Keep your mid-range chainsaw operating at peak efficiency with the STIHL 3/8" 7-Tooth Rim Sprocket (Small Hole). This genuine replacement part (0000 642 1231) is engineered specifically for STIHL’s "Small" splined clutch drums found on many of the most popular farm, ranch, and professional saws. By utilizing a rim-style system, the sprocket is allowed to float on the splined hub, ensuring the chain remains perfectly aligned with the guide bar groove to reduce friction and heat buildup.
This 7-tooth configuration is the ideal setup for saws like the MS 261 and MS 290, providing a consistent power transfer that balances high chain speed with the torque needed for felling and bucking. Because the rim is a separate component from the drum, it is a cost-effective maintenance solution—simply replace the worn rim rather than the entire clutch assembly to keep your drive system in top condition.
Fitment Tip: This is the "Small Hole" (Small Spline) version. It is the factory-standard replacement for the MS 260 through MS 390 series and their classic predecessors.
Key Features & Benefits
- Floating Rim Technology: Automatically aligns the chain with the bar for smoother cutting and reduced wear.
- Small Spline Design: Precision engineered for STIHL's mid-range professional and "Farm Boss" series clutch drums.
- Optimized Performance: 7-tooth design provides the perfect gear ratio for 3/8" pitch chains on 50cc to 60cc powerheads.
- Durable Steel Construction: High-strength alloy built to withstand the rigors of frequent agricultural and professional use.
- Genuine STIHL Part: Ensures exact tolerances and maintains your saw’s factory warranty and safety standards.
Technical Specifications & Fitment
| Manufacturer Part Number | 0000 642 1231 |
| Chain Pitch | 3/8" |
| Spline Size | Small (SM) |
| Tooth Count | 7-Tooth |
| Fits Professional Models | MS 240, MS 260, MS 261, MS 270, MS 280, MS 290, MS 291, MS 310, MS311, MS 390, MS391, MSA300 |
| Fits Classic Models | 024, 026, 028, 029, 039, 034, 036 |