Hub Genie

Modern thru-axle hubs use removable end caps to convert between axle standards. The same hub body services a 12 mm thru-axle when fitted with 12 mm caps, a 15 mm thru-axle with 15 mm caps, and so on. Swapping the caps is the easy part on a new hub; pulling the caps off after a few seasons of road grime working its way into the cap-to-bore interface is what stops a lot of mechanics from doing the swap at all. Prying a cap off with a flat-blade screwdriver is the field-mechanic answer, and it marks up the cap's face every time. The Hub Genie pulls the cap from inside without contacting the cap's outer face.

How it works

The Hub Genie has an expanding mechanism in its working end that grips the cap from the cap's inside diameter. The mechanism opens against the cap's interior wall, applies even pressure across the cap's full inside circumference, and the puller draws the cap straight out with no contact on the cap's outer face. The cap comes off unmarred; the hub bore comes through the operation unscratched.

The tool's mechanical advantage comes from a sliding handle and the expanding-collet grip; no hammering, no prying, no lateral load on the cap. Modern hub caps that have been seated by years of corrosion still release cleanly when the expanding mechanism is applied along the cap's axis of removal.

Two versions

The Hub Genie ships in two configurations sized to current axle standards:

• Smaller version: 12 mm and 15 mm thru-axle hubs
• Larger version: 20 mm thru-axle hubs

Both versions feature plastic-dipped handles for grip under load. The handle geometry stays comfortable across long shop sessions where multiple hub services queue up.

Compatibility

The Hub Genie engages on the cap's inside diameter, which is the engagement surface that's standardized across most current thru-axle hub designs. It works on DT Swiss, Industry Nine, Hope, Chris King, and most aftermarket thru-axle hubs in the 12, 15, and 20 mm axle envelopes. Quick-release hubs (9 mm front, 10 mm rear) use a different engagement style and are not the use case for the Hub Genie; see the Axle Vise 1639/2 for that workflow.

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 Hub Genie is the kind of Unior tool that exists because the alternative (prying caps off with a screwdriver) was the workshop default for years and quietly destroyed a lot of hub caps. The expanding-from-inside mechanism is the design move that makes the tool the right answer to a stuck cap.

Pro tip from our mechanics

When a cap is severely stuck, give the cap an overnight soak in penetrating oil before reaching for any tool. The corrosion that holds a cap in place is most often where the cap's seal lip has fused to the hub bore; breaking that fusion with penetrating oil makes the Hub Genie's clean axial pull work the first time. Forcing a stuck cap with any tool risks shearing the seal lip and turning a clean cap-swap into a hub rebuild. The hub-service context for this tool: Bearing and headset service: a workshop guide →