Compression system

The compression system reduces the unwanted "wobble" of the headset. These are the two most important parts of the "compressed" scooter, therefore attached to each other. The compression system must always be tightened, otherwise it could deform the headset and affect the leverage, causing the fork or handlebar to break.


Many standards have been developed over the years and you can now choose between 4 systems, ICS, SCS, HIC and IHC. It can be very difficult to know which compression system is suitable for each fork or headset. For this reason we have created a list on our BLOG that covers most combinations and shows what is suitable for what. For each item in our shop we have a button "find out if the desired part is compatible", from there it goes directly to our BLOG to this list of combinations. Of course, we can't create all the combinations, so if it doesn't exist, just ask us by e-mail and we will answer the question

Although there are aesthetic differences between the 4 systems, they all have the same objective. It presses the fork against the headset end caps by combining headset compression to keep the ball bearings under constant pressure and to strengthen the front end assembly.

When you first attach and tighten the headset, it is normal for the compression system to continue to detach. Therefore, you should always follow the system you chose in the beginning: it takes just a little time to harmonize the components. It is also a good idea to use a thread locking varnish that prevents the thread from coming loose due to vibrations when screwing the scooter in.

If problems of this type persist, poor assembly may be the cause. Disassemble the individual components to locate the problem and look for solutions. Of course you can always contact us if you need help, but remember that we always need a lot of information about the problem as we cannot see the scooter and have to solve the problem remotely.


ICS (Inversed Compression System)

1: size 31,8

2: starnut

3: compression bolt

4: fork

5: clamp


The ICS was adapted in 2006 by Andrew Broussard (Proto) and perfected for the scooter sector.

The concept is very simple. A star nut with internal thread is anchored in the handlebar and screwed with an M6 screw (the length of the screw varies) from below through the fork directly into the internal star thread. This will bring the bar to the fork and compress the system. The advantage of this system is that the bar is in direct contact with the fork, so you don't have to screw too hard. Manufacturers nowadays use M6 Allen head screws. If you have a short screw (e.g. for District or Ethics ICS brands) you will need a long hexagonal wrench (~ 20cm) to screw the screw through the fork into the star nut. The screw is inserted into the hole between the fork arms through the hole at the end of the fork tube and screwed with the star nut into the handlebar.

If you have purchased a so-called long ICS, a normal Allen key is sufficient, as the bolt is only inserted into the recess of the hole between the fork arms.

The main disadvantage of the ICS is that you have to remove the wheel each time to retighten it. The other problem is that you can only remove the handlebars if the system is completely unscrewed. Even if only few components are used, you are very dependent on the fact that the nut does not loosen or the thread is not faulty.

High-end handlebars often undergo heat treatment, so they are very dense and the star nuts cannot grip the metal as well. Therefore, due to the softness of the material, ALU bars are more suitable for star operation, but it is still common to use it in both types of metal.

For some handlebars such as District and Ethic DTC. There is already a star nut pre-installed in the handlebar, which is an advantage if you have never attached a star to the handlebar, which can sometimes be a bit difficult. We also offer a cheap tool in the Starnut shop, which of course makes it easier to fix the star correctly and straight.

In 2011, Addict introduced the "ICS10", which is also used today by Ethic DTC. Instead of an M6 thread, an M10 thread is used, i.e. a much thicker and therefore more stable screw, so the system can be compressed much better, however, this system is only intended for the mentioned brands.

If you do not have the Starnut installation kit mentioned, you need a simple hammer and a piece of pipe or a peg, even a pawl is used to drill the star.

First, place the star nut on the handlebar tube. For hammering, we recommend a tube whose diameter must of course be smaller than that of the bar, which applies an equal force to the star nut and prevents the star nut from rotating obliquely.

The nut must not be pushed too deeply. The screw must always be inserted into the nut in order to realise the maximum extent to which the star nut can be inserted into the handlebar. Otherwise the bolt will certainly be too short and compression will not be possible.

Otherwise the star nut cannot be too close to the beginning of the handlebar, otherwise the fork will touch the star nut and not fit properly. The most common ones are ab

Before tightening the compression, it is important that the clamp is loosened! If you do not loosen it, it will prevent the compression parts from contracting.


SCS (Standard Compression System)

1 : bar

2 : compression bolt

3 : shim

4 : SCS

5 : compression thread

6 : fork


Also invented by Proto boss Andrew Broussard around 2008, this system is clearly the best, very simple with a lot of possibilities.

The SCS is a combination of nut and compression. The SCS is internally milled to give two different inner diameters. The upper part holds the handlebar and the lower part holds the fork. Between the components is a washer, which rests on the inner shoulder of the two different diameters. In addition, there is an M6 screw that is screwed from above through the SCS hole in the fork, either it will use a fork that already has a matching thread or an insert, or you will screw in the appropriate fork with a star nut.

When using the SCS, it is recommended to use a handlebar dedicated to the SCS, which does not have a clamping slot and can therefore be used over its entire length, because if your handlebar has a clamping slot, you must first saw the handlebar off half of the slot before you can use the SCS.

If you have a handlebar with a slot and you saw it, you do not lose the entire length of the section, because the SCS compensates again for part of its height. In the end you lose about 1 to 2 cm of bar height, you have to calculate this in advance. Because just when you start to get used to the height of the handlebars, suddenly you find yourself one or two centimetres shorter, there may be a new adaptation time and in some tricks this is not welcome.

The big advantage of the SCS system is that it is very efficient, easy to install and compatible with many standards and oversized bars.


Since a SCS is usually quite large and therefore a little heavier, it can affect the aesthetics and weight of the scooter, but there are now smaller and lighter SCS systems available, such as the Tilt in LT version or the Phoenix and Proto the baby. It is important to note that only standard SCS bars are compatible.


Furthermore, in some cases it is necessary to work with headset spacers or to shorten / cut the fork length, especially if the fork tube is too long or the head tube too short. Unfortunately the question of whether and how much to cut cannot be answered, as there are manufacturing tolerances and it would be wrong to set a length, as this would lead to forks that are too short.

The SCS system is not bolted to the handlebar like the ICS, but with an SCS clamp, so you have to remove the handlebar to loosen or tighten the system. Remember, you have to remove the whole wheel with the ICS, so the SCS is certainly the most suitable solution.

If you have decided to cut your slotted handlebar for riding with SCS and want to use another system such as ICS or HIC later, you must cut a new slot in the handlebar. When you return to ICS or HIC, you must take into account that the bar is shorter than before, because the height of the SCS is missing.


HIC (Intern Compression System)

1: Bar

2: Compression bolt

3: Puck

4: Shim

5: Starnut

6: Fork


Invented by the Mosbrucker brothers of in 2007 and since then no longer indispensable for our sport, the most important thing to know about this system is that it requires a HIC handlebar. This is a handlebar with a larger inner diameter than standard or SCS bars and a slot for the clamp. Very often these HIC bars are also called "Oversized handlebars", but they should not be confused with oversized ALU handlebars which only have the larger outer diameter but the same inner diameter is not suitable for the HIC system.

In addition, this system requires a spacer inserted on the fork tube. The spacer is then fixed from above with a top washer using a screw that is screwed into the star nut. When the system is securely in place, push the bar onto the spacer with (at least) double tightening.

The HIC system is light, but unfortunately HIC bars are even heavier due to their larger pipe diameter, which far exceeds the weight savings of the system.

As with the SCS, the system can only be tightened or loosened after the handlebars have been removed.

It is advantageous that you acquire a strong HIC clamp like the complete HIC systems offered by VertX or APEX, which are high quality systems with a high quality clamp in the kit. As mentioned above, you absolutely need a HIC OS handlebar, this handlebar is not usable on any other system unless you remove the shim and ride with an SCS. HIC handlebars are much more common in the USA than in Europe, but European riders are discovering this system which is becoming more and more widespread, especially because HIC-OS handlebars are very stable.


IHC (Intern Hidden Compression System)

This system was invented by Envy, formerly Blunt, in 2011. It is a variant of the HIC that uses a fork with a narrower outer diameter. Therefore, there is room for a shim on the fork and you can use a standard size bar despite the shims.

The advantage of this system is that no oversized HIC handlebars are needed, and it can be steered with the more common standard or ALU handlebars. The fork is also slightly lighter due to its smaller diameter. The system combines the advantages of the HIC with the possibility of riding many handlebars.

The disadvantage is that the ICS, SCS and HIC compression systems have been adopted by many brands of scooters and only Envy / Blunt and Chamfer are currently the only manufacturers using IHC systems. Since the IHC fork is narrower than non IHC forks, you need a smaller diameter compression washer, but this is included with the corresponding IHC fork.

Here you will find all our compression systems for your new freestyle scooter.

Stunt Scooter Lexicon