71806 LLB Enduro Angular Contact Headset Bearing 30mm x 42mm x 7mm Shields while the inner ring is

while the inner ring is without a flange

D 52 mm Outside diameter

Outer Dia de: 230mm

TSN518 S Labyrinth seals

though the MAX-type version of this bearing is better suited for suspension use

71806 LLB Enduro Angular Contact Headset Bearing 30mm x 42mm x 7mm Shields while the inner ring isEnduro's ABEC 5 is the next performance step up from the popular ABEC 3 range. By using military level, high precision HRC 64 hardended Grade 5 Chromium Steel Balls, and 52100 High Carbon Chromium Alloy mirror polished races. This combination allows Enduro's ABEC 5 bearings to use tolerances twice as tight as ABEC 3, and operate without any noise. The Graphite Nylon ball retainers allow virtually frictionless movement and provide constant lubrication