Circular/radius crowns are preferred over bevels with flats.
For belts up to 3″ wide:
Min. Crowning=1.6% of belt width (1″ belt=.016 crown)
Max. Crowning=2.5% of belt width (1″ belt=.025 crown)
For belts over 3″ wide:
Min. Crowning=0.5% of belt width (5″ belt=.026 crown)
Max. Crowning=1.6% of belt width (5″ belt=.080 crown)
Unless unusual tracking problems exist, minimum recommended crowning should be chosen, since ideal properties are developed through uniform belt to pulley contact. If an extreme crown is chosen for use with a stable belt, the full belt width will not be able to stretch and conform to the pulley crown, leaving the percentage of the belt width, not the pulley width. Crown choice is primarily affected by belt styles, installation tension and the degree of precision found in the machine drive alignment.
Additional considerations include specific drive details such as required torque or horsepower to be delivered, pulley diameters and drive speeds which must be known for proper belt selection and adequate belt sizing for the application.
Any adverse conditions which the belt may encounter, such as extreme temperatures, hostile chemical environments or severe abrasion should be considered as should other specific properties required, such as specific belt thickness, anti-static requirements or FDA approval.