Cannondale Lefty Hub Adaptor

Cannondale's Lefty fork is a single-sided design, which means its front hub is also single-sided: no off-side flange to anchor in a standard truing stand. Putting a Lefty wheel on a regular stand and hoping to true it is a non-starter; the stand has nowhere to clamp.

The 1689.6 closes that gap. It mounts in place of the standard hub clamp on the Pro Truing Stand 1689 or the Portable Truing Stand 1688 and gives the Lefty hub a one-sided anchor point that holds the wheel square to the stand's calipers. Standard Lefty and Supermax hubs both fit; the adapter accepts the Lefty's axle interface directly, no further machining required.

Compatibility

• Hubs: Cannondale Lefty (standard), Cannondale Supermax.
• Truing stands: Pro Truing Stand 1689, Portable Truing Stand 1688.
• Wheel range: the wheels the Lefty fork is designed for (verify against the specific Cannondale model if rebuilding from a stock wheelset).

Specs

• Interface: Lefty/Supermax-specific axle anchor.
• Mounts in place of the standard truing stand hub clamp.

Built in Zreče, Slovenia

Unior has been forging hand tools in Zreče since 1919, and is the official technical partner of multiple World Tour and downhill teams. Cannondale's Lefty has been on the market in one form or another since the late 1990s, and dedicated workshops servicing Lefty-equipped bikes have needed a truing-stand answer that long. The 1689.6 is that answer. Workshops that see a Lefty regularly stock the adapter as part of the standard truing-stand kit; workshops that see a Lefty rarely keep it on the back shelf and pull it out when one comes in.

Pro tip from our mechanics

Lefty wheels true the same way as any other wheel once the hub is anchored. The trap is the anchor itself. A Lefty hub that isn't fully seated in the adapter will read as a wheel that's out of true (it isn't; the hub is moving), and the resulting “truing” pass will introduce real lateral and radial error into a wheel that was true before you started. Seat the hub firmly in the adapter, check that it doesn't move when the wheel is rotated, then start the truing pass. The full workflow is in How to true a bike wheel →