Belts & Pulleys
Belts and Pulleys Basics
Common Terms
Pitch Diameter also known as PD is the circle that is formed while the belt and pulley are meshed together and which the belt rotates around. If you wish to find the PD, reference the formula below.
(Pitch x Number of T) ÷ π
Calculating Center to Center
How to Use WCP 's Belt Distance Calculator
WCP now offers a built-in calculator to provide all our customers with piece of mind when designing with belts and pulleys. If you are interested in viewing our calculator or knowing how to use it, see below for more information.
Use this calculator to find the correct center to center distance for belts (WCP Belt Calculator)
You will need a few pieces of information when using the WCP Belt Calculator:
Belt pitch to be used
3mm for GT2/GT3 belts
5mm for HTD Belts
Number of teeth for both pulleys
Approximate distance between centers of the two pulleys
The Output from the calculator will give you the belt center to center as well as the tooth count for the closet belt to the values entered. It will also give you the information for one belt size higher and lower.
Center to Center Equations
The equation below shows the minimum center distance that should be used.
The equation below shows the center distance for equally sized pulleys.
The examples below are places where a looser belt may be beneficial. Subtracting center distance can help reduce the overall load of the system which in turn reduces motor load and power consumption.
First Stage Reduction: -0.000 to -0.003
Intake Rollers: -0.015 to -0.020
Conveyor System: -0.015" to -0.020"
Recommended Applications
GT2 Belts
First stage reductions
Motor to flywheel
Low load
HTD Belts:
Intake or conveyor systems
Drivetrains
Medium load
GT2 Belts and Pulleys (Product Page)
GT2 timing belts are intended for lower load applications such as the first reduction in a gearbox, or motor to flywheel. GT2 belts use a smaller pitch than HTD belts, which means you can use larger reductions in those tight fit areas of your robot.
All GT2 Pulleys will now be clocked and engraved. An alignment notch has also been added to help with clocking multiple items together during assembly.
GT2 Pulleys
| Bore | Width | # of Teeth |
|---|---|---|
8mm SplineXS | 9mm/15mm | 16 |
Falcon Spline | 9mm/15mm | 16 |
RS550 Motor/RS775 Motor/BAG Motor | 9mm | 12 |
1/2" Hex | 9mm | 24, 36, 48, 60 |
These pulleys are compatible with GT2 and GT3 belts.
GT2 Belts
| Width | # of Teeth |
|---|---|
9mm | 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 140, 150, 160, 170,180 |
HTD Belts and Pulleys
Synchronous timing belts are lighter and more efficient than chain. Once set up, they require no tensioning or adjustment. The HTD profile is ideal for FIRST ® Robotics Competition applications - its deep tooth profile allows it to better handle high reversing loads, such as those found in an FIRST ® Robotics Competition drivetrain.
All HTD Pulleys will now be clocked and engraved. An alignment notch has also been added to help with clocking multiple items together during assembly.
HTD Pulleys (Product Page)
| Width | Bore | # of Teeth |
|---|---|---|
9mm/15mm | 8mm SplineXS | 12 |
9mm/15mm | 8mm Key, Falcon | 12 |
9mm | 1/2" Hex | 15, 18, 24, 30, 36 |
15mm | 1/2" Hex | 15, 18, 24, 30, 36 |
HTD Belts (Product Page)
| Width | # of Teeth |
|---|---|
9mm | 30, 35, 40, 45, 50, 53, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 104, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 160, 170, 180, 190, 200, 225, 250 |
15mm | 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 104, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 160, 170, 180, 190, 200, 225, 250 |
18mm | 25ft |
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