If your roller chain is worn out, damaged, or has broken, you don't necessarily need the original part number to order a replacement.
In most cases, identifying a roller chain comes down to three simple measurements:
- Chain pitch
- Roller diameter
- Inner width
Once you have these measurements, RR Fisher can help match the correct replacement chain with our range that you can find here.
Step 1: Check for a Chain Number
Before reaching for a tape measure, inspect the side plates of the chain.
Many roller chains have the chain size stamped into the outer plates, such as:
- 40
- 50
- 60
- 80
- 08B
- 10B
- 12B
- 16B
If you can find the chain number, identification is usually straightforward. Clean off any dirt, grease, or rust and check several links along the chain.
Step 2: Measure the Chain Pitch
The most important measurement is the chain pitch.
Chain pitch is the distance from the centre of one pin to the centre of the next. The easiest way to measure it is to measure from the centre of the first pin to the centre of the third pin and divide the result by two.
Common chain pitches include:
|
Pitch |
ANSI Size |
BS Size |
|
3/8" (9.525mm) |
35 |
06B |
|
1/2" (12.7mm) |
40 |
08B |
|
5/8" (15.875mm) |
50 |
10B |
|
3/4" (19.05mm) |
60 |
12B |
|
1" (25.4mm) |
80 |
16B |
Step 3: Measure the Roller Diameter
The roller diameter is the outside diameter of the round roller between the side plates.
Use vernier calipers for the most accurate measurement.
This measurement helps distinguish between chains that may have a similar pitch but belong to different chain standards.
Step 4: Measure the Inner Width
The inner width is the distance between the inner side plates.
Using calipers, measure the gap between the plates where the sprocket tooth runs.
Combined with the pitch and roller diameter, this measurement is usually enough to positively identify the chain.
ANSI or British Standard Chain?
In New Zealand, you'll commonly find both:
- ANSI chain (40, 50, 60, 80, etc.)
- British Standard chain (08B, 10B, 12B, 16B, etc.)
Although some sizes look similar, they are not always interchangeable and may not fit the sprocket correctly.
Found Your Chain Size?
Once you've identified your chain size, head to our online chain range and use the filters to narrow down your options. We have both British Standard chain and the ANSI chain as well as a large range of chain tools and chain tensioners.
Filter by:
- Chain size (08B, 10B, 12B, 40, 50, 60, etc.)
- Simplex, duplex or triplex
- Roller chain, connecting link or offset link
- Standard, stainless steel or heavy-duty chain
This makes it quick and easy to find the exact replacement chain or connecting link you need. Any trouble give us a call on 0800 235 877 or contact us via the webform.