I run both a 24" bar and a 36" bar on my 064, but I run skip-tooth chain on the 36" bar, and switch over to the shorter bar whenever practical. yuou could get away with a bigger bar, but it would be hard on the saw, as well as slow cutting.
The Stihl 032 was introduced in 1978 and the maxrecamended bar length is 20". But I know from experiencethey can easilyhandle up to 24".
You can use several length bars on this saw. It looks like it came from the factory with a 20" bar.
Can I put a 18inch bar on a stihl
An 042AVE is 68cc and generally will run a 16", 18" or 20" bar. They use a 3/8" full profile chain that has 60, 66 or 72 drive links respectively depending on bar length.
The Stihl chainsaw model 08S has 3.75 horsepower or 2.8 kW. The displacement is 60.3 cc, the length of the bar is 24.8 inches, and the weight is 15.9 pounds.
20 in. Bar
A STIHL 045 av is 75cc and the max recommended bar size for it is 32". However... If you have a 045 av Super then it would be 87cc and the max recommended bar length would be 36". So it depends if you have a SUPER or not. It is easy to tell as it will say SUPER on the top tag right below 045 av.
The Stihl 023 is 40.1cc - 2.45cu.in. -weight 10.1 lbs. w/o bar and chain
Some Stihl chain saws have an adjuster underneeth the saw to turn up the oiler .
An 18" or 20" bar would be ideal on a Stihl 041 http://store.chainsawr.com/
20 inch bar and chain
For a 20" Bar 325 Pitch .063 Gauge Chain 81 Links