External cup headsets follow the original mountain bike standard that predates integrated and internal designs—the cups press into a head tube with a 34mm bore and sit proud of the frame rather than recessing into machined seats. The Ritchey Comp Upper Headset External Cup handles the upper position in this arrangement, accepting a standard 1-1/8" steerer tube through its EC34/28.6 interface. This matters for frame replacement builds, vintage restorations, or any situation where you're working with a head tube that wasn't machined for modern zero-stack or integrated bearing seats.

The external cup design places the cartridge bearing inside a pressed steel cup that installs into the head tube bore using standard headset press tooling. Once seated, the cup lip rests against the head tube face, creating a positive stop that prevents migration under load. Ritchey specs this unit with their standard cartridge bearings—serviceable units that can be replaced independently of the cups when they eventually wear. The steel construction handles the compression loads that headsets see without the weight penalty becoming significant, since we're talking about a component that lives in a non-rotating application where material mass doesn't affect ride quality.

Installation requires a headset press to seat the cup squarely into the head tube—attempting to hammer it in risks cocking the cup and damaging the bearing seat. The 28.6mm bore accepts standard 1-1/8" steerers, which covers the vast majority of rigid and suspension forks designed for external cup head tubes. If you're building up an older frame or replacing a worn upper cup on a bike that predates the integrated headset era, this is the interface standard you're working with.... Read More