Tool

Belt & Pulley

V-belt and timing-belt sizing — drive ratios, driven speed and torque, belt length, wrap angle, belt speed, and an estimated belt count by cross-section.

V-belt drive

Units

Driver Ø (in)Driven Ø (in)Center distance (in)Driver RPMTransmitted HPCross-section

Speed

Ratio2.000 : 1

Driven RPM875.0

Belt speed1604 fpm488.8 m/min

Torque

Driver torque15.01 lbf·ft20.34 N·m

Driven torque30.01 lbf·ft40.69 N·m

Geometry

Belt length (in)52.66

Wrap on small pulley168.8°

Estimated belts needed2@ 3 HP/belt × 0.97 arc corr.

Belt count and HP/belt are ballpark only — actual capacity depends on pulley diameter, speed ratio, and service factor. Use the OEM rating chart (e.g., Gates, Bando) for production design.

Timing belt (synchronous)

Tooth counts and metric pitch. Belt length is rounded up to a whole number of teeth.

Driver teeth (N₁)Driven teeth (N₂)Center distance (mm)Pitch

Ratio2.000 : 1

Belt teeth (min)91

Belt length455.0 mm17.91 in

V-belt cross-section quick reference

Profile	Top width	Thickness	~HP / belt
3L (fractional)	0.375 in	0.219 in	0.5
4L (fractional)	0.500 in	0.281 in	1
5L (fractional)	0.625 in	0.375 in	1.5
A (classical)	0.500 in	0.310 in	3
B (classical)	0.660 in	0.410 in	7
C (classical)	0.875 in	0.530 in	14
D (classical)	1.250 in	0.750 in	28
3V (narrow)	0.375 in	0.310 in	5
5V (narrow)	0.625 in	0.530 in	15
8V (narrow)	1.000 in	0.910 in	35

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