| Size | Pitch | Inner width | Roller Ø | Typical use |
|---|---|---|---|---|
| 25 | 1/4" 6.35 mm | 1/8" 3.17 mm | 0.13" 3.30 mm | Electric scooters, pocket bikes |
| 35 | 3/8" 9.52 mm | 3/16" 4.76 mm | 0.2" 5.08 mm | Minibikes and go-karts (torque converter or clutch) |
| 41 | 1/2" 12.70 mm | 1/4" 6.35 mm | 0.306" 7.77 mm | Light-duty minibikes and karts |
| 40 | 1/2" 12.70 mm | 5/16" 7.94 mm | 0.312" 7.92 mm | Go-karts and minibikes with bigger engines |
| 415 | 1/2" 12.70 mm | 3/16" 4.76 mm | 0.306" 7.77 mm | Some 50cc race bikes and motorized bicycles |
| 420 | 1/2" 12.70 mm | 1/4" 6.35 mm | 0.306" 7.77 mm | 50–110cc pit bikes, kids’ dirt bikes, small ATVs |
| 428 | 1/2" 12.70 mm | 5/16" 7.94 mm | 0.335" 8.51 mm | 110–250cc pit bikes, dirt bikes and ATVs |
| 520 | 5/8" 15.88 mm | 1/4" 6.35 mm | 0.4" 10.16 mm | 250cc+ dirt bikes, most sport ATVs |
| 525 | 5/8" 15.88 mm | 5/16" 7.94 mm | 0.4" 10.16 mm | Mid-size and large road bikes |
| 530 | 5/8" 15.88 mm | 3/8" 9.52 mm | 0.4" 10.16 mm | Large and older road bikes |
How to read a chain number
For motorcycle chains (420, 428, 520…) the first digit is the pitch in eighths of an inch: 4 = 4/8 = ½", 5 = ⅝". The last two digits indicate the width: 20 is ¼", 28 and 25 are 5/16", 30 is ⅜".
ANSI chains used on karts and minibikes work the same way for pitch: #35 = 3/8", #40 and #41 = ½". #41 is a lighter, narrower version of #40.
Which chains fit the same sprocket?
A sprocket must match both pitch and width. Same pitch with a narrower chain (420 on a 428 sprocket) usually rides badly and wears fast; a wider chain won’t fit on a narrower sprocket. Different pitches never mix – a 428 chain will not run on a 520 sprocket.
Dimensions are nominal values from the ANSI roller-chain standard and common motorcycle chain specifications. Individual brands vary slightly – check your chain maker’s catalog for exact figures such as plate thickness and tensile strength.