The Worm 1/4” 8T is a genuine Stihl drive gear for compact professional chainsaws, designed to engage 1/4 inch (6.35 mm) pitch chain with eight teeth for smooth, reliable power transfer. Built for durability, this metal gear helps maintain correct chain speed and clean cutting performance under regular use. It is engineered for a precise fit on Stihl top-handle and lightweight models such as the MS201 and MS201C, ensuring proper alignment with the clutch and chain. As an OEM part, MPN 1129 640 7102, it restores performance when the original gear is worn, reducing chain slip, vibration, and premature wear to the bar and chain. Suitable for everyday maintenance or repair, it keeps your saw running efficiently and safely.

Key Features:
– Genuine Stihl OEM component for assured fit and reliability (MPN 1129 640 7102)
– 1/4 inch (6.35 mm) pitch, 8-tooth specification for accurate chain engagement
– Precision-machined gear for smooth drive and consistent chain tracking
– Durable metal construction for long service life in tough conditions
– Direct replacement part to simplify maintenance and reduce downtime
– Helps reduce chain slip and uneven wear on the bar and chain
– Stable performance supports accurate cuts on pruning and light felling tasks
– Compatible with a wide range of Stihl compact saws listed below

Typical Applications:
Used to replace a worn or damaged drive gear on Stihl chainsaws to restore smooth chain drive, correct chain speed, and clean cutting. Common during routine servicing, clutch overhauls, or when experiencing symptoms such as chain drag, chatter, or inconsistent cutting performance. Suitable for arborists, landscapers, grounds teams, and home users maintaining small to medium timber.

Also known as:
Drive gear, chain drive sprocket, spur gear, worm wheel, 1/4” 8T sprocket, gear component, replacement gear.

Fits Models:
020, 020T, MS192C, MS192T, MS192TC, MS200, MS200T, MS201, MS201C, MS201T, MS201TC

Alternate Part Numbers:
1129-640-7102, 11296407102

Product Specifications