Tensioning the Chain Correctly

How to tension the saw chain correctly

Regular tensioning of the saw chain improves the safety during use and reduces wear and damage to the chain. We therefore recommend that you check the chain tension and make any necessary corrections each time before you start work.

During work with the chain saw, the chain becomes warm and therefore expands slightly. During manufacture, STIHL saw chains are “stretched” slightly in the factory, and this prevents excessive thermal expansion. Nevertheless, for your own safety, you must still tension it manually from time to time.

Most STIHL chain saws have an easy-to-use chain tensioner on the side, with which the chain can be tensioned in a matter of minutes. This is how it is done:

1. With the engine turned off, first loosen the securing screws of the chain cover with a combination wrench. To tension the chain, it is sufficient to only loosen these screws. Then turn the tensioning screw with the screwdriver end of the combination wrench (see picture).

2. Now check whether the chain lies loosely on the bar. To prevent injuries, you should wear protective gloves when doing this. If the lower side of the chain hangs away from the bar (see picture), it is too loose and you must turn the tensioning screw further.

3. If the lower side of the chain does not hang away from the bar, but the chain can still be pulled away slightly, the tension is correct. You should also be able to lift the top side of the chain slightly (see picture). To prevent injuries from the sharp edges of the chain, you should wear protective gloves when doing this.

You can tension the chain quickly and easily with the Quick Chain Tensioning feature, with which many STIHL chain saws are equipped as standard. This is how you do it:

Loosen the chain sprocket cover above the wing nut. Turning the adjusting wheel above this anticlockwise reduces the chain tension; turning it clockwise increases the tension. When the chain sprocket cover is screwed down, the guide bar is automatically fixed in position.

When replacing the saw chain, you should first scrape all dirt and deposits from the groove of the guide bar, since these can cause the chain to jump out of the bar. There is also a risk that such deposits soak up the chain lubricant before it can reach the bottom side of the guide bar, which is subjected to large stresses.

This would result in overheating and excessive wear of the chain and the bar. You can remove these deposits with a small screwdriver or some other sharp object. Before making the first cut with a new chain, you should allow the chain to “run in” for a few seconds.

“Caution: Since the chain contracts slightly as it cools after use, your should never tension or replace the chain while it is hot. This can result in serious damage to the guide bar or to the crankshaft of the engine. It is advisable to slightly reduce the chain tension when you finish work, particularly in frosty weather.”

For advice and service, you can of course also talk to us.