Stihl MS 661 R chain size

Chainsaw drawing: the bar and chain are the parts this page is about

The chain for your Stihl MS 661 R

Which bar is on your saw?

Which chain is on it now?

20" bar

Pitch: 3/8"
Gauge: .050"
Drive links: 72

20" bar

Pitch: 3/8"
Gauge: .063"
Drive links: 72

22" bar

Pitch: 3/8"
Gauge: .063"
Drive links: 76

25" bar

Pitch: 3/8"
Gauge: .050"
Drive links: 84

25" bar

Pitch: 3/8"
Gauge: .063"
Drive links: 84

28" bar

Pitch: 3/8"
Gauge: .050"
Drive links: 91

28" bar

Pitch: 3/8"
Gauge: .063"
Drive links: 91

30" bar

Pitch: 3/8"
Gauge: .063"
Drive links: 98

32" bar

Pitch: .404"
Gauge: .063"
Drive links: 95

32" bar

Pitch: 3/8"
Gauge: .050"
Drive links: 105

32" bar

Pitch: 3/8"
Gauge: .063"
Drive links: 105

36" bar

Pitch: .404"
Gauge: .063"
Drive links: 105

36" bar

Pitch: 3/8"
Gauge: .050"
Drive links: 114

36" bar

Pitch: 3/8"
Gauge: .063"
Drive links: 114

Buy this chain

3/8 pitch, .050 gauge, 72 drive links

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Check pitch, gauge and drive links on the listing before you order. How this works

All bar lengths for the Stihl MS 661 R

Chain for each bar length
Bar	Pitch	Gauge	Drive links
20"	3/8"	.050"	72
20"	3/8"	.063"	72
22"	3/8"	.063"	76
25"	3/8"	.050"	84
25"	3/8"	.063"	84
28"	3/8"	.050"	91
28"	3/8"	.063"	91
30"	3/8"	.063"	98
32"	.404"	.063"	95
32"	3/8"	.050"	105
32"	3/8"	.063"	105
36"	.404"	.063"	105
36"	3/8"	.050"	114
36"	3/8"	.063"	114

The Stihl MS 661 R chain depends on the bar. 20" bar: 3/8", .050", 72 drive links; 20" bar: 3/8", .063", 72 drive links; 22" bar: 3/8", .063", 76 drive links; 25" bar: 3/8", .050", 84 drive links; 25" bar: 3/8", .063", 84 drive links; 28" bar: 3/8", .050", 91 drive links; 28" bar: 3/8", .063", 91 drive links; 30" bar: 3/8", .063", 98 drive links; 32" bar: .404", .063", 95 drive links; 32" bar: 3/8", .050", 105 drive links; 32" bar: 3/8", .063", 105 drive links; 36" bar: .404", .063", 105 drive links; 36" bar: 3/8", .050", 114 drive links; 36" bar: 3/8", .063", 114 drive links.

Stihl genuine part numbers

If you prefer the maker's own parts, these are the numbers to ask for at a dealer.

Stihl bar and chain part numbers
Bar	Chain part no.	Bar part no.	Pitch / gauge	Drive links
20"	33 RS3 72	3003 008 8921	3/8" / .050"	72
20"	36 RS3 72	3003 008 6121	3/8" / .063"	72
22"	36 RS3 76	3003 000 9425*	3/8" / .063"	76
25"	33 RS3 84	3003 000 4030	3/8" / .050"	84
25"	36 RS3 84	3003 000 5231*	3/8" / .063"	84
28"	33 RS3 91	3003 000 8838*	3/8" / .050"	91
28"	36 RS3 91	3003 000 6038*	3/8" / .063"	91
30"	36 RS3 98	3003 000 6041*	3/8" / .063"	98
32"	46 RS 95**	3003 000 7346*	.404" / .063"	95
32"	33 RS3 105	3003 000 8846*	3/8" / .050"	105
32"	36 RS3 105	3003 000 6046*	3/8" / .063"	105
36"	46 RS 104**	3003 000 7353*	.404" / .063"	105
36"	33 RS3 114	3003 000 8853*	3/8" / .050"	114
36"	36 RS3 114	3003 000 6053*	3/8" / .063"	114

Check the chain on your saw

Drawing: pitch is the distance between three rivets divided by two — **Pitch** Measure across three rivets and divide by two. Common pitches are 1/4", .325", 3/8" and .404".

Drawing: gauge is the thickness of the drive link in the bar groove — **Gauge** The thickness of the drive link that rides in the bar groove: .043", .050", .058" or .063".

Drawing: count the drive links, the tabs under the chain — **Drive links** Lay the chain flat and count the tabs underneath. Mark one with a paint pen so you know where you started.

Find pitch and gauge from the number on a drive link

Stamp number

Type the number on a drive link

See all stamp numbers

Drive link stamp number to pitch and gauge
Stamp	Pitch	Gauge
11	3/4"	.122"
16	.404"	.063"
18	.404"	.080"
20	.325"	.050"
21	.325"	.058"
22	.325"	.063"
25	1/4"	.050"
26	.404"	.058"
27	.404"	.063"
33	.325"	.050"
34	.325"	.058"
35	.325"	.063"
50	.404"	.050"
51	.404"	.058"
52	.404"	.063"
58	.404"	.058"
59	.404"	.063"
68	.404"	.063"
72	3/8"	.050"
73	3/8"	.058"
75	3/8"	.063"
80	.325" LP	.043"
90	3/8" LP	.043"
91	3/8" LP	.050"
95	.325"	.050"

Questions people ask

What size chain does a Stihl MS 661 R take?

How many drive links is a Stihl MS 661 R chain?

It depends on the bar: 72 on a 20" bar, 72 on a 20" bar, 76 on a 22" bar, 84 on a 25" bar, 84 on a 25" bar, 91 on a 28" bar, 91 on a 28" bar, 98 on a 30" bar, 95 on a 32" bar, 105 on a 32" bar, 105 on a 32" bar, 105 on a 36" bar, 114 on a 36" bar, 114 on a 36" bar. The bar length is usually printed near the mount.

Can I use a chain with the same length but different pitch?

No. Pitch and gauge have to match the bar and sprocket, and the drive link count has to match the bar. A chain that is off on any of the three will not fit or run safely.

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