Belt Drive Monthly
Volume 21• April 2010
Can I Interchange 4L And 5L V-Belts With
A or B V-Belts?
Browning fractional horsepower v-belts 4L and 5L (FHP) can be interchanged to the equivalent
“Classical” A or B v-belt. You can also use notched style v-belts which are designated by an AX or BX
prefix.
Notched v-belts are about 3% more efficient than wrapped style v-belts.
While A and B belts can be an excellent upgrade and substitute for 4L and 5L v-belts, the opposite is
not true. 4L and 5L belts have lower horsepower ratings and design life compared to Classical A and
B series v-belts. Using a 4L or 5L belt in an A or B application will result in reduced performance and
belt life.
Comparison Snapshot
Interchangeability
1/2” Top
Width
• 4L to A........................... 3
21/23” Top
Width
FHP V-Belts
4L
5L
1/2” Top
Width
21/23” Top
Width
• 5L to B........................... 3
• 5L to BX......................... 3
• A to 4L........................ NO
• AX to 4L...................... NO
• B to 5L........................ NO
Classic V-Belts
A/AX
• 4L to AX......................... 3
• BX to 5L...................... NO
B/BX
Converting from 4L and 5L v-belts to A/AX or B/BX brings several operational advantages which can
improve performance. The next page details horsepower differences of classical belts compared to
FHP.
Note: Notched V-belts Should Not be Used In Clutching Applications Where Slip Is Desired
Belt Drive Monthly
Volume 21• April 2010
Horsepower Capability
Below is a comparison of 5L FHP belts to B Section wrapped belts. FHP belts are typically for low
horsepower applications whereas B Section classical belts are for medium horsepower applications. Both of these belts will fit in the same sheave groove. In the example below, using a 5.4”
pitch diameter sheave, the 5L belt will transmit 2.39 horsepower. Using a B section belt on the
same 5.4” pitch diameter sheave can transmit 7.21 horsepower, which is three times the horsepower of the 5L belt. The 5L and the B Section belt will both fit in the same sheave but they provide
dramatically different horsepower capacities. In addition, FHP v-belts only have about 1/3rd the
design life of a Classical v-belt
Note : Using a BX belt in this example would increase rating to 9.19HP (a 285% HP design gain)
and provide an efficiency gain of about 3%. For a closer look at horsepower tables please order our
convenient reference guide (form 8932 - MCC08014) at www.RegalPTS.com or call us for design
assistance.
Special Note: Some competitor v-belts labeled with dual descriptions such as B (5L)
can be hybrid designs and may have lower horsepower capacity and design life
compared to the individual ratings listed above.
Regal Power Transmission Solutions
7120 New Buffington Rd
Florence, KY 41042
Customer Service: 800-626-2120
Fax: 800-262-3292
Technical Service: 800-626-2093
Future article ideas or questions can be
Submitted to [email protected]
www.RegalPTS.com
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