If you're rebuilding a headset on a frame with a semi-integrated ZS44 head tube, this is the upper assembly Ritchey sells to replace the bearing, cup, and top cap as a unit. The Classic Semi-Integrated ZS Upper Headset from Ritchey works with frames that accept a 44mm ZS-standard upper bearing and a 1-1/8" (28.6mm) fork steerer — a configuration you'll find on a lot of road and gravel bikes built over the last fifteen years, including Ritchey's own Road Logic and Outback. The "PF" in the Excel SKU refers to the press-fit ZS interface, where the bearing seats into a machined recess in the head tube rather than riding on an external cup.

The bearing itself is a full-complement stainless steel angular contact cartridge — 41.0mm OD, 30.15mm ID, 7mm tall, with 45°/45° contact angles — packed with Ritchey's high-webbing grease from the factory. Sealed cartridge construction means you're not repacking loose bearings; when service interval rolls around, you pull the cartridge and drop in a new one. The 41mm outer diameter is the standard ZS44 spec, so this drops into any frame built to that interface.

Stack height is 10.1mm, which matters if you're rebuilding around a specific spacer stack or trying to match an existing front-end height. Top cap is included, and the alloy construction comes in Ritchey's high-polish silver finish — the same look that pairs naturally with their Classic stem and seatpost line if you're building a coordinated cockpit. Pair this with the matching Classic lower headset for your frame's lower bearing spec (ZS44/30 is the common road match) to complete the rebuild.... Read More