Chain Size Calculator: Identify Any Roller Chain
Measure pitch, inner width and roller diameter with calipers and get the closest standard chain, such as 520, 428, #40 or 08B.
Enter Your Measurements
1. How did you measure the pitch?
Best match · score 100 of 100
520: 520 Motorcycle (MX / Sportbike Conversion)
Used on: 250cc–450cc MX/Enduro, 600cc–1000cc track conversions
Pitch
15.875mm
Off by:0 mm
Inner Width
6.35mm
Off by:0 mm
Roller Ø
10.16mm
Off by:0 mm
Avg. Tensile
8,161lbf
Metric:36,300 N
Data:manufacturer
Chain link measurement guide
Closest standards
| Chain | Pitch | Inner width | Roller Ø | Score | Actions |
|---|---|---|---|---|---|
| 520520 Motorcycle (MX / Sportbike Conversion) | 15.875 mm | 6.35 mm | 10.16 mm | 100 | |
| 525525 Street / Sportbike OEM | 15.875 mm | 7.94 mm | 10.16 mm | 81 | |
| 530530 Heavy Duty Sport / Cruiser | 15.875 mm | 9.525 mm | 10.16 mm | 62 | |
| #50ANSI #50 Standard Roller Chain (5/8" Pitch) | 15.875 mm | 9.525 mm | 10.16 mm | 62 | |
| 10BISO 10B Metric Roller Chain (5/8" Pitch) | 15.875 mm | 9.65 mm | 10.16 mm | 60 |
How to Measure a Roller Chain
Use a vernier or digital caliper on a clean, straight section of chain. Take each reading more than once. Once you know the size, work out how many links you need with the chain length calculator, or, for a derailleur bike, the bike chain length calculator.
1. Pitch
2. Inner width
3. Roller diameter
Roller Chain Size Reference
Values come from the same chain database the calculators use. For wear limits per chain, see the chain wear and stretch calculator.
| Chain | Type | Pitch (mm) | Pitch (in) | Roller Ø (mm) | Inner Width (mm) | Tensile Strength | Wear Limit |
|---|---|---|---|---|---|---|---|
| 415 | Motorcycle | 12.700 | 0.5000 | 7.75 | 4.76 | 16,500 N (3,710 lbf) avg. ≈ | 1.50% |
| 420 | Motorcycle | 12.700 | 0.5000 | 7.77 | 6.35 | 19,600 N (4,406 lbf) avg. | 1.50% |
| 428 | Motorcycle | 12.700 | 0.5000 | 8.51 | 7.75 | 24,500 N (5,508 lbf) avg. | 1.20% |
| 520 | Motorcycle | 15.875 | 0.6250 | 10.16 | 6.35 | 36,300 N (8,161 lbf) avg. | 1.00% |
| 525 | Motorcycle | 15.875 | 0.6250 | 10.16 | 7.94 | 41,200 N (9,262 lbf) avg. | 1.00% |
| 530 | Motorcycle | 15.875 | 0.6250 | 10.16 | 9.53 | 41,200 N (9,262 lbf) avg. | 1.00% |
| 630 | Motorcycle | 19.050 | 0.7500 | 11.91 | 9.53 | 44,126 N (9,920 lbf) avg. ≈ | 1.00% |
| #35 | ANSI | 9.525 | 0.3750 | 5.08 | 4.76 | 7,829 N (1,760 lbf) min. | 1.50% |
| #40 | ANSI | 12.700 | 0.5000 | 7.92 | 7.92 | 13,901 N (3,125 lbf) min. | 1.50% |
| #50 | ANSI | 15.875 | 0.6250 | 10.16 | 9.53 | 21,707 N (4,880 lbf) min. | 1.50% |
| 08B | ISO | 12.700 | 0.5000 | 8.51 | 7.75 | 17,802 N (4,002 lbf) min. | 1.50% |
| 11/128" (9–12 Spd) | Bicycle | 12.700 | 0.5000 | 7.75 | 2.18 | 9,200 N (2,070 lbf) avg. ≈ | 0.50% |
Tensile strength is the maker's minimum for ANSI and ISO chain and the average for motorcycle chain. ≈ marks values without a manufacturer table.