This guide is written by the team at ProScooter.Shop — Georgia's dedicated freestyle scooter store in Tbilisi.
What Is a Compression System?
A compression system is the mechanism that connects the bars to the fork and holds the entire front end of a freestyle scooter together under tension.
To understand why it matters, picture the anatomy of the front end: the fork slides up through the headtube of the deck via the headset bearings, and the bars slot into or onto the top of the fork steerer tube. Without something clamping all of this together, the front end would have play, creak, and eventually fail under the stress of riding and landing tricks.
The compression system solves this. When set up correctly, it creates a solid, rattle-free front end that responds precisely to rider input. When set up incorrectly — or when incompatible parts are combined — the result ranges from annoying creaking to structural failure mid-session.
New to freestyle scooters? Start with our beginner's guide to choosing a pro scooter before diving into compression systems.
What Is Part of the Compression System?
The compression system is not just one component. It involves:
- Bars
- Bar clamp
- Headset bearings (integrated or non-integrated)
- Deck (specifically the headtube)
- Fork
Understanding how these parts interact is the foundation of building or upgrading a custom scooter correctly.
Headset Bearings: Integrated vs Non-Integrated
Headset bearings sit inside the headtube of the deck and allow the fork to rotate smoothly.
Non-integrated headsets consist of cups pressed into the headtube, with separate bearing races, bearings, and dust covers. They are found on older and entry-level decks.
Integrated headsets use bearings that sit directly in a machined recess inside the headtube, with no cups required. The vast majority of modern freestyle scooter decks use integrated headsets — they are lighter, lower-profile, and easier to service.
A Note on Maintenance
Every compression system wears over time and requires regular attention. If you notice play, creaking, or grinding near the front wheel — and tightening the clamp and compression bolt does not resolve it — the headset bearings likely need replacing.
Overtightened or neglected compression wears out significantly faster. Check your compression before every session.
The Five Compression Systems
1. Threaded Fork Compression
The oldest and most basic system. Found on entry-level and non-freestyle scooters — the kind sold in general sports shops. The fork steerer tube is threaded, and a threaded nut compresses the headset from above. The bars have a slit.
This system is not designed for trick riding. If you see it on a scooter marketed as a freestyle or stunt scooter, walk away. It is not suitable for skatepark use.
2. ICS — Inverted Compression System
ICS was one of the first purpose-built compression systems for freestyle scootering. It was popular in the early years of the sport but has largely disappeared from the modern market — and for good reason.
How it works:
A compression bolt threads upward from below the fork — meaning the front wheel must be removed to access and tighten it. Inside the bars, a star nut (sometimes called a "daisy") is pre-installed or added separately. The bolt threads into this nut, pulling the fork up into the headtube. A separate bar clamp with a slit holds the bars in place.
Key characteristics:
- Bolt tightens from below — wheel removal required for adjustment
- Requires a star nut inside the bars
- Lightest system available
- Uses non-standard bolt sizes on some brands (Ethic uses 10mm bolts)
Pros: Very light weight
Cons: Extremely inconvenient to service, requires regular re-tightening, very limited modern compatibility
ICS is a dead end for new builds. If your current scooter runs ICS, it is worth considering an upgrade to a more serviceable system.
3. SCS — Standard Compression System
SCS is the most robust and reliable compression system in freestyle scootering. It replaces both the internal compression hardware and the bar clamp with a single external unit.
How it works:
An SCS clamp slides over the outside of the fork steerer tube. Inside the clamp sits a washer (sometimes called a "puck") and a compression bolt, which threads into the top of the fork steerer tube. The bars insert into the upper half of the SCS clamp. Two sets of bolts — one set compressing the fork, one set clamping the bars — are tightened independently.
Key characteristics:
- External clamp — no internal hardware required in the fork
- Replaces the bar clamp entirely
- Bars must have no slit (a slit bar will deform under SCS clamping pressure — unless an SCS adapter is inserted)
- Compatible with oversized bars (34.9mm external diameter) and standard bars (31.8mm) — most SCS clamps include a reducing shim for standard bars
- Some compact SCS clamps are compatible with standard diameter bars only — check before buying
- Fork steerer tube diameter for SCS/HIC forks: 28.7mm
Pros: Maximum strength, easiest to service, widest bar compatibility, no slit required
Cons: Heaviest system, largest physical footprint
We recommend SCS without reservation for most riders, especially those building their first custom setup. It offers the best combination of reliability, ease of maintenance, and compatibility.
4. HIC — Hidden Internal Compression
HIC uses an oversized fork steerer tube and an internal compression sleeve (called a collet or HIC sleeve) to create a strong, hidden connection between the fork and bars.
How it works:
The fork steerer tube has a larger diameter than IHC (28.7mm external, compatible with SCS/HIC forks). A HIC sleeve — a cylindrical insert with a washer and compression bolt — is placed inside the steerer tube. The bars, which must be oversized (34.9mm external diameter) and have a slit, slide down over the outside of the steerer tube. The bar clamp then clamps the bars against the steerer tube.
Key characteristics:
- Oversized steerer tube (28.7mm) — same fork type as SCS
- Bars must be oversized (34.9mm) and have a slit
- Compatible bar materials: steel or titanium only
- HIC sleeve rarely included with forks — usually purchased separately
- Bar clamp is separate (typically 2-bolt, though 1, 3, and 4-bolt variants exist)
Pros: Strong connection, lighter than SCS, same fork compatible with SCS
Cons: Limited bar compatibility (oversized steel or titanium with slit only), HIC sleeve often sold separately, less common than IHC or SCS
5. IHC — Integrated Hidden Compression
IHC is the most widely used compression system on modern complete scooters and a common choice for custom builds. It functions on the same principle as HIC but uses a narrower fork steerer tube, reducing weight.
How it works:
The IHC fork has a narrower steerer tube (~25mm diameter). An IHC collet — similar to the HIC sleeve but sized for the narrower steerer — is inserted inside the steerer tube with a washer and compression bolt. The bars slide down over the outside of the steerer tube and are held by a separate bar clamp.
Key characteristics:
- Narrower steerer tube (~25mm) — IHC-specific forks only
- Bars must have a slit
- Compatible bars: steel 31.8mm (standard) or aluminium 34.9mm (oversized)
- Bar clamp: HIC/IHC clamp, 31.8mm or 34.9mm depending on bar diameter
- IHC collet typically included with IHC forks
- Most complete scooters currently use IHC
Pros: Lighter than HIC and SCS, wide availability, most complete scooters use it
Cons: Narrower steerer tube is slightly less strong than HIC, slit required in bars, aluminium bars only in oversized diameter
Quick Comparison
| Threaded | ICS | SCS | HIC | IHC | |
|---|---|---|---|---|---|
| Weight | Medium | Lightest | Heaviest | Light | Lightest (among modern systems) |
| Strength | Poor | Poor | Maximum | Very good | Good |
| Bar slit required | Yes | Yes | No | Yes | Yes |
| Modern availability | Entry-level only | Rare | Excellent | Good | Excellent |
| Recommended for | — | — | Most riders | Heavier/aggressive riders | Complete scooters, light builds |
Which System Should You Choose?
SCS is the safest choice for most riders building a custom setup — maximum strength, easiest maintenance, widest bar compatibility, and no need to worry about slit compatibility.
IHC makes sense if weight is a priority and you are comfortable with the narrower steerer tube and slit requirement. It is the standard on most complete scooters.
HIC occupies a middle ground — stronger than IHC, lighter than SCS, but with more restrictive bar compatibility (oversized steel or titanium only).
ICS and threaded are not recommended for any new build or serious riding.
Still Have Questions?
Compression compatibility is one of the most common sources of mistakes when building a custom scooter. If you are not sure which system works with your existing parts — or which to choose for a new build — contact us via WhatsApp or Telegram at +995 595 417 489 before you buy. We will help you get it right.
For a detailed breakdown of which forks, bars, and clamps are compatible with each compression system, see our Compression Compatibility Guide.
Browse our full range of forks, bar clamps, and bars at ProScooter.Shop.
This article was last updated in April 2026. If you have spotted an error or have a question about a specific setup, get in touch — we update this guide regularly.
