A bike fork is one of the biggest upgrades that you can make to your mountain bike. Not only does it absorb harsh impacts but it also allows the front wheel to track the ground more accurately and provides improved grip and stability as a result.
But before you start twiddling adjustment knobs there are a few things to consider before purchasing your new fork. Here’s our essential guide to help you choose the one that’s right for you.
Pick the one that will look best on my bike then?
No, sadly not. There are several factors that you need to take into consideration before choosing your perfect fork and the first is wheel size.
Mountain bikes are available with 26in, 27.5in (650B), and 29in wheels, and each requires a specific size of a fork. There are no complicated measurements or cryptic standards involved (in this bit, anyway), you just need to narrow your search to whichever wheel size your bike offers.
I know my wheel size, what’s next?
Axle standard. You will need to choose a fork with dropouts that match the type of axle used in your front wheel. Several different axle standards are available. Traditionally front hubs used a 9mm hollow axle with a 5mm quick-release (QR) skewer – also referred to as a QR axle. QR axles may still be found on lots of budget to mid-level bikes or commuters. However, for hard-hitting riders or gravity disciplines such as DH racing, Dirt Jumping, or Enduro, QR axles have largely been superseded by stiffer, stronger ‘bolt-through’ axles, also known as ‘thru axles’. These are commonly available in 15mm or 20mm diameter (bigger means stronger, but heavier), with the axle coming as part of the fork, rather than part of the wheel. A thru-axle will slide through one fork leg, through the hub, and then through the other fork leg, and is secured in place by a quick-release clamp.
Take your existing front wheel out and measure the current axle diameter to work out further narrow down what fork your bike can accommodate. It’s worth noting that some wheel manufacturers (like Hope, for example) offer after-market axle cups that can be swapped into their hubs to allow you to go up or down an axle size.
I know my axle diameter. Is that me ready, now?!
I’m afraid not. You’ll also need to work out your headtube diameter. The diameter of your frame’s head tube will determine the diameter you need on your forks’ steerer tube (the long metal bit that goes through the frame). The traditional standard has long been 1 1/8” but some modern bikes feature larger 1.5” head tubes or even tapered versions, where the diameter of the tube at the bottom (1.5”) is larger than at the top (1 1/8”), so you’ll need a fork with a tapered steerer tube to match.
It’s worth noting though that if you have a tapered head tube but want to run a straight steerer fork you can often buy a reducer cup for the larger lower part of the headset to make things fit.
You also need to work out what spring type you want to go for in the fork; air or coil.
Air or coil?! The age-old battle
Choosing between whether you want air or a coil-sprung suspension fork is one of the key decisions to be taken for would-be bounce purchasers. Put simply, air suspension works around using a chamber of compressed air as a spring whilst coil works around using, well, spring for a spring.
Whilst the former can be adjusted to suit riders of different weights by simply changing the air pressure with a fork pump, heavier or lighter riders may require coil springs to be swapped for units with a different spring rate (i.e. a stiffer spring for a heavier rider, and vice versa), which involves taking apart the fork. If you are opting for a coil-sprung fork (they’re often cheaper) then you need to ensure that the spring is correct for your weight. The air-sprung suspension has become de rigueur for most manufacturers now and offers easier adjustability, fewer moving parts, easier servicing, and lighter weight in exchange for a slightly higher price.
Do I just go for the most suspension travel possible, yeah?
No! That’s an easy trap to fall into and one which could spell disaster for your bike.
Fork travel (the maximum amount a fork can compress under load) varies considerably and according to the intended riding type. Things can range from short-travel 80mm forks designed for cross-country riding right up to big-hit ready 200mm forks aimed at the gravity addict.
It’s important to consult your manufacturer’s guidelines on how much travel your frame can handle before purchasing a new fork. All bike frames are designed with a set of geometry that works for their designed purpose. Increasing or decreasing suspension travel can dramatically alter the height of the front end of your bike and its head angle. Not only can this negatively affect the handling of your bike but it can also place unwanted strain on the head tube and, in the worst-case scenario, threaten frame integrity.
What does more money buy me?
Well, as with most things in cycling, more money often equals less weight. You can also get fancy low-friction stanchion coatings and lock-out levers to lock the fork’s travel in place. But more than that, when it comes to suspension, more money often equates to increased adjustability. In short, more knobs and clickers with which to dial in your preferred suspension characteristics.
Compression and rebound tend to be the minimum traits up for adjustment with more expensive forks offering things like both high and low-speed compression into the mix. Some forks also have the aforementioned travel adjust feature which lets you fine-tune their travel and ride heights too.
The more clickers and things the better then, right?
If you know what you’re doing, then yes but when it comes to setting up suspension it’s important to have a basic knowledge of what you’re adjusting and how it’s affecting your ride. Most quality manufacturers offer online guides or even smartphone apps to help get the most out of your setup.
For more info about bike forks, please check our official website: https://www.trifoxbike.com/