Scooter Compression Systems

Scooter compression / Introduction

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A compression system connects the bar and fork so they turn together. It locks the fork into the deck headtube and keeps steering smooth. There are four main types used on stunt scooters:

• Threaded
• Inverted Compression System (ICS)
• Standard Compression System (SCS)
• Hidden Internal Compression (HIC)

Two variants are very common on complete scooters: IHC (Internal Hidden Compression / Integrated Headset Compression) — a lighter standard-bar system — and occasionally an ICS variant sometimes called ISC. Each system is described below.

Scooter compression / ICS (Inverted Compression System)

ICS uses an inverted compression bolt: the bolt runs up through the fork steerer tube and threads into a star nut pressed into the bar downtube (see the bar guide).

ICS is the simplest and cheapest system, but also the least durable. It needs frequent adjustment, the star nut is easy to damage, and you usually have to remove the front wheel to tighten the bolt. ICS only works with standard or aluminum bars that have a slit, plus a star nut and the right install tool.

Scooter compression / ICS recommended fork length

Deck, headset and fork must match for ICS to work properly.

Headtube length varies by brand, and the headset adds to the total stack height — so forks come with different steerer tube lengths. Some forks fit certain decks better than others with ICS.

We recommend a fork steerer tube that extends 3.8–5.1 cm above the headset. The upper limit is tied to the star nut sitting about 6.5 cm up inside the downtube.

Scooter compression / HIC (Hidden Internal Compression)

HIC is built for oversized bars with a slit.
A shim (shown in yellow in the image) with an outside diameter of about 32 mm slides over the fork steerer tube and is compressed down onto the headset with a compression bolt.

HIC is relatively affordable on its own, but oversized bars and clamps add cost and weight compared to ICS. It is stable and works well for tricks.

Scooter compression / HIC shim types

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HIC shims come in a few shapes, but they all do the same job: slide over the steerer tube, sit on the headset cap and give the compression bolt a solid surface to tighten against.

Scooter compression / HIC recommended fork length

As with ICS, deck headtube height and headset stack determine how much steerer tube you need.

We recommend a fork steerer tube that extends at least 4.5 cm above the headset. Some HIC shims are taller than 7.5 cm, which means a taller clamp and a very secure bar-to-fork connection. HIC is strong — a good choice for heavier riders who have had strength issues before.

Scooter compression / IHC (Internal Hidden Compression)

IHC works like HIC but is made for standard bars with a slit.
A shim with an outside diameter of about 28 mm sits on the fork steerer tube and is pushed down onto the headset with a compression bolt.
IHC is affordable and light — which is why it appears on most quality complete scooters. It is robust without adding much weight.

Scooter compression / SCS (Standard Compression System)

SCS was invented by Proto (patented). Many riders consider it the strongest system; others note trade-offs in weight and cost.

SCS combines the clamp and compression into one unit. The lower half of the SCS sits over the fork steerer tube; the bar downtube slides into the upper half (as shown).

The big advantage: no slit in the downtube, so you remove a common weak point in the bar.
Some SCS clamps only fit standard 32 mm bars. Others include a removable shim for oversized and aluminum bars at 35 mm.

Scooter compression / SCS clamp height

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SCS clamps come in two heights. Your choice depends on fork steerer length, headset stack and deck headtube.

The two sizes are 3" and 4" (3" clamps are often called “Baby SCS”).

Scooter compression / SCS recommended steerer tube length

Headtube height, headset and fork brand all affect how much steerer tube sticks up — so some fork/deck combos fit SCS better than others.

Recommended steerer tube length above the headset:
3" SCS: minimum 3.2 cm, maximum 3.5 cm
4" SCS: minimum 3.8 cm, maximum 4.8 cm