Axle Adaptor

A thru-axle hub will not rest in a Unior truing stand the way a quick-release or solid axle does. Axle Adaptor 1689.3 is the official magnetic pair that locates 12, 15 and 20 mm thru-axles on the stand uprights.

Each adaptor is a short cone with a magnet on the back. Drop one into the top of each upright, snug the bolt so it cannot walk, then set the wheel so the axle ends sit in the cones. Take the wheel off and the magnets hold the pair anywhere on the stand until the next job.

The current Pro Truing Stand 1689 already ships with this pair. Buy this listing as a spare: a lost cone, a second bench, or a Portable Truing Stand 1688, whose official instruction manual names 1689.3 as the extra for 12, 15 or 20 mm axles. The 1688 product page and datasheet do not repeat that list; the manual is the source.

This is not the Cannondale Lefty adaptor. Lefty front hubs are asymmetric and need article 1689.6. 1689.3 is the standard thru-axle pair.

Compatibility

• 12, 15 and 20 mm thru-axle standards. One pair covers all three.
• Pro Truing Stand 1689. Unior lists 1689.3 as an accessory; the current stand includes the pair.
• Portable Truing Stand 1688. The official 1688 instruction manual names 1689.3 as a spare for 12, 15 or 20 mm axles.
• Not for Cannondale Lefty hubs. Those use adaptor 1689.6.

Specs

• Article 1689.3, code 629321
• Two pieces in the set
• Diameter (D) 22 mm
• Length (L) 20 mm
• Weight 57 g
• Magnetic so they park on the stand when not in use
• Bolts hold them on the uprights in use
• Official page carries Unior's lifetime-warranty and trivalent-chrome profile badges

All listed dimensions are in millimetres and may vary in tolerance. Weight is in grams.

Built in Zreče, Slovenia

Unior has been forging hand tools in Zreče since 1919, and sponsors professional road and mountain-bike race teams. The 1689.3 pair is the small part that lets a modern thru-axle wheel use the same stand as a quick-release wheel.

Pro Tip

Seat the axle fully in both cones and keep the bolts snug before you read the rim. A cone that can tilt is a wheel that reads false. The stand procedure is in How to True a Bike Wheel.

FAQ

What axle sizes does the 1689.3 fit? Unior publishes three: 12, 15 and 20 mm thru-axle standards. The official table is a two-piece set, so one pair covers all three sizes. It is not a per-diameter kit.

Which truing stands does it fit? Unior lists 1689.3 as an accessory of the Pro Truing Stand 1689. The official 1688 instruction manual names 1689.3 as the spare for 12, 15 or 20 mm axles. The 1688 product page and datasheet do not repeat that list.

Does the Pro Truing Stand 1689 already include these? The current 1689 (code 629297) ships with the conical magnetic pair. This listing is the spare pair, code 629321, for a lost cone, a second bench, or a 1688 that never included adapters.

What are the official dimensions, and is this the Lefty adaptor? Diameter 22 mm, length 20 mm, weight 57 g, two pieces. Cannondale Lefty front hubs need article 1689.6, not 1689.3. Unior says Lefty wheels cannot sit on the stand with the usual adaptors.