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Everything you need to know about the compression systems | Gizmania

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Everything you need to know about the compression systems

If you want to learn something, you have to be first and foremost willing to practice today almost forgotten activity - reading.

The purpose / function of the compression system is to hold the headset together. See the following video to learn more on this https://www.youtube.com/watch?v=Z4mGgBgPPa4

The compression system is very important, having a noticeable effect on the overall performance of the scooter.

Basically, the compression systems can be divided into the two broad groups, a) threaded compression systems and b) threadless compression systems.

The more detailed overview follows bellow:

a) Threaded fork + clamp = threaded system

b) ICS + clamp (threadless system)

How does the ICS look like? Long ICS https://www.gizmania.fr/freestyle-scooter-parts/kompresni-systemy/kubars-ics.html and a short ICS https://www.gizmania.fr/freestyle-scooter-parts/kompresni-systemy/ethic-ics.html

c) HIC + clamp (threadless system)

How does the HIC look like? See https://www.gizmania.fr/freestyle-scooter-parts/kompresni-systemy/hic-kubars.html

d) IHC or mini HIC + clamp (threadless system)

How does the IHC look like? See https://www.gizmania.fr/freestyle-scooter-parts/kompresni-systemy/district-ihc-compression.html It basically looks like the HIC but it has a smaller diameter. It can therefore be used with handlebars of a standard inner diameter (28.7 mm).

e) SCS (threadless system)

This is what the SCS looks like https://www.gizmania.fr/freestyle-scooter-parts/scs.html

Threaded fork + clamp + threaded headset

The oldest and most basic compression system of all. Used only in entry-level scooters for beginners.

There is no advantage to this system except for the low manufacturing costs. It is the only compression system using a threaded fork. All other systems use threadless forks.

ICS (Inverted Compression System) + clamp

A few years back the most common compression system mostly used on scooters for semi-advanced and advanced riders. The ICS was a norm back then. At present, it has been almost expelled by more efficient compression systems such as SCS, IHC or HIC.

The ICS is a bolt (long or short) with a steel starnut at the end of the bolt. The starnut goes to the inside of the handlebar.

The handlebar starnut comes either pre-installed from the factory (integrated / built-in starnut) or you need to buy one and hammer it down the handlebar downtube. The former is better of the two options. For more information on this watch the following video https://www.youtube.com/watch?v=Q0V7eL8eICM

The ICS works on the following principle: The steel starnut „bites" into the downtube on the inside and works as a fixation point into which the long bolt is screwed in. What you get is a fixed connection between the fork and handlebar.

However, there is *but* to everything in this world.

As mentioned countless times around the web the ICS does not work well with the CrMo / steel handlebars. The reason is obvious. Steel starnut vs. steel handlebar. Steel to steel does not work well. As a result, the starnut tends to slip on the inside of the handlebar at times, thus interfering with the *fork - handlebar* connection. What you end up with is a clearance.

The only exception to the rule is the proprietary Ethic ICS system which is 100% functional. However, it only works within the Ethic product family.

Therefore, the standard ICS can only be recommended for aluminium handlebars.

For proper functioning of the ICS, the handlebars must be slitted and have an outer diameter of 31.8 mm for CrMo handlebars and 34.9 mm for aluminium handlebars.

The length of the fork tube sticking out the headset must be longer than the slit on the handlebar. The length of the slit is 3.5 cm. The length of the fork tube sticking out the headset should be at least 4.5 cm so that the slit is sufficiently stiffened by the fork tube on the inside of the handlebar and the bar does not snap as a result.

The ICS will not work with the so-called HIC / oversized handlebars which are made of steel and have an inner diameter of 31.8 mm.

Major manufacturers of the complete scooters are no longer using the ICS. They use the HIC, IHC or SCS instead.

HIC (Hidden Internal Compression System) + clamp

You can ONLY use it in combination with handlebars that have an inner diameter of 31.8 mm and outer diameter of 34.9 mm.

If your handlebar does not match this specification you can not use the HIC compression system. How do I know which handlebars are compatible with the HIC compression system? This is either mentioned directly in the product name using descriptors such as HIC or Oversized or it is included in the product specifications.

How the HIC system looks like, how it works and how it can be installed is shown in the following video https://www.youtube.com/watch?v=b7ZrZlhu5S0

A clear-cut advantage over the ICS system is the stability of *the fork - handlebar* connection. It is a fixed connection with no tendency to get loose over time, no clearance.

Do you need to remove the handlebar from your scooter (commuting to school, public transport, etc.)? Easy. Just loosen the clamp bolts and remove the handlebar. Thats it.

The length of the fork tube must stick out the headset by at least 4 cm but must not be longer than the HIC itself.

Should you get bored with your HIC system over time, you can always switch to the SCS. You can either cut the slit off or insert a steel shim inside the handlebar. The steel shim / insert eliminates the function of the slit.

IHC (Inverted Hidden Compression) + clamp

IHC or mini HIC is the latest of a number of compression systems.

It is compatible with handlebars that:

a) are made of steel, have an outer diameter of 31.8 mm and inner diameter of 28,7 mm and are slitted

b) are made of aluminum, have an outer diameter of 34.9 mm and inner diameter of 28,7 and are slitted

The IHC differs from HIC on one important thing = it can be used with a standard sized handlebar with an inner diameter of 28,7 mm.

A clear-cut advantage over the ICS system is the stability of *the fork - handlebar* connection. It is a fixed connection with no tendency to get loose over time, no clearance.

Do you need to remove the handlebar from your scooter (commuting to school, public transport, etc.)? Easy. Just loosen the clamp bolts and remove the handlebar. Thats it.

The length of the fork tube must stick out the headset by at least 4 cm but must not be longer than the IHC itself.

The IHC is not recommended to be used with other compression systems (eg with SCS or ICS).

The IHC can only be used on forks with an outer diameter of cca 25 mm (referring to the tube).

SCS (Standard Compression System)

The best comes last. The SCS is, in our opinion, the most efficient compression system of all. It is a "2 in 1" system (compression + clamp). In addition, the SCS is the most headset friendly compression system.

One picture is worth a thousand words, see the following video

https://www.youtube.com/watch?v=gFCUVUuY0fQ

Which handlebars can be used in combination with the SCS compression system? Any handlebars BUT in case the handlebar is slitted you need to cut the slit off first or insert a steel shim inside the handlebar.

Handlebars used in combination with the SCS must not have a slit!! This is the basic rule that you need to bear in mind.

Most SCSs produced these days are compatible with both diameters i.e. with handlebars with an outer diameter of 31.8 mm and also with handlebars with an outer diameter of 34.9 mm. Before making a purchase, however, this fact needs to be verified.

The SCSs are almost always supplied with a steel shim. The shim is only used on handlebars with an outer diameter of 31.8 mm (= not on handlebars with an outer diameter of 34.9 mm).

For semi-compatible forks, the starnut needs to be installed into the fork before using the SCS.

Keep in mind:

1) Using the SCS positions your handlebar higher by about 4 cm.

2) This means that when you remove the slit (the length of which is usually 4 cm) and use the SCS, you do not lose any of the height of your handlebar

3) However, if you do not cut the slit off and use the steel insert / shim instead you add additional 40 mm to your bar height. A fact that many riders will appreciate!

4) Why is someone using HIC instead of SCS? Think *weight*. The HIC compression system ( + clamp) weighs less than the regular SCS.

However, the service life of the SCS is much longer than that of a clamp. Also, as mentioned above, the SCSs are headsets friendly.