Specialized Headset Road Upper/Lower Bearing

Head tube bearings are the quietest failure on a bike until they aren't. Grit works past the seal, the grease washes out, and suddenly there's a notch at dead center and a knock under braking. The Road Headset Bearing, 49.5mm from Specialized is the factory service part for that job across a long list of road, gravel, and cross-country platforms — a single sealed cartridge measuring 49.5mm OD x 40.5mm ID x 6.5mm thick, with a 45x45-degree contact angle on both faces.

That 45x45 geometry is the Campagnolo-style integrated standard, which means the bearing drops straight into the head tube with no cups and seats against the frame's molded race. Construction is steel, which is what Specialized specs from the factory on these frames. The 6.5mm width matters as much as the diameters here — stack it against a 7mm bearing from a parts drawer and the compression math at the top cap changes, so verify the thickness before ordering if you're measuring an old bearing rather than matching the part number.

Where this bearing lands in the stack depends on the frame. On Tarmac SL8, SL9, and Aethos 2, it serves as either the upper or the lower. On Crux, Crux 5 and the original Aethos, it's the lower bearing. On Epic 8 and 9, it's the upper. The compatibility list runs deep — Tarmac SL7 and SL8, Aethos and Aethos 2, Crux and Crux DSW, Allez Sprint, Epic 8 and Epic World Cup, and back through the Venge line to the ViAS era. If you own one of those frames, this is the number to write on the parts order.... Read More