Zero Bearing 40x52x7mm 45°/45° R413
What Is It?
The Zero Bearing R413 40x52x7mm 45°/45° is a sealed angular-contact headset cartridge bearing used in bicycle headsets (road, MTB, gravel, and XC bikes). It sits inside the headset cup and allows the fork steerer to rotate smoothly while handling steering loads and impacts.
This specific size is commonly used in integrated or semi-integrated headset systems, especially on frames that require a 40mm inner diameter / 52mm outer diameter lower bearing standard.
Key Features
- Sealed cartridge headset bearing (maintenance-free design)
- 45°/45° angular contact geometry for smooth steering and load distribution
- Fully sealed to resist water, dust, and mud ingress
- Designed for integrated headset systems (IS / ZS / EC variants depending on frame)
- High durability steel construction
- Direct replacement style bearing (drop-in fit)
- Smooth low-friction steering performance
Specifications
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Model: R413
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Inner Diameter (ID): 40mm
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Outer Diameter (OD): 52mm
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Thickness: 7mm
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Contact Angle: 45° / 45°
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Type: Sealed angular contact cartridge bearing
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Application: Bicycle headset (lower bearing common use)
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Material: Hardened steel with sealed races
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Compatibility: Frames requiring 40x52x7 45/45 headset bearings (often integrated lower headset cups)
Who Is It Suitable For?
- Mountain bikers (XC / trail / light enduro)
- Road cyclists with integrated headset systems
- Gravel riders needing reliable steering performance
- Bike mechanics replacing worn headset bearings
- Riders experiencing:
- notchy steering
- headset play
- corrosion or rough headset rotation
Who Should Use It?
- Riders servicing or rebuilding a headset with this exact size spec
- Cyclists replacing rusted or worn lower headset bearings
- Bike builders working with frames that specify IS52/40 or similar standards
- Anyone needing a precise replacement for a 40x52x7 45°/45° angular-contact bearing
Important Fitment Note
Even though the size is standardized:
- The 45°/45° angle MUST match your frame’s crown race and headset cup
- A correct physical size but wrong angle can cause:
- poor steering feel
- premature wear
- headset play or binding
