Selecting the correct chain for your Stihl MS 170 is fundamental to ensuring optimal performance, safety, and longevity of your equipment. While the MS 170 is a popular and reliable chainsaw, using the wrong chain can lead to inefficient cutting, excessive vibration, and even premature wear on the bar and sprocket. This guide breaks down everything you need to know about the proper chain size and how to identify the correct one for your specific model.
Understanding Chain Specifications for the MS 170
The Stihl MS 170 is designed to work with a specific chain configuration that balances cutting efficiency and user safety. The primary specification you need to look for is the drive link pitch and gauge, which determine the physical fit within the bar nose and the engine's gearing. For the vast majority of standard Stihl MS 170 models, the required chain size is a .325-inch pitch with a .050-inch gauge.
Identifying Your Exact Model
Before purchasing a replacement chain, you must verify your specific saw's model number. While the .325-inch pitch is standard for the MS 170, Stihl has produced various versions over the years, and checking the identification tag is the only way to be 100% certain. You can usually find this tag on the rear handle of the saw, near the bar mount. Look for a format such as "MS 170" or "MS 170 C-M" to confirm you are looking at the correct platform.
Specifications at a Glance
To save you time, here is a quick reference table outlining the most common chain measurements for the standard Stihl MS 170 chainsaw:
| Specification | Measurement | Notes |
|---|---|---|
| Drive Link Pitch | .325 inches | The distance between drive links; must match the sprocket. |
| Gauge (Thickness) | .050 inches | The thickness of the drive links; must fit the bar groove tightly. |
| Standard Chain Length | 12", 14", 16", 18", 20", 24", 30", 36", 40" | Measured in drive links; choose based on bar length. |
Matching Chain Length to Bar Length
The pitch and gauge ensure the chain fits mechanically, but the length determines performance. The chain length is measured by the number of drive links, not total inches. To find the right size, you need to know the length of your bar. Most MS 170 models come with a bar length between 10 to 16 inches, which translates to roughly 30 to 35 drive links.
- 10-inch to 12-inch bars: Typically use a chain with 30 to 35 links.
- 14-inch to 16-inch bars: Typically use a chain with 36 to 42 links.
Always refer to the groove in the center of the bar; the chain must fit snugly without gaps. Using a chain that is too long for the bar can cause binding and kickback, while a chain that is too short will not engage the clutch properly.
Installation and Tuning Tips
Once you have identified the correct Stihl MS 170 chain size, proper installation is the next critical step. Always ensure the saw is turned off and the spark plug wire is disconnected before changing the chain. As you tighten the bar nut, the chain must be properly tensioned.
- The chain should be tight enough that it does not sag away from the bar.
- You should be able to lift the chain slightly off the bottom of the bar groove with your thumb.
- After tightening, start the saw and let it run for a minute; check the tension again once the chain has warmed up and stretched slightly.
Specialty Chains and Upgrades
While the standard .325-inch pitch works perfectly for general cutting, some users may require specialty chains for specific tasks. If you are performing landscaping work or cutting softwood, you might explore chains with different configurations, such as those optimized for clean cuts or reduced kickback.
Regardless of the specialty, the physical dimensions usually remain the same (.325 pitch, .050 gauge) to ensure compatibility with the MS 170's sprocket and bar. Always verify compatibility with your saw's manual before fitting a non-OEM (Original Equipment Manufacturer) chain to ensure the drive links align with the clutch drum.