The Enduro Angular Contact Headset Bearing is a high-performance replacement designed for integrated and semi-integrated headsets requiring a specific 30.5mm internal diameter. While standard 1 1/8" bearings typically measure 30.15mm, this specialized 30.5mm variant is the critical "problem solver" for certain frame and fork standards that utilize a slightly larger steerer interface. By providing a precision fit, this bearing eliminates the microscopic movement that causes headset "creaking" and premature wear in specialized systems.
As an Angular Contact (ACB) bearing, it features a 45° internal and 45° external chamfer. This geometry is essential for modern bicycles, as it allows the bearing to center itself perfectly within the head tube and against the compression ring. This design efficiently handles the simultaneous vertical impacts and lateral steering forces of high-speed riding, ensuring that your front end stays tight, responsive, and noise-free.
45° x 45° Angular Contact: Specifically engineered to manage combined radial and axial loads, providing a stable steering platform and preventing the "notchy" feel common in lower-grade bearings.
52100 High-Carbon Steel Races: Forged and vacuum-degassed for ultimate purity, resulting in a harder, smoother surface that resists pitting and wear under heavy loads.
Grade 10 High-Precision Balls: Features balls that are spherical within 10/1,000,000" of a perfect sphere, ensuring a friction-free rotation and perfectly even load distribution.
Dual-Lip Labyrinth Seals: Equipped with high-contact seals that provide a robust barrier against road spray, dust, and moisture while locking in the high-quality factory grease.
Specialized 30.5mm ID: A specific "niche" size that ensures a perfect, play-free fit for manufacturers using this oversized 1 1/8" standard.
High-Fill Waterproof Grease: Factory-packed with specialized lubricant designed to stay in place under high vibration and resist wash-out during cleaning.
| Feature | Specification |
| Dimensions | 30.5mm (ID) x 41.8mm (OD) x 6.5mm (W) |
| Contact Angle | 45° Internal / 45° External |
| Material | 52100 High-Carbon Chromium Steel |
| Bearing Type | Angular Contact (ACB) |
| Seal Type | Dual-Lip High-Contact |
| Precision Grade | ABEC 3 |
Owners of Specialized Headsets: If your old bearing is marked 30.5mm, this is the exact replacement needed to maintain the structural integrity and silence of your front end.
Restoring Steering Feel: Ideal for riders looking to eliminate "slop" or play in their headset that standard-sized bearings cannot fix.
Performance Maintenance: A high-quality, professional-grade solution for annual headset refreshes on performance road and gravel bikes.
Standard 1 1/8" Steerers: The vast majority of 1 1/8" headsets use a 30.15mm bearing. If you force this 30.5mm bearing onto a standard fork, it will result in play that cannot be tuned out.
Extreme Corrosive Environments: While highly durable, this is a chromium steel bearing. For riders who train heavily indoors or live on the coast, the Enduro Stainless Steel series offers superior rust resistance.
The 30.5mm internal diameter is a rare but vital measurement. Always use a digital caliper to verify your old bearing or steerer tube diameter before installation. To ensure a silent ride, apply a thin, even layer of waterproof assembly grease to the chamfered edges and the headset cups. This prevents the metal-on-metal micro-vibrations that lead to annoying creaks. When setting your headset tension, tighten the top cap only until there is no fore-and-aft movement in the fork—over-tightening is the primary cause of premature wear in angular contact bearings!
