Profile Design Threadless Headset Converter

This component allows you to replace your bike's old-fashioned quill stem with a modern threadless stem. It essentially adapts your vintage threaded fork to accept standard 1-1/8 inch threadless stems and handlebars, giving you access to a much wider range of modern cockpit parts.

You need to check the diameter of your current threaded steerer tube. This converter is designed to work with either 1-inch or 1-1/8 inch threaded steerer tubes, allowing you to upgrade to a 1-1/8 inch threadless stem in either case.

Installation is straightforward and generally requires only standard bicycle tools, such as a set of hex keys. You will need to remove your existing quill stem and handlebars, slide the converter into the steerer tube, and tighten it down before installing your new stem.

While the converter itself doesn't change the bike's geometry, the modern stem and handlebar you choose to install likely will. Moving to a threadless setup often provides a stiffer, more responsive front end compared to traditional quill stems, which can make the steering feel more precise.

No, this converter is intended for use with metal (steel or aluminum) threaded steerer tubes. It is not compatible with carbon fiber steerers, which require specific expander plugs and different installation methods.