SRAM HammerSchmidt Crankset

The HammerSchmidt is a dual-speed, crank-mounted transmission shifting system that offers a direct drive 1:1 gear ratio coupled to an overdrive gear, which changes the ratio to 1:1.6 through a sealed planetary gear system. This innovative new shifter design was based on a new product concept developed by the advanced development team at SRAM. Design Integrity’s team of mechanical design consultants was brought onto the program to assist with the engineering development effort from concept through production.

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During downhill racing and mountain bike riding, cyclists often have trouble finding the correct gearing fast enough to maintain momentum and drive.  Even bikes with a single front chain ring and a rapid shifting rear derailleur can take too long to find the right gear when multiple shifts are needed.  In addition, cyclists have had to back off on pedal pressure when shifting as traditional shifters do not work well under full load.


SRAM partnered with DI to develop the Truvativ HammerSchmidt crankset.  This innovative, new front hub shifts instantaneously under full load or no load, whether at full speed or at a standstill.  The system was designed with a planetary gear mechanism that can be shifted from direct drive (1 to 1 gear ratio) to overdrive (1.6 to 1 gear ratio).  The shifting is triggered by a switch on the handlebars, and it allows riders to change from a low gear to a high gear, or vice versa, in an instant.

Client Benefit

The DI team collaborated with SRAM from the initial engineering design phase through prototyping, engineering testing, tooling development, and production launch.  The Truvativ HammerSchmidt Crankset went to market and received strong reviews from magazines and riders, allowing SRAM to continue a tradition of innovation and reliable new bike products that improve the riding experience for cyclists.

“Out on the trail . . . we were continuously surprised by the quickness of the HammerSchmidt shifts, both up and down. With a traditional system, upshifts to larger chainrings usually happen pretty slowly by comparison. Once we became used to it, we were able to shift at will, under any power load, anytime we wanted. Imagine riding a new trail and bombing down a hill at speed only to find a sharp blind corner with a steep short climb directly after. This situation is tailor-made for the HammerSchmidt …  With a traditional front derailleur system, you’d need to soft pedal for a bit to get the downshift.”

Competitive Cyclist

December 2008 Review

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