What this headset is
A Press Fit / semi-integrated Ahead headset for standard 1 1/8" forks.
Brand: Syncros
Key Standards
-
Upper (top): ZS44/28.6
-
Lower (bottom): EC44/30
Meaning:
- Head tube:
- Top is a Zero Stack (ZS) 44 mm pressed cup
- Bottom is an External Cup (EC) 44 mm
- Fork:
- Straight steerer 1 1/8" (28.6 mm) or slightly tapered to 30 mm crown race
System type explained
ZS44/28.6 (Top)
- “Zero Stack” = bearing sits inside the frame
- Cup is pressed into the head tube
EC44/30 (Bottom)
- “External Cup” = bearing sits in a cup that extends outward
- Designed for larger crown race (30 mm)
What this means in plain terms
This headset is:
- ❌ NOT fully integrated (like IS44/IS52 systems you posted earlier)
- ❌ NOT for modern tapered 1.5" fork systems
- ✔️ Designed for older or classic 1 1/8" frames
- ✔️ Uses pressed cups (not drop-in bearings)
Key dimensions
- Head tube outer standard: 44 mm
- Bearing seat system: mixed ZS + EC
- Outer collar: 50 mm
- Material: forged/CNC aluminium cups
- Bearings: stainless steel, sealed cartridge
⚖️ Comparison with your other headsets
| System |
Type |
Top |
Bottom |
Fork |
Interchangeable? |
| This one |
ZS/EC |
ZS44 |
EC44 |
1 1/8" |
❌ |
| Addict/Solace |
IS |
IS41 |
IS46 |
1 1/4" |
❌ |
| Scale/Spark |
IS |
IS42 |
IS52 |
1 1/8–1.5" |
❌ |
| Foil 2023 |
IS |
IS44 |
IS52 |
1–1.5" |
❌ |
This is the key insight:
You now have 3 completely different headset families:
- IS (fully integrated drop-in)
- ZS/EC (semi-integrated pressed cups)
- Mixed road/MTB variants
Critical takeaway
This headset will only fit if your frame specifically uses:
- ZS44 top + EC44 bottom
- A 44 mm head tube system
- A 1 1/8" fork
It will NOT fit:
- Any Scott Foil system (IS44/IS52)
- Any Scale/Spark IS42 system
- Any Addict/Solace IS41 system
Simple rule to remember
- IS = drop-in bearings (modern Scott race bikes)
- ZS/EC = pressed cups (older / classic frames)
