Per ISO 4184 / IS 2494 standard sections
mm — pitch diameter of motor/drive pulley
mm — pitch diameter of load pulley
mm — distance between pulley centres
RPM — typical motor: 1440 (4-pole) or 2880 (2-pole)
kW — motor rating
BELT LENGTH (Lp)
mm — pitch length
Speed ratio (i)
Driven speed (N₂)
Belt linear speed
Arc of contact (driver)
Tight-side tension
Slack-side tension
Lp = 2C + (π/2)(D₁+D₂) + (D₂−D₁)²/(4C)
v = π·D₁·N₁ / 60000 (m/s)
α = π − 2·sin⁻¹((D₂−D₁)/(2C))
T₁/T₂ = e^(μ·α/sin(β/2)) where β = 38° groove

V-belt section reference (IS 2494)

SectionTop widthThicknessMin D pulleyPower range (kW)
Z10 mm6 mm50 mm0.4 – 4
A13 mm8 mm75 mm0.75 – 7.5
B17 mm11 mm125 mm2 – 25
C22 mm14 mm200 mm5 – 75
D32 mm19 mm355 mm20 – 250
E38 mm23 mm500 mm50 – 500+