Timing Belts & Pulleys
Through the manufacturers we distribute for, we have access to a large range of timing belts and pulleys. We can cater for the most powerful of industrial belts through to the lightest of drives, as well as replacement belts for supercharged cars.
Our main brands include Optibelt (Germany), Gates/Powergrip (USA), PTS Strongbelt (Germany) & PIX (India). If a specific brand is required that is not listed here we can source it at the right price for you. We have available timing belt catalogues for download and also a technical manual in our engineering section.
Timing Belts are one of the most important part of Power Transmission drives. They exhibit important properties such as fixed speed ratio, no re-tensioning after installation, low maintenance with wide variety of power transmission capacities and drive speeds. There are two main types of timing belt pulleys, they are to suit the classical timing belt and the metric HTD timing belts. Classical timing belt pulleys are imperial in their measurements, have a square profile and use the designations XL, L, H, XH & XXH, while the metric HTD pulleys have rounded profiled teeth and their designations are 3M, 5M, 8M and 14M.
Timing Belt Pulley
This image shows a classical timing belt drive pulley & belt, showing proper fitment and worn fitment. During inspection, check for worn tooth sections on the pulley. The correct fit for the pulley contact is shown. A small amount of clearance should exist between the root section of the pulley teeth to prevent the belt from bottoming out.
Generally, positive drive belt pulleys are flanged to help keep the belt in position. On long center drives, the belt may have a tendency to run to one side of the pulley. Stock or standard positive drive belts will ride toward the left flange, as indicated in the image to the right. If only one flange is located on the pulley, it should be placed on the left.
Minimum Pulley Diameters
This table identifies minimum recommended pulley diameters for each classical positive drive belt cross-section. Smaller diameter pulleys could be used other than what is recommended, but the belt life decreases.
Selecting Timing Belts
Classical positive drive belt sizes are:
- Pitch length
- Tooth pitch
- Belt width
The actual length of the belt is multiplied by ten to avoid use of decimals in belt codes. For example, a 22.5-inch long belt is a code 225. The width of the belt is multiplied by 100; a 3/4-inch is referred to as a code 075. Figure 39 provides examples of positive drive belt codes.
Metric HTD positive drive belt sizes are:
Example: 800 8M 30
800 = Pitch length 800mm
8M = Section (Tooth pitch 9.0mm)
30 = Belt width 30mm