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Shimano asks SRAM-owned Hammerhead to remove Di2 functions from its head unit

Published May 27, 2022

IRVINE, Calif. (BRAIN) — Hammerhead, the GPS cycling computer startup acquired by SRAM in January, says Shimano asked it to remove at least some Di2 functions from its Karoo 2 head units. 

Hammerhead announced the move in a post Thursday on the Support FAQ section of its website.  It was first reported on Shimano did not immediately respond to inquiries from BRAIN on Friday. A Hammerhead representative shared a company response below.

The Karoo 2 currently has functions that allow it to show the battery level of Shimano's Di2 system and to use the buttons on top of some Di2 road levers to switch screens on the head unit. Hammerhead said that with a software update next week, users will lose "a small subset" of Di2 functions. It indicated it is negotiating with Shimano to return the features. 

Shimano power meters will still connect wirelessly to Karoo 2 units.

Wahoo and Garmin head units have similar Di2 functions and there is no indication those functions are being removed. The Karoo 2 continues to integrate with SRAM AXS and Campagnolo electronic drivetrains.

When SRAM acquired Hammerhead the component brand said Karoo units would remain compatible with Shimano's components. "Together, SRAM and Hammerhead will continue to develop an innovative cycling technology platform ensuring riders can seamlessly integrate with a wide variety of existing hardware and software products and services including both Shimano and SRAM electronic shifting," SRAM said at the time. 

"Ultimately, Shimano identified SRAM as a competitor and the contract was terminated at Shimano’s request" — Hammerhead representative.

But the move away from integration apparently was initiated on the Shimano side, according to the Hammerhead representative:

"The changes come at the request of Shimano. Shimano provided a license agreement whereby Hammerhead was granted permission along with technical details enabling the connecting of the Hammerhead devices with the Di2 system. Hammerhead offered to continue supporting Di2 users with full functionality after the SRAM acquisition, but ultimately, Shimano identified SRAM as a competitor and the contract was terminated at Shimano’s request," the Hammerhead representative told BRAIN. "Hammerhead has reached out to Shimano and is open to resuming support of the functionality."

The representative continued: "Di2 will still work as a drivetrain, and Karoo will still work as a bike computer, and they both will work on the same bike. Affected customers lose all wireless connection between the Karoo and the Di2 system, and any Karoo functionality that depended on it, but nothing else."

The full FAQ statement:

Here at Hammerhead, we are committed to constantly improving in ways that benefit riders. With each update and integration, we chart an intentional path of continuous improvement.

Unfortunately, we don't always have the ability to supply every product integration we want for our riders. At the request of Shimano, effective with next Thursday’s software update on June 2nd, riders who utilized Di2 integration will lose access to a small subset of features. The update will remove on-screen battery status and shifter mode data, front and rear derailleur indications, and Karoo screen control via the Di2 hood buttons from Shimano Di2 drivetrains. 

Important note: all other Karoo 2 functionality will continue to work for Shimano riders, it is this small subset of Di2 features that Shimano has withdrawn permissions for until we are able to forge a new agreement.

We remain hopeful in pursuit of a new path to provide more software features to Shimano riders in the years ahead. For any questions or concerns, please reach out to us at


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