Campagnolo Cassette Lockring Tool

Campagnolo's cassette lockring uses a different splined pattern from Shimano and SRAM, and the difference is enough that an HG-pattern tool slips and rounds the splines on contact. The 1670.4/4 is the Unior socket sized to the Campagnolo lockring, with a 24 mm wrench flat and a 1/2" drive on the opposite face; the same back-end format as the rest of our cassette-lockring family, just with the Campy-pattern engagement.

Workshops that service Italian road bikes need this tool in the drawer. Campagnolo Record, Chorus, Centaur, and Athena cassettes from 9-speed through current Super Record EPS 12-speed all use the Campagnolo lockring pattern. Fulcrum wheels (Campagnolo's wheelset division) ship with the same lockring on freehub-equipped wheelsets. Campagnolo Ekar 13-speed gravel cassettes use a different freehub interface but retain the Campagnolo-pattern lockring on top.

How to use it

Procedure is the same as the Shimano/SRAM workflow: hold the cassette still with a chain whip on one of the larger cogs, register the 1670.4/4 in the lockring, and turn counter-clockwise with a 1/2" ratchet or a 24 mm wrench. Campagnolo publishes 50 Nm as the lockring torque spec; a touch higher than Shimano/SRAM's 40 Nm; so expect the break-free to take a firm motion.

If you're servicing both Shimano/SRAM and Campagnolo cassettes regularly, the 1670.4/4 lives next to the 1670.5/4 in the cassette-tool tray. The two sockets are sized to different splined patterns; mixing them up wastes splines. Mark one with paint or tape on the body if your bench tends toward fast service.

Compatibility

• Campagnolo cassettes, 9-speed through 12-speed (Veloce, Centaur, Chorus, Record, Super Record)
• Campagnolo Ekar 13-speed gravel cassettes (Campagnolo lockring pattern is retained)
• Fulcrum wheelsets with Campagnolo-spline freehubs
• Not for Shimano or SRAM cassettes (use 1670.5/4, 1670.7/4, 1670.8/2BI-US, or 1670.9/4)

Specs

• Campagnolo splined lockring pattern
• 24 mm hex wrench flat
• 1/2" square drive socket on the opposite face
• Trivalent chrome plated to ISO 1456:2009
• Article number: 1670.4/4

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. Campagnolo and Unior are both European heritage brands that have kept manufacturing close to home; Vicenza for Campagnolo, Zreče for Unior. The 1670.4/4 is what happens when a Slovenian forge builds the tool for an Italian groupset: same materials, same trivalent-chrome finish, same construction call as the rest of the Unior cassette-lockring line, with the engagement pattern that matches the Campagnolo cassette on the bench.

Pro tip from our mechanics

Campagnolo lockrings retain a 12-tooth small cog as the catalog's lower limit on current 11- and 12-speed cassettes, which keeps the chain-whip workflow simple; our Multispeed Chainwhip 1660/2DP-US covers 6-12 speed cogs and pairs with the 1670.4/4 directly. Ekar 13-speed cassettes do drop below 12 teeth on the small cog (9 or 10 tooth depending on the option), where a chain whip won't seat; the Cassette Wrench X Range was sized for SRAM 10t but covers the Ekar small-cog range as well. The cassette-replacement workflow walks through the chain-whip-versus-cassette-wrench decision: When and how to replace your cassette →