Over Axle Bearing Press Set

Current hub designs put a step in the axle where the bearing sits. The axle is fatter through the bearing seat (12 mm or 15 mm or 17 mm or 20 mm, depending on the standard) and steps down at the shoulder so the bearing's inner race butts against the shoulder rather than against the hub shell. The design is structurally clean and stiff, but it defeats the standard bearing press. A drift sized to seat against the bearing's outer race can't pass over the axle's larger-diameter section, so the standard 1721 drift set has nowhere to land. The Over Axle Bearing Press Set is the adapter set that extends the 1721 press into shouldered-axle hub territory. How it works The set adds two pieces to every press stroke: an axle-side adapter (sized to clear the axle's largest diameter) and a bearing-side adapter (sized to the bearing's OD). The axle adapter slides over the axle, the bearing adapter sits on the bearing's outer race, and the press shaft drives them together. The bearing seats on its shoulder without the press hardware ever touching the axle's stepped section. The set covers the full modern axle envelope and the bearing ODs paired with each axle size: Axle diameter Bearings covered 10 mm 6000, 6900 12 mm 6001, 6801, 6901 15 mm 6802, 15267, 6902, 6002 17 mm 6803, 1728, 6003 18 mm 6903/18 20 mm 6804, 6904 Each axle and bearing size gets a pair of adapters (axle-side and bearing-side), so the set covers every combination without forcing a mid-job tool swap. Spacers The set includes spacers for the 10 mm, 15 mm, 17 mm, and 20 mm axle envelopes: Spacer 10 × 40 Spacer 15 × 45 Spacer 17 × 45 Spacer 20 × 45 The spacers make up the working length needed when the bearing seat is recessed deep in the hub shell and the standard adapter won't reach. Workshop-side notes Each drift is laser-etched with its size, so identifying the right adapter at the bench is a glance instead of a measurement. The etching survives the cleaning cycles that wear painted labels off. The set is an extension of the Bearing Press Set 1721, not a standalone tool. The 1721 press body is required; the over-axle set adds the adapter coverage on top. The set works with the Quick-release Handle 1721.3 for shops running daily bearing changes on shouldered-axle hubs. 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. The over-axle set is the upgrade that takes a standard 1721 press into the modern thru-axle MTB and gravel hub world. Built to the same dimensional tolerance as the original drifts, the adapters extend the press without changing the load path or working spec. Pro tip from our mechanics The biggest workflow gain from the over-axle set is the laser-etched labels. We used to keep a chart taped above the press bench mapping bearing numbers to drift sizes; with the labels stamped on the adapters themselves, the chart goes away. Match the bearing number on the new bearing to the etched number on the adapter, drop it on the axle, and press. Where this fits in the press workflow: Bearing and headset service: a workshop guide → FAQ What does the Over Axle Bearing Press Set add to a standard bearing press? It adds paired adapters that let the press work on hubs with a stepped (shouldered) axle. The axle-side adapter clears the axle's largest diameter and the bearing-side adapter sits on the bearing's outer race, so the bearing seats against its shoulder while the press hardware never contacts the axle. It extends the 1721 press rather than replacing it. Which axle and bearing sizes does it cover? It covers the modern through-axle range — 10, 12, 15, 17, 18 and 20 mm axle diameters — and the cartridge-bearing outer diameters paired with each axle size (for example 6902 and 6002 on a 15 mm axle, or 6804 and 6904 on a 20 mm axle). Each axle-and-bearing combination gets its own axle-side and bearing-side adapter pair. Do I still need the 1721 bearing press? Yes. This is an adapter set, not a standalone press. The adapters ride on the 1721 press shaft and hardware; they are what let that press reach shouldered through-axle hubs a standard drift can't seat against.