There are actually 4 sizes of hook type fork carriages rated by the blade carriage lifting capacity. Hook type tine carriages have been the same.
The carriage bar spacing used for Class 1 is something like 13 inches and the Class 1 carriage is rated to hold loads up to 2000lbs. The Class 2 carriage is rated to carry cargo up to 5,500lbs with carriage bar spacing of 16 inches. Class III carriages are rated for cargo up to 10,000 lbs. The carriage bar spacing for this class is 20 inches. Class IV carriages are rated for loads up to 15,500 lbs. The carriage bar spacing utilized for this capacity is twenty five inches.
Pin mounted forks vary by the amount of offset between the blade and the tine eye. Some makers will vary the carriages for pin type tines. Carriage capacity would be determined by the carriage pin size and by the fork size.
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