About the bike forks
Road Bike Forks
Full carbon road forks vs aluminum road forks
Full carbon road forks have a completely carbon construction, including the steerer tube. These tend to be the lightest, but most expensive road bike forks. Make sure if you are cutting the steerer tube yourself that you use a proper carbon cutting blade. There are forks out there which have carbon legs, but with an aluminum steerer, giving almost the same performance as a full carbon, with a little added weight and less cost.
If you are just looking for a cheap replacement fork, then there is no harm in looking at an aluminum fork. They might not be as light as a carbon fork but they will cost a lot less.
The size of road bike forks:
When buying a new road bike fork check that the steerer tube and brake mounts are compatible with your current set up. Most modern bikes will either need a tapered steerer tube (1.5” at the bottom, 1 1/8” at the top) or a straight 1 1/8” steerer tube. Older bike may require a 1” steerer, as found on the Raleigh 1” A-Head and Threaded forks.
Most road bike come with calliper brake, but disc are becoming more popular too, for which you will need a disc compatible fork.
Mountain Bike Forks
Coil Springs vs Air Springs
Forks offer their suspension travel via either an air spring or a coil spring. Coil Springs offer predictable and smooth performance but air springs have an advantage in that they can be adjusted to suit rider weight. How much a fork compresses under your weight – known as ‘sag’ – is very important as it allows the fork to extend into dips as well as absorb bumps. Being able to adjust this important to get maximum performance. Air springs also tend to be lighter, which means they are the most common choice for everything but extreme downhill use.
What is a damper on a bike?
The damper is a vital component in a fork, taking the energy from an impact and controlling how it is released. Many manufacturers offer forks that look externally similar but have different damper, with cost effective and more costly versions offering different levels of performance.
For example, The Fox 32 float is one such example and comes in either a cheaper ‘Evolution’ model or higher level ‘Factory’ spec. The difference is that the cheaper unit uses an ‘open bath’ damper where the damping oil can mix with air inside the fork, meaning that on rough descents the damping control becomes compromised. On the more expensive fork, a cartridge damper which isolates the oil from the air, is used to give consistent performance.
What are steerer tubes and what is the standard size?
Steerer tubes are the parts of the fork that inserts into the frame and is clamped by your stem. There are a number of different standards for steerer tubers. Many older frames use straighter 1.125” steerers, but in recent years tapered steerers, which go from 1.125” at the stem end to 1.5” at the lower end have become more common. These offer much greater stiffness and strength but aren’t compatible with older frames.