Stihl .3/8" 7 Tooth Rim Sprocket Kit - MS260, MS270, 026

Convert your mid-range STIHL chainsaw to run a standard full-size 3/8" cutting system—or restore your existing setup to factory fresh performance—with the Genuine OEM STIHL 3/8" 7-Tooth Rim Sprocket System Kit. Precision-manufactured under factory part number 1121 007 1041 (1121-007-1041), this complete clutch drum and drive rim assembly is engineered specifically for saws equipped with adjustable oilers. Upgrading from a fixed-spur sprocket to a floating rim system allows your 3/8" cutting chain to self-align dynamically with the guide bar groove, significantly reducing side-load wear, preventing drive link burring, and delivering maximum engine power directly to the cut.

Featuring a standard small-spline hub loaded with a 7-tooth (7T) 3/8" pitch rim, this kit provides the ideal gearing balance for mid-displacement powerheads, maximizing chain torque while cutting through tough hardwoods. Constructed from high-density, case-hardened steel alloys, the replaceable floating rim design makes long-term maintenance fast and affordable: when the drive rim shows tooth wear, simply pop off the retaining clip and replace the inexpensive rim ring rather than replacing the entire clutch drum assembly.

True Genuine OEM Quality vs. Low-Grade Aftermarket Drums: Chainsaw drive systems endure tremendous centrifugal stress, chain slap, and heat during heavy bucking. Inferior aftermarket clutch drums often feature unevenly machined spur teeth or loose spline tolerances, leading to severe vibration, chain binding, and premature clutch wear. Genuine STIHL drive components guarantee precise clutch drum depth, exact needle bearing fitment, and hardened splines engineered to handle commercial forestry use.

Configuration & Fitment Profile: Designed specifically for STIHL mid-range saw platforms configured with adjustable oil pumps running 3/8" pitch guide bars and chains. Directly compatible with the clutch and drive assemblies of the iconic 026, 026 Pro, MS 260, MS 260 Pro, as well as the oil pump drive setups of the MS 270, MS 270 C-B, and MS 280 series.

Key Features & Benefits

• Full 3/8" Pitch System Conversion: Enables mid-sized STIHL powerheads to run heavy-duty 3/8" pitch guide bars and chains for serious wood-cutting performance.
• 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: Manufactured to exact factory tolerances using heat-treated structural steel to resist premature tooth grooving under heavy loads.
• Cost-Effective Replaceable Rim System: Eliminates the expense of replacing whole clutch drums—simply swap the worn 7T rim ring when service intervals require it.
• Engineered for Adjustable Oiler Models: Hub notch profile interacts seamlessly with the worm gear drive wire on adjustable oil pump models for continuous chain lubrication.

Technical Specifications & Master Fitment Chart