. Lighter, more aggressive shaped forks will not be as comfortable as more relaxed forks. Whilst more expensive forks are fully carbon fibre, mid-range forks will use both aluminium and carbon fibre.
Forks designed for endurance bikes/sportive road bikes will also have a more relaxed geometry - for more comfortable riding performance.
Road Bike Fork Fit
Your new road bike forks will need to have the same head tube diameter - so you will need to pick a road bike fork with the same size steerer tube. Modern bikes typically use a 1 ⅛ steerer tube.
Road Bike Forks & Handling
Different road bike forks will make your bike handle different - even just slightly. This is caused by the angle forward of the fork itself, less angle will make for more involved handling - with more angle meaning a longer wheelbase, which is more stable and easier to turn. Those looking for the most aggressive road bike fork, should choose straight blade forks.
Road Bike Fork Considerations
Ensure that new road bike forks can accommodate disc brakes if you have them, with disc brake mounts - as these cannot be retrofitted. Similarly, ensure that your forks can also accommodate larger tyres - such as 28mm diameter road tyres.