Industrial V-belt Cross Reference for 4L and 5L Belts
Dayco experts suggest switching from a 4L or 5L V-belt for some industrial/HVAC applications to a GOLD LABEL raw edge (notched) belt for increased performance and longevity. Here is how to cross reference these belts using the part numbers:
- 4L = AX section
- 5L = BX section
The remainder of the part number gives you the OUTSIDE circumference divided by 10.
AX and BX section part numbers are given by the INSIDE circumference.
- AX part number + 2 = outside circumference
- BX part number + 3 = outside circumference
Example:
- 4L440 = AX42 (4L = A; 440 = 44″ OC; 44 – 2 = 42 IC thus AX42 – *X for notched belt*)
- 5L550 = BX52 (5L = B; 550 = 55″ OC; 55-3=52 IC thus BX52)
Our team does not recommend replacing a 4L belt with an A section wrapped belt due to the difference in the minimum pulley diameters (see chart below). Going from 4L to an A section or from 5L to a B section is risky due to minimum pulley diameters. A BX can survive on a 3.5″ pulley and given the much higher capacity and temperature range, compensates for reduced life due to smaller than recommended pulley diameter condition.
