Stihl .325" 7 Tooth Rim Sprocket Kit - MS260, MS270, 026

Restore ultimate cutting torque, extend guide bar service life, and upgrade your mid-range chainsaw drive line with the Genuine OEM STIHL 0.325" 7-Tooth Rim Sprocket System Kit. Manufactured under factory part number 1121 007 1037 (1121-007-1037), this complete clutch drum and drive rim assembly converts fixed spur sprocket setups into a professional floating rim system. By allowing the saw chain to float laterally on a splined hub, the chain automatically aligns itself perfectly with the groove of your guide bar—reducing side-rail friction, preventing drive link burring, and delivering smooth, efficient power transfer from your engine's clutch.

Featuring the standard factory-recommended 7-tooth (7T) gearing in .325" pitch, this kit delivers the optimal balance of engine torque and chain speed, making it the ideal setup for heavy firewood bucking, felling, and general woodcutting in dense hardwoods. Built from case-hardened, high-density steel alloys, the replaceable floating rim design makes long-term maintenance simple and affordable: when the drive rim shows wear, simply pop off the retaining clip and slide on a fresh rim ring—no need to purchase a complete new clutch drum assembly.

True Genuine OEM Precision vs. Cheap Aftermarket Assemblies: Chainsaw drive line components take the full mechanical brunt of your powerhead's torque. Inferior aftermarket clutch drums often suffer from out-of-round machining, loose spline tolerances, and soft metal teeth that wear down after minimal use, leading to severe vibration and clutch slippage. Genuine STIHL drive kits guarantee precise clutch drum depth, exact needle bearing seating, and hardened splines engineered to handle daily commercial forestry use.

Configuration & Fitment Profile: Precision engineered for STIHL mid-chassis saw platforms running .325" pitch guide bars and chains. Directly compatible with the clutch and drive systems of the iconic 026, 026 Pro, MS 260, MS 260 Pro, as well as the oil pump and clutch drives of the MS 270, MS 270 C-B, and MS 280 series.

Key Features & Benefits

• Optimal 7-Tooth (7T) Factory Gearing: Delivers maximum pulling torque and engine RPM stability in tough hardwoods, heavy bucking, and felling operations.
• Self-Aligning Floating Rim Mechanism: The replaceable rim floats freely on the splined hub, allowing the cutting chain to automatically line up with the bar groove to reduce friction and bar rail wear.
• 100% Genuine OEM STIHL Construction: Formulated from heat-treated, high-grade steel alloys to resist premature tooth grooving under heavy thermal and physical loads.
• Cost-Effective Replaceable Rim System: Saves money over the life of your saw—simply swap the inexpensive rim ring when service intervals require it rather than replacing the whole drum.
• Seamless Oil Pump Interface: Features precision drive notch geometry that engages smoothly with the oiler drive wire on adjustable and automatic oil pump models.

Technical Specifications & Master Fitment Chart