If you want to learn something, you have to be first and foremost willing to practice today almost forgotten activity - reading.
Scooter forks are designed for freestyle riding, not headless raving. Just like any human activity, riding a freestyle scooter requires the involvement of a gray cerebral cortex.
Freestyle scooter forks are durable but not indestructible. The forks are made of CrMo / steel or aluminium. The vast majority of threadless forks are made of aluminium. Aluminium forks are lighter than CrMo / steel forks.
Forks can be devided along the following criteria:
a) Material: Aluminum vs. CrMo (steel)
b) Threadless vs threaded
Threaded forks (they have a thread outside the tube) are only used in the entry-level completes for beginners. Threaded forks are almost exclusively made of steel and are two-piece (welded). Due to the thread they have a weakened tube wall and are therefore less rigid. Nor are they appropriate for the use with pegs.
c) One-piece vs two-piece forks
The vast majority of the forks in the after market are the so called one-piece forks. These are made out of one piece of aluminum using the technology of CNC or cold forging or molding. Therefore, they have no welds (strength factor). We can conclude that the vast majority of the forks in the after market are aluminium, threadless and one-piece forks.
The offset feature tells us whether the fork wheel axle is in the axis or outside the axis of the vertical tube. Forks can be divided into the Zero offset and Offset forks. Zero offset fork is more playful, offset fork is more comfortable.
e) Wheel diameter compatibility
There are several different wheel diameters in the market today. 100 mm, 110 mm, 115 mm, 120 mm and 125 mm. All the threadless and one-piece forks are compatible with 100 mm and 110 mm wheels. It's a standard. A large percentage of the forks can also accommodate 120 mm and 125 mm wheels. If you want to run 120 mm or 125 mm wheels on your scooter you´d better check your existing fork and also the deck (and brake).
The threaded, steel, two-piece forks used in entry-level scooters can mostly accommodate only 100 mm wheels.
f) Compatibility with compression systems
For the HIC / SCS forks, the length of the tube is important. For SCS forks, the fork tube should not stick out the headset more than 3 – 5 cm, depending on the SCS. See the following video https://www.youtube.com/watch?v=gFCUVUuY0fQ&index=8&list=PL625D416DF2978025
The HIC fork is similar in that. The tube of the fork must not stick out the headset more than is the length of the HIC shim (usually 4 - 5 cm). Thus, the tube of the HIC fork can be a bit longer than the tube of the SCS fork.
The tube of the ICS fork can be of any length. However, it should not be shorter than 4.5 cm due to the proper function of the clamp.
The regular ICS / HIC / SCS forks have the same outer diameter of the tube, i.e 28.7 mm.
The only exception to the rule is the IHC forks which have a smaller diameter (diameters vary by manufacturer), around 25 mm. To arrive at the 28,7 mm diameter the IHC forks use an IHC shim which has the same function as the HIC shim.
When running a fork in combination with the SCS it is necessary for the fork to have a thread on the inside of the tube. SCS-compatible forks have an integrated thread by default (from the factory).
For semi-compatible forks, it is necessary to install the starnut into the fork, see https://www.gizmania.es/freestyle-scooter-parts/kompresni-systemy/starnut-alu-fork.html or https://www.gizmania.es/freestyle-scooter-parts/kompresni-systemy/starnut-steel-fork.html
1 1/8 " starnut goes to the steel fork, 1“ starnut goes to the aluminium fork.
How to extend the lifespan of the forks
1) I behave fairly to my scooter
2) I do not throw it or bash it when angry
3) Land the tricks in a clean way. The more you soften the impact by bending in your knees the more you protect your fork from any unexpected damages
4) I use my compression system correctly see Kompresní systémy
5) Using the pegs protects your fork from excessive wear caused by grinding (this DOES NOT apply to steel forks)
6) Do not lend your scooter to your friends. They can easily weigh 30 kg more than you do and have a completely different style of riding
How to select the right fork
1) Aluminum or steel: If you are not a masochist, go after the aluminium fork. After all, the range of threadless steel forks is very limited.
2) SCS, HIC, IHC or ICS fork?
When selecting a new fork you need to consider your existing compression system. Generally, the HIC and SCS forks are mutually interchangeable. The ICS forks can be mostly used with the SCS / HIC compression systems (sometimes after minor modifications). The IHC forks are not recommended to be used with other compression systems.
3) Zero offset or offset fork?
Zero offset fork is more playful, offset fork is more comfortable. What does the crowd has to say? Over 95% of all the forks sold are ……….offset forks.
4) Beware of the headtube height. More on this in the following video