BLB Fork Shim - 1" to 1-1/8"

If you have an older frame with an unthreaded 1-inch fork but want to use a more modern 1 1/8-inch A-head stem, the BLB Fork Shim is the simple solution. The two semicircular shims fit around the steerer tube and increase its diameter from 25.4 to 28.6 mm, allowing the stem to clamp securely in place.

This is especially useful as a small component when converting or upgrading an older track, fixed-gear, or road bike without wanting to replace the fork just to use a different stem. It's particularly well suited to builds where you want to combine an older 1-inch standard with the much wider selection of 1 1/8-inch A-head stems.

The shims are 50 mm tall, which is longer than the clamp height of many stems. They may therefore protrude above the stem, depending on your cockpit setup. Check the stem's clamp height and how much steerer tube you have available before installation.

A very simple part, but sometimes exactly what's needed to make old and new standards work together.

Quick Specs

• Type: Steerer tube shim for A-head stem
• Steerer tube: 1" / 25.4 mm
• Stem: 1 1/8" / 28.6 mm
• Height: 50 mm
• Design: Two semicircular metal shims
• Use: Allows you to install a 1 1/8" A-head stem on an unthreaded 1" steerer tube
• Does not fit: Threaded 1" forks with a traditional quill stem