Although, it is not rocket science, there has been lot of confusion due to lack of awareness about simple rules. Industrial belts in section A, B, C, D, E, Z, AX, BX, CX belts have the designation of inside circumference measured in inches after the initial letter denoting the particular section based on cross-section, i.e., top width and height.

Accordingly, the outside circumference is different depending on what section is needed. For outside circumference per section, please note the following thumb rule:

• Z = Add 1"inch to belt number (Example Z38 = 39" outside circumference)
• A = Add 2"inches to belt number (Example A88 = 90" outside circumference)
• B = Add 3" inches to belt number (Example B88 = 91" outside circumference)
• C = Add 4" inches to belt number (Example C88 = 92" outside circumference)
• D = Add 5" inches to belt number (Example D105 =110" outside circumference)
• E = Add 6" inches to belt number (Example E144 = 150" outside circumference)
• AX = Add 2" inches to belt number (Example AX60 = 62" outside circumference)
• BX = Add 3" inches to belt number (Example BX50 = 53" outside circumference)
• CX = Add 4" inches to belt number (Example CX88 = 92" outside circumference)

For the following sections: 2L, 3L, 3V, 5V, 8V, 3VX, 5VX and 8VX belts have the outside circumference measured in 1/10th of an "inch after the number and letter(s).

Inside circumference are not measured for these sections. Accordingly, the outside circumference per section is given below:

• 2L = (Example 2L350 = 35" outside circumference)
• 3L = (Example 3L450 = 45" outside circumference)
• 4L = (Example 4L550 = 55" outside circumference)
• 3V/3VX = (Example 3V/ 3VX1000 = 100" outside circumference)
• 5V/5VX = (Example 5V/ 5VX1180 = 118" outside circumference)
• 8V/8VX = (Example 8V/ 8VX2120 = 212" outside circumference)

For the following wedge sections: SPZ, SPA, SPB, SPC, XPZ, XPA, XPB, and XPC these belts have the designation as pitch length measured in mm after the initial three letters denoting cross-section. The Pitch line length (Lp) of a V-belt is not the outside diameter (OR) the inside diameter, in fact it is the total length (circumference) of the belt measured along the load carrying cord of belt.

The pitch length (Lp) cannot be as easily measured as the inside length (Li) or the outside length (La) but there are simple formulae to arrive at Lp, if Li (or) La along with section is available.

• SPZ & XPZ (Lp = La-13 mm) or (Lp = Li+38 mm) SPA & XPA (Lp = La-18 mm) or (Lp = Li+45 mm)
• SPB & XPB (Lp = La-22 mm) or (Lp = Li+60 mm) SPC & XPC (Lp= La-30 mm) or (Lp = Li+83 mm)

(For further information or clarification contact SWR Belting. Tel: 0120- 4313588/89. Fax: 91-120-4151360. Email: info@swrbelting.com, sam@swrbelting.com, support@swrbelting.com)