Timing Belts - Precision Cut to Standard and Custom Widths for Superior Performance.

40 Diametral Pitch (or 2.07 mm) Timing Belts

SDP/SI offers a wide selection of standardized mechanical components including 40 D.P. (2.07 mm) Pitch timing belts and pulleys. The timing belts are available off-the-shelf in 9 standard inch and metric widths. Special widths can be cut to size from sleeves available from stock. Aluminum pulleys, molded plastic pulleys with brass inserts and molded plastic pulleys without inserts are offered.

  • FHT Timing Belts

The FHT (Fenner High Torque) curvilinear timing belt system provides smooth operation and high torque carrying capacity with low backlash. These mini-pitch synchronous timing belts and pulleys are available in the following pitches: 1 mm, 2 mm and 3 mm. The miniature pitch was designed in response to the growing need for smaller belt drives in today's market place. Precise positioning, quiet operation and low vibration, the mini-pitch drive system provides years of trouble-free service for many applications, including 3D Printers, Pan and Tilt functions, Medical Devices and Vending Machines.

  • Gates GT® 2 Timing Belts

The PowerGrip GT2 Belt Drive System is an advance in product design over the Gates‘ older, standard HTD system, providing higher torque carrying capability and improved load carrying strength.

The PowerGrip GT3 Belt Drive System is the newest design and offers additional benefits over GT2. The improved construction and material compound provides superior load bearing capacity. The GT2 Belts are being phased out and replaced by the new GT3 Belt Drive System

Both the PowerGrip GT2 and GT3 System‘s deep tooth design increases the contact area which provides improved resistance to ratcheting. The modified curvilinear teeth enter and exit the pulley grooves cleanly, resulting in reduced vibration.

These belts and pulleys are available in 2 mm, 3 mm & 5 mm pitches and provide the following advantages:

• Longer belt life
• Precision registration
• Increased load-carrying capacity
• Quieter operation
• Precise positioning

Application Examples for the PowerGrip GT2 and GT3 drive systems: Machine Tools, Hand Power Tools, 3D-Printers, Medical Diagnostic Equipment, Automated Teller Machines, Robotics Equipment, and Vending Equipment.

The efficiency and integrity of a belt drive is closely attributed to the quality of pulleys involved. The pulleys therefore, should be supplied by qualified and licensed suppliers. Stock Drive Products is licensed by Gates. The GT2/GT3 pulleys manufactured by Stock Drive Products are made using licensed hobs, achieving the precise fit for the drive system. The pulleys offered here will mesh perfectly with either the GT2 or GT3 belt.

  • Gates GT® 3 Timing Belts

 Gates HTD® Timing Belts

The trapezoidal shape timing belt was superseded by a curvilinear tooth profile. Because of their superior load carrying capabilities, the curvilinear belts are marketed under the name of Gates’ HTD drives. This is an abbreviation of High Torque Drives.

Advantages of this type of drive are as follows:

• Proportionally deeper tooth; hence tooth jumping or loss of relative position is less probable.
• Lighter construction, with correspondingly smaller centrifugal loss.
• Smaller unit pressure on the tooth since area of contact is larger.
• Greater shear strength due to larger tooth cross section.
• Lower cost since a narrower belt will handle larger load.
• Energy efficient, particularly if replacing a “V” belt drive which incurs energy losses due to slippage.
• Installation tension is small, therefore, light bearing loads.

L Profile Timing Belts

3/8" (9.525 mm) Pitch L timing belts, aluminum pulleys, steel pulleys and molded plastic pulleys with either steel or aluminum inserts are available. Modifications can be quickly made when your design calls for a non-standard item.

Synchronous drives are especially well-suited for low-speed, high-torque applications. Their positive driving nature prevents potential slippage associated with V-belt drives, and even allows significantly greater torque carrying capability. Small pitch synchronous drives operating at speeds of 50 ft/min or less are considered to be low-speed.

MXL Profile Timing Belts

Positive drive belt systems were first developed with a trapezoidal profile, such belts are MXL, XL and L. MXL timing belts are made of Polyurethane, reinforced with either Polyester or Kevlar cord or Nylon covered Neoprene, Fiberglass reinforced. Five standard widths are available and when required other widths can be cut to order.

One of the benefits of small synchronous belt drives is lower belt pre-tensioning in comparison to comparable V-belt drives, but proper installation tension is still important in achieving the best possible drive performance. Tension that is too high can reduce belt life and possibly damage other drive components such as shafts and bearings. Belt installation tension is measured in the following ways: Force/Deflection, Shaft Separation, Idler Force or by using a Tension Tester. Two types of Tension Testers are available from SDP/SI for quick, easy and accurate tension testing.

Posi-Drive Synchronous Belts

Single and double core posi-drive belts and sprockets are suitable for applications that require accurate positioning. The no-slip design offers several distinct advantages:

• No flanges are required, which saves space, and also prevents the trapping of air between the belt and the flanges, creating a much quieter operation.


• The system also operates with no backlash, which is essential for applications that require no lost motion. 3D printers can benefit from this advantage, since more precise positioning will result in better quality parts.

Yet another advantage of the posi-drive system is that the single core belts and sprockets can be used in applications where the shafts are oriented at an angle with one another. The central core, made of either aramid fiber or stainless steel, can twist in such a way that the pins still stay in perfect mesh with the sprocket. This allows the shafts on either sprocket to be oriented at a full 90° angle without sacrificing belt performance.

The posi-drive belts are made of molded polyurethane and require no lubrication. They have excellent chemical and abrasion resistance, making them suitable for medical and food processing applications as well.

Synchromesh Drive System

Synchromesh Drive System for reciprocating motion applications

In a synchromesh drive system, the drive cable replaces conventional timing belts. The cable consists of a core bundle of stranded stainless steel wires encapsulated in a nylon jacket. Wound spirally around the nylon jacket is another cable of similar construction. The spiral member is bonded to the core cable to provide functional stability under load. The pitch of the spiral winding is carefully controlled during the winding and bonding processes. The use of stranded wire and nylon resin produces an extremely flexible cable that opens up many new design possibilities.

Synchromesh drive pulleys have helical grooves on their outside diameter, to accurately engage the spiral convolutions on the drive cable. Cables up to 200 feet long, machined or molded pulleys, mounting attachments and end fittings are available at SDP/SI.

This video shows how the Synchromesh Cable works for linear motion. 

T Profile Timing Belt

T single-sided and double-sided timing belts are available in pitches 2.5, 5 and 10 mm. Made of polyurethane and reinforced with strong fiberglass tensile cords they are oil and ozone resistant. Fiberglass tensile cords provide many advantages including, high strength, low elongation, absence of creep and excellent dimensional stability. For a lightweight drive system pair these polyurethane timing belts with either aluminum pulleys or plastic pulleys.

XL Profile Timing Belt

1/5" (5.08 mm) Pitch XL timing belts are available in standard widths: 1/4", 5/16", 3/8", and 1/2". As all our belts, XL timing belts can be cut to non-standard widths to meet your exact needs. XL timing belts are stocked in 21 thru 590 grooves. Aluminum pulleys, steel pulleys, molded plastic pulleys, plastic pulleys with over-molded aluminum hubs, and plastic pulleys with aluminum inserts are available as standardized items. When a standard product won't meet your requirements we can provide alternative solutions through custom design and manufacturing. Our engineering and manufacturing teams will partner with you throughout the entire process. By providing design, development, manufacturing, assembly and testing in one location we can ensure the end product will meet your expectations. We specialize in both small to large production runs.