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 is the official Cannondale Lefty adaptor for the Pro Truing Stand 1689 (not listed for the Portable Truing Stand 1688). Official hub fitment is Lefty 50 (standard hub) and Lefty 60 (Supermax hub).

Compatibility

• Hubs: Lefty 50 (standard hub) and Lefty 60 (Supermax hub).
• Unior lists this adaptor on the 1689 page, not on the 1688 page: Pro Truing Stand 1689, Portable Truing Stand 1688.
• Weight: 80 g. Article 1689.6, code 623450.

Specs

• Interface: dedicated adaptor for Lefty 50 standard hubs and Lefty 60 Supermax hubs.
• Official accessory of the Pro Truing Stand 1689. Not named on the 1688 page, datasheet, or instruction manual.

Built in Zreče, Slovenia

Unior has been forging hand tools in Zreče since 1919, and sponsors professional road and mountain-bike race 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 →

FAQ

What does the 1689.6 do? It is Unior's Cannondale Lefty adaptor for the Pro Truing Stand 1689. Cannondale Lefty front wheels have an asymmetric hub, so they will not sit on the centering stand with the usual adaptors.

Which Lefty hubs does it fit? Unior publishes two: Lefty 50 (standard hub) and Lefty 60 (Supermax hub). Other Cannondale fork names are not in the official listing; if the hub is not one of those two, this adaptor is not claimed to fit it.

Does it fit the 1688 portable truing stand? Unior lists 1689.6 as an accessory of the Pro Truing Stand 1689. The 1688 product page, datasheet, and instruction manual do not name 1689.6. The 1688 manual does name 1689.2 and 1689.3 as extras. We do not claim 1688 fitment.

What is the article number and weight? Article 1689.6, code 623450, weight 80 g. The official product page carries Unior's lifetime-warranty profile. No spare parts are listed for this adaptor.