OS-FR Series Sequential Gearbox

The OS-FR5 and OS-FR7 Sequential Transmissions are specifically designed for use in JDM sport-compact and roadster vehicles.

The “FR” of OS-FR series name designates the front-engine, rear-wheel-drive vehicle specific application for this transmission series. OS-FR series Sequential Transmissions are designed with tear-drop shaped transmission housing and top-mounted gear selector to allow ease of fitment in limited transmission tunnel space often found in compact FR vehicles. A few examples of vehicles suited for the OS-FR series transmission are Mazda MX-5 (NA/NB), Mazda RX7 (FD), or Honda S2000.

OS-FR5

The OS-FR5 is a 5-speed iteration of OS-FR series Sequential Transmission that is designed to handle high torque and power output, while remaining within the spatial constraints of compact FR vehicles. Developed through vigorous testing, the dog-ring and gear design of FR5 allows relatively low shifting efforts for its torque capacity. Manufactured with carefully selected raw-forged materials, the OS-FR5 can handle up to 575 ft/lbs of torque.

OS-FR7

The OS-FR7 is Japan’s very first 7-speed sequential transmission. Contrary to common designs where there is a direct-drive gear within the transmission, the FR7 does not have a direct-drive gear due to a unique drop-gear design. The drop-gear design minimizes shifting effort and allows quick and precise shifting. Along with the ease of shifting, the spread of 7 gears in FR7 allows the vehicle to easily stay in power band regardless of the engine characteristics. Manufactured with carefully selected raw-forged materials, the OS-FR7 can handle up to 430 ft/lbs of torque.

FR5 & FR7 Gear Ratios