Universal Bearing Press

Cartridge bearings live in three places on a modern bike: the headset, the bottom bracket, and (for some hub designs) the rear hub. A press-fit bearing has to go in square and seated fully on its outer race, every time. Push it in cocked and the bearing binds and wears out in a season; push it through the inner race and you crush the seal and contaminate the grease before the bike leaves the stand. The Universal Bearing Press 1721 is the bench tool that gets the operation right.

What the tool does

The 1721 is a threaded-shaft press with a handle on one end and a drift on the other. Choose the drift sized to the bearing's outer race diameter, slip it onto the press shaft, and draw the bearing into its bore by turning the handle. Steady, controlled pressure throughout; no hammering, no chance of glancing the drift off-axis. The force transmits through the drift to the bearing's outer race only, which is what keeps the seal between the two races intact. Force through the inner race crushes the seal and contaminates the grease before the bike leaves the stand. A bearing whose grease is contaminated at install isn't a long-term bearing.

The 1721 ships with a drift assortment sized for the common bearing outside-diameter range across headset cartridges, external BB cup bearings, and most hubs. The drifts live in a laser-cut SOS foam tray inside a plastic case, so they stay paired with the press and don't migrate into the bench drawer. The size match is what “universal” means here: the right drift for the bearing, not a generic mid-size that might or might not bear on the right surface.

Specs

• Operation: threaded-shaft press, hand-driven
• Drift set: sized for the common bearing OD range across headset, BB, and hub bearings
• Storage: laser-cut SOS foam tray in a plastic case
• Pairs with our Bearing Puller for the other half of the operation
• Made in Slovenia by Unior

Includes: Press body, threaded shaft, handle, full drift assortment in the foam tray.

Made in Slovenia, since 1919

Unior has been forging hand tools in Zreče since 1919, and is the official technical partner of multiple World Tour and downhill teams. The 1721's drift set is the load-bearing decision in the design; a press without the right drifts is a press that bottoms out on the wrong surface. Unior makes the drifts and the press together so the kit fits the bearings the catalog actually services.

Pro tip from our mechanics

When the press resistance suddenly stiffens, the bearing is bottomed in its bore. Stop. A few more turns past bottom doesn't make the bearing more seated; it just compresses the cup or shell against whatever face is on the other side, which (for a headset) is the face you carefully prepped with the head-tube reamer and facer earlier in the same build. Press to the bottom, stop, back the press off, move on.

The outer-race rule is the load-bearing principle, and the chain-position is the procedural detail. The principle, plus the broader headset prep workflow the 1721 sits inside, is in our walk-through: Frame prep: head tube, crown race, and star nut work →