Handlebar height comes down to spacer stack, and 15mm makes a noticeable difference in reach and back angle. The Wheels Manufacturing Aluminum Headset Spacer gives you that adjustment range in a single piece rather than stacking multiple thinner spacers that can shift out of alignment over time. At 15mm, this spacer works well as a primary stack builder when you need significant height above the headset, or as an addition to an existing setup when fine-tuning fit after a stem swap or position change.

The spacer fits standard 1-1/8" threadless steerer tubes with a 28.9mm inner diameter that matches the steerer specification used across road, gravel, and mountain bikes. The 34.4mm outer diameter sits flush with most headset top caps and stems for a clean transition in the cockpit stack. Precision machining keeps the faces parallel so the spacer sits flat against the headset bearing cover below and the stem or additional spacers above, which matters for proper headset preload.

Wheels Manufacturing machines these from aluminum and applies a black anodized finish that resists scratches and corrosion. The anodizing also prevents the spacer from marking up your steerer tube during installation or adjustment. Unlike carbon spacers that can crack under overtorque or if the stem bolts are unevenly tightened, aluminum handles the clamping forces without concern.... Read More