In 2020, Stihl will release a new saw chain with a .325” pitch and a 1.3 mm gauge. The name is Stihl RS or RM, with the extension PRO after. The two versions, RM and RS, stand for Rapid Micro and Rapid Super where micro is Semi-Chisel and super is Full-Chisel.

Stihl will also release an RM3 PRO chain with reduce jolting tendencies and low vibrations, which usually entails a small reduction to capacity. None of this is new, Stihl has operated like this before and chains with “3” at the end are offered to customers who may not desire optimal cutting ability over a relatively non-aggressive chain that is easy to use and without surprises.

The PRO chain in a new system

The new chain based on a 0.325” pitch is part of a new cutting system from Stihl. The other part is the new sword, which Stihl has dubbed Light04.

Though it’s not really new (Stihl has had a .325” chain with a 1.3 mm gauge before), the new chain is exciting and there is much to discuss. Clearly, the PRO chain (especially the RM version) is a direct contender to the Husqvarna SP33g X-cut and the Oregon SpeedCut 95TXL, as they are all .325 with a 1.3 mm gauge.

Stihl claim that the new PRO chain is newly developed from scratch and is primarily intended for use with the 50cc MS 261 and MS 271 saws, but is generally recommended for chainsaws with power levels of between 2.2 and 3.0 kW. Like its competitors, the chain should be filed with a 4.8 mm round file, which is different from the Picco ⅜ which should be filed with 4.0 mm round file.

In Stihl’s own tests, the new PRO chain is 20% more efficient at cutting of upper directional cuts and up to 15% more efficient on ordinary cutting, compared to the previous RS .325.

The new cutting system (Light04 with PRO chain) will be available in 4 different lengths, whereof three in the Nordic countries. There’s 14”, 16” and 18” with 60, 67 and 74 drive links on the chain. There will also be a 20” option. Stihl already has 13” and 15” options, but they are now being phased out in favor of 14” in length. Spare parts for the 13” and 15” systems will be available until 2024.

It’s unclear if Stihl will be offering complete PRO chains with other numbers than the above in the future. All PRO chains will be pre-stretched in factory to reduce the tension of the new chain.

Reduced cutting width

With the PRO chains, the actual cutting width, i.e. the track that is left after you cut, will decrease compared to the older chain. Stihl states that PRO will have a cutting width of 6.8 mm. It’s somewhat unclear at this point how this compares to for example the SP33g and 95TXL, but data is available for Stihl’s alternative Picco ⅜, which shows a width of 6.7 mm. Stihl isn’t able to (or does not want to) achieve a smaller cutting width than its Picco chain, but it’s very close and compared to the older chain there is a big difference as it has a cutting width of 7.7 mm, according to Stihl. During the shorter tests we have done with the chain ourselves, the cutting width seems to be very good. We will return with more detailed tests between different types of chains to look at the differences. It’s a very interesting aspect; if you can reduce the cutting width you can reduce the energy consumption, which saves both power and fuel. 

A first test of the RS / RM PRO

Forestry has been granted the opportunity to test an MS 261 with the new Light04 and the PRO chains. We haven’t done any in-depth testing yet, but despite this the PRO chains are a pleasant experience. As you may predict, RS is a little more aggressive and cuts slightly better than RM. The same is true for branching. The RS is aggressive and is happy to take command of its own, which can easily result in accidentally cutting the trunk. No big deal, it’s a full-chisel chain that is optimized for fast work. RM in turn is really nice for both cutting and removing twigs. It has no tendencies to take over and all steps are performed without surprises. Both have high cutting capacities and compare reasonably with the Picco ⅜ from Stihl, which the PRO chain seems to be in par with.

Spontaneously and initially, the system feels very good indeed. Stihl has a sword that is light, narrow but still stable and stiff, and the PRO chains are a pleasant experience. It will be very interesting to test this system further and discuss it with users when it reaches the market, which it’s expected to do by the end of February 2020.