Compute roller-chain ratio, speed and links.
| Item | Formula | Source / Standard |
|---|---|---|
| Chain drive ratio | i = z2 / z1 | GB/T 1243 roller chain and sprockets |
| Chordal pitch polygon side | pitch circle diameter d = p / sin(PI / z) | ISO 606 roller chain dimensions |
| Chain link count | Lp = 2ap + (z1 + z2)/2 + (z2 - z1)^2 / (4 PI^2 ap) | GB/T 1243 chain drive calculation |