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 sponsors professional road and mountain-bike race 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 →