Reference
ANSI Roller Chain Size Chart
Standard ANSI (ASME B29.1) roller chain dimensions from #25 through #200. Use this chart to identify a chain from the shape of a link, or to spec a replacement. All values are for single-strand construction; double- and triple-strand ratings scale with the number of strands.
| Size | Pitch (in / mm) | Roller Ø (in / mm) | Inside width (in / mm) | Avg tensile (lbf) |
|---|---|---|---|---|
| #25 | 0.250 / 6.35 | 0.130 / 3.30 | 0.125 / 3.17 | 925 |
| #35 | 0.375 / 9.52 | 0.200 / 5.08 | 0.188 / 4.78 | 2,100 |
| #40 | 0.500 / 12.70 | 0.313 / 7.94 | 0.313 / 7.94 | 3,700 |
| #41 | 0.500 / 12.70 | 0.306 / 7.77 | 0.250 / 6.35 | 2,000 |
| #50 | 0.625 / 15.88 | 0.400 / 10.16 | 0.375 / 9.52 | 6,100 |
| #60 | 0.750 / 19.05 | 0.469 / 11.91 | 0.500 / 12.70 | 8,500 |
| #80 | 1.000 / 25.40 | 0.625 / 15.88 | 0.625 / 15.88 | 14,500 |
| #100 | 1.250 / 31.75 | 0.750 / 19.05 | 0.750 / 19.05 | 24,000 |
| #120 | 1.500 / 38.10 | 0.875 / 22.22 | 1.000 / 25.40 | 34,000 |
| #140 | 1.750 / 44.45 | 1.000 / 25.40 | 1.000 / 25.40 | 46,000 |
| #160 | 2.000 / 50.80 | 1.125 / 28.57 | 1.250 / 31.75 | 58,000 |
| #200 | 2.500 / 63.50 | 1.563 / 39.69 | 1.500 / 38.10 | 95,000 |
How to identify roller chain
The chain size number is chain pitch × 8, in eighths of an inch. #40 has a 40/8 = 5-eighths inch — wait, that's a 1/2-inch pitch (40/80 of an inch). The rule: divide the number by 80 to get the pitch in inches. #60 = 0.75" pitch, #80 = 1" pitch, #100 = 1.25" pitch.
The suffix matters. #40-1 is single-strand, #40-2 is double-strand (double the load capacity), #40-3 is triple-strand. An H suffix (#80H) is heavy-series — same pitch but thicker side plates for higher fatigue life. #41 is a narrow-width variant of #40 for light-duty applications.