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Chains are produced in a range of standard pitch sizes and sprockets are limited to a preferred range of numbers of teeth. Traditionally, industrial series chains are produced in imperial sizes with metric conversions and this remains the situation.

Pitch Sizes

Standard chain pitches are as follows

Mini Pitch Chain         4 mm        5mm        6 mm        8 mm

Industrial Series        1/4 " (6.35 mm)        3/8 " (9.525 mm)      1/2 " (12.70 mm)

5/8 " (15.875 mm)     3/4 " (19.05 mm)      1 " (25.4 mm)           1 1/4 " (31.75 mm)

1 1/2 " (38.10 mm)    1 3/4 " (44.45 mm)    2 " (50.8 mm)          2 1/2 " (63.5 mm)

Standard Sprocket Teeth Numbers

The ISO Recommendation gives a preferred range for the numbers of teeth as follows:

       17      19      21      23      25      38       57      76      95      114

However, the range carried by leading manufacturers is usually much larger because having a wider range of sprockets often enables target reduction ratios to be more accurately achieved. In the Renold Chain catalogue the following sprocket teeth numbers are available and this range is typical of leading manufacturers :

     11     12     13     14     15     16     17     18     19     20    21     22     23

     24     25     26     27     30     35     38     40     57     76    95     114

Operating Recommendations

Generally sprocket teeth numbers should be:

• not be less than 15 teeth using large pitch chain when operating at speeds greater than 100 R.P.W
  
  
• not less than 17 teeth when using small pitch chain at speeds above 100 R. P. M. ;
  
  
• at least 19 teeth are recommended for normal applications with medium to high speeds ;
  
  
• 23 or more teeth are necessary for impulse applications.