Precision Timing Belts, Pulleys, Sprockets, and Chains for Synchronous Drive Systems
Why Choose Synchronous Drives?
SDP/SI is your trusted source for high-performance timing belts, pulleys, sprockets, and chain drive components. Engineered for precision and reliability, our synchronous drive solutions ensure accurate power transmission, zero slippage, and exceptional torque handling—even in demanding applications.
Synchronous drive systems rely on the positive engagement of meshing teeth, ensuring there’s no relative motion between components. This precise, slip-free transmission is essential for applications requiring timing accuracy, high torque, and controlled acceleration. Chain drives are often the go-to solution when ruggedness and shaft synchronization are paramount.
Belt Drive Systems
Belt drive systems offer a flexible, efficient, and quiet solution for transmitting power between shafts. They are especially useful in applications where component placement and system layout require greater center distances. Belt drives provide smooth operation, reduced vibration, and can accommodate misalignment better than many other drive types.
SDP/SI supplies a broad selection of timing belts in both inch and metric widths, including single- and double-sided profiles. Belts are available in fiberglass-reinforced neoprene and polyurethane with steel tensile cords for added strength and durability. For non-standard widths, timing belt sleeves can be cut to your exact specification—often with next-day turnaround for fast delivery. We also offer fractional HP V-belts and belt clamps.
To complete your drive system, SDP/SI also offers a full range of precision-machined pulleys in aluminum, steel, or plastic. Pulleys are available with or without metal inserts, set screws, hubs, or Fairloc® hub designs, providing options that suit both performance and installation needs. Available belt profiles include MXL, XL, L, T-series (T2.5, T5, T10), Gates HTD®, GT®2, GT®3, 40 D.P. and Miniature FHT® 1, 2, & 3 mm (To be discontinued).
Maintaining proper belt tension is critical to ensure consistent performance and extend belt life. SDP/SI offers belt tensioners and adjustment tools to help maintain optimal system performance. Whether you're building a new design or upgrading an existing one, our in-house engineering team is available to help you select or customize the ideal belt drive components for your application.
Sprocket and Chain Drive Systems
Sprocket and chain drive systems are a cost-effective and reliable method for transmitting power. The most efficient configuration typically involves a short-pitch, single-strand chain that meets the required design horsepower when paired with the appropriate sprocket size and speed. For best results, the center distance between sprockets should allow for at least 120° of chain wrap on the smaller sprocket—ensuring engagement with at least half of its teeth.
When selecting sprockets, those with 17 to 67 teeth are recommended for longer service life and smoother operation. However, in applications with space constraints or lower speeds, sprockets with fewer than 17 teeth may be used effectively. Chain longevity is highly dependent on proper lubrication; in fact, a well-lubricated chain can last more than 100 times longer than a poorly maintained one.
Ladder chain, constructed from interlocking wire links, offers an affordable and easy-to-install solution. It is commonly used in household appliances, vending machines, and a variety of timing and electrical devices. SDP/SI offers a comprehensive selection of roller and ladder chains in both inch and metric dimensions, along with matching plastic and metal sprockets. To ensure optimal performance and extend the life of your drive system, we also supply tensioning products and chain tension monitoring tools.
For more complex needs or custom applications, SDP/SI’s experienced engineering team is available to help you select the most suitable components for your chain drive system.
Built for Flexibility and Performance
Timing belts are ideal for applications requiring layout flexibility. They allow components to be positioned at greater distances without performance trade-offs. SDP/SI provides belt stock in fiberglass-reinforced neoprene and steel-cord reinforced polyurethane, with custom widths available—often with overnight turnaround.
Expert Engineering Support & Custom Solutions
Since 1950, SDP/SI has helped engineers build reliable, high-precision synchronous drive systems. Whether you need help selecting a standard catalog item or require a custom drive solution, our in-house engineering team is ready to assist. From design and prototyping to manufacturing and assembly, we ensure the highest levels of quality and performance.
Timing Belt and Pulley Center Distance Designer
Get the right pulley and timing belt combination and instantly identify the appropriate part numbers that meet your specifications. Click the video above to learn how to use it, or click the button below to get started.
Design Your Belt and Pulley Drive System
Helpful Links
Timing Belt Design and Installation Guidelines and Suggestions: General Guidelines
Timing Belt Design and Installation Guidelines and Suggestions: Operations
Download Belt and Pulley Technical Data
Custom and Secondary Operations
Shafts and Shaft Accessories
Learn more about Fairloc®
Learn more about Shaftloc®
Timing Belt Profiles
Available In:
Materials: Neoprene, Polymer Compound, Polyurethane, Nylon, Stainless SteelPitches: 1mm - 9.525mm or 3/8 in
Circular Pitches: 0.09820 in. (2.494mm) - 0.15708 in. (3.99mm)
Profiles: 40 DP, GT®, HTD®, L, MXL, Posi-Drive Synchromesh, T, XL
Timing belts come in a variety of tooth profiles, each designed for specific performance requirements. The tooth shape affects how the belt engages with the pulley, influencing load capacity, speed, noise, and wear. Common profiles include:
- MXL, XL, L – Classic trapezoidal profiles used in light- to medium-duty applications
- T-Series (T2.5, T5, T10) – Metric trapezoidal profiles ideal for general-purpose drives
- HTD® (High Torque Drive) – Curvilinear teeth designed for higher torque and load capacity
- Gates GT®2 and GT®3 – Advanced curvilinear profiles offering improved power transmission and reduced backlash
- NOTE: FHT® – 1mm and FHT® – 2mm timing belts will be discontinued when present stock is depleted. View availability.
Plastic and Metal Timing Pulleys
Available In:
Materials: Aluminum, Steel, Acetal, Nylon, PolycarbonatePitches: 0.080mm - 9.525mm
Profiles: 40 DP, GT®, HTD®, FHT®, L, MXL, T, XL
SDP/SI offers a wide range of precision timing pulleys in both inch and metric sizes, available in metal and molded plastic. Molded pulleys are offered with or without metal inserts, providing flexibility for different load and performance requirements. For each timing belt profile, you'll find an extensive selection of groove counts, belt widths, and flange options—including single-flange, double-flange, and no-flange designs. Custom bore sizes, keyways, and additional modifications are available upon request to meet specific application needs.
Timing Pulley Stock
Available In:
Materials: Aluminum, Steel, Carbon SteelProfiles: GT®, HTD®, FHT®, L, MXL, T, XL
Pitches: 3mm or 1/5 in
SDP/SI offers timing pulley stock in both aluminum and steel, with inch and metric options available. Choose from a wide range of groove counts and tooth profiles to suit your specific drive requirements. Visit our E-Store for current availability or contact our Sales Team for assistance with selection or custom options.
Shaftloc® Pulleys
Available In:
Materials: Nylon with Steel InsertPitches: 3/8mm or 1/5 in
Profiles: XL, L, HTD®
SDP/SI’s Shaftloc® timing pulleys are precision-molded with a durable metal insert for enhanced strength and performance. Available in both single-flange and double-flange configurations, these pulleys are designed to work seamlessly with our patented Shaftloc® fastening system — a unique, keyless solution that simplifies installation, improves concentricity, and provides a secure, backlash-free hold on the shaft. Ideal for applications where quick assembly and reliable performance are essential.
Cables and Fittings
Available In:
Materials: Stainless Steel, Nylon Coating with Brass FittingSDP/SI offers miniature stainless steel cable in outer diameters ranging from 0.024" to 1/8", sold in 10-foot increments. Each cable is nylon coated to reduce abrasion, protect pulleys, and retain internal lubrication for extended life and smoother performance. To complete your assembly, a variety of fittings are available, including threaded plugs, ball-end plugs, loop sleeves, and thimbles, all designed for precise and secure cable terminations.
Precision Posi-Drive Sprockets
Available In:
Materials: Stainless Steel, AluminumPitches: 20 & 32
Circular Pitches: 0.1475
Designed specifically for use with Posi-Drive belts, SDP/SI’s Posi-Drive sprockets offer a reliable, low-cost alternative to miniature steel chain systems. Available in aluminum or steel, these sprockets come with your choice of clamp-type or pin-type hubs for secure, easy integration into your drive assembly. Ideal for compact, lightweight applications where precision and cost efficiency are key.
Timing Belt Clamps
Available In:
Materials: Polycarbonate, AluminumProfiles: XL, L, HTD®, GT®2, AT, T, MXL
SDP/SI offers a wide selection of timing belt clamps designed for use in linear drive systems. Available in both plastic and aluminum, these clamps are compatible with single- and double-sided timing belts, providing secure, reliable fastening in a variety of motion control applications.
Flat Belts
Available In:
Materials: Woven Polyester, NeopreneSDP/SI’s 1/4 inch (6 mm) wide flat belts are engineered for high-speed applications, reaching speeds up to 20,000 feet per minute (6,100 meters/minute). Constructed from polyester woven cord with a durable black neoprene coating, these belts offer excellent strength, flexibility, and wear resistance. For custom requirements, non-standard widths can be quickly cut from in-stock sleeves to meet your exact specifications.
Flat Belt Pulleys
Available In:
Materials: Polycarbonate pulley with Brass or Aluminum insertSDP/SI offers inch and metric flat belt pulleys made from fiberglass-reinforced polycarbonate for strength and durability. Each pulley includes either a brass or aluminum insert and is available off-the-shelf for immediate use. For unique requirements, custom pulleys with non-standard diameters or special design features can be manufactured to your specifications or supplied drawings.
O-Rings for Linear Bearings
Available In:
Materials: NeopreneSDP/SI offers neoprene round endless belts, also known as O-rings, in a range of diameters and internal sizes for use in mechanical belt drive systems. These flexible, durable belts are ideal for use with companion and grooved pulleys, and are available in both standard and metric options through our online store.
Round Endless Belts
Available In:
Materials: NeopreneSDP/SI’s round endless belts are flexible, durable solutions for light-duty power transmission and conveying applications. Made from high-quality neoprene, these belts provide smooth, quiet operation and are resistant to wear, abrasion, and environmental factors. Available in a variety of diameters and lengths, round belts are compatible with grooved or companion pulleys and are ideal for use in packaging equipment, small machinery, and custom drive systems.
Rounthane Belts
Available In:
Materials: PolyurethaneSDP/SI offers non-slip polyurethane Rounthane belts in three diameters: 3/16", 1/4", and 5/16". Known for their flexibility and durability, these belts are ideal for use with companion pulleys and grooved idlers with diameters at least eight times the belt diameter. Rounthane belting can be installed in both open- and closed-loop drive configurations, making it a versatile solution for a variety of light-duty power transmission and conveying applications.
Rounthane Belt Connectors
Available In:
Materials: AluminumSDP/SI offers aluminum belt connectors specifically designed for use with our non-slip polyurethane Rounthane belts. These connectors provide a strong, reliable join for creating custom-length belts in the field, making them ideal for quick assembly or maintenance of open-loop drive systems.
Grooved Idler Pulleys
Available In:
Materials: Nylon, Acetal, Stainless SteelSDP/SI offers grooved idler pulleys designed to guide and tension round and polyurethane belts in linear and rotary motion systems. Made from durable materials and precisely machined for smooth operation, these pulleys help reduce belt wear and ensure proper tracking. Available in a variety of diameters and bore sizes, they are ideal for use with Rounthane belts and other round belt systems.
Grooved Pulleys
Available In:
Materials: Acetal, BrassSDP/SI offers both precision and commercial-grade grooved pulleys, available from stock for fast delivery. These pulleys are offered in stainless steel or molded construction with a brass insert, and are available in pin-type or clamp-type configurations. Ideal for guiding round belts in light-duty power transmission and motion control applications, they ensure reliable performance and smooth operation.
V-Belts
Available In:
Materials: Reinforced RubberPitches: 9.6 - 32
Available in both inch and metric sizes, these reinforced rubber V-belts deliver reliable performance for a wide range of power transmission applications. They are engineered to be oil- and heat-resistant, as well as static-dissipating, making them well-suited for demanding industrial environments. To complete your system, companion pulleys are also offered and readily available.
V-Belt Pulleys
Available In:
Materials: Nylon, Aluminum HubSDP/SI offers a range of companion pulleys for use with 1/4 inch (6 mm) V-belts, available in both inch and metric sizes. These pulleys are offered in molded plastic or molded with aluminum inserts for added strength and durability. Standard diameters range from 1 inch to 6 inches (25 mm to 152 mm), making them ideal for a variety of light-duty drive applications.
Idler Pulleys with Needle Bearing
Available In:
Materials: SteelSteel idler pulleys with needle-type bearings are designed to support and guide flat belts, V-belts, sprockets, and timing pulleys in a variety of power transmission and motion control systems. These precision components help maintain proper belt alignment and tension. SDP/SI offers these pulleys in standard bore sizes of 3/16", 1/4", and 1/2", with additional sizes available upon request.
Synchromesh Pulleys
Available In:
Materials: Acetal with Brass InsertPitches: .120 - .250
* Aluminum inserts used on .250 pitch pulleys.
Synchromesh pulleys feature helical grooves designed to precisely engage with the spiral configuration of synchromesh drive cables, ensuring smooth, slip-free motion in positioning and linear drive systems. These pulleys are available in .120", .150", .200", and .250" pitch options to match various application needs. SDP/SI offers a range of synchromesh pulleys ideal for use in compact, low-backlash systems requiring accurate motion control.
Synchromesh Attachments
Available In:
Materials: Copper, Stainless Steel, NylonA wide selection of attachments for synchromesh cable systems is available to support a variety of mounting and motion requirements. Options include loop sleeves, plugs, eyes for screw mounting, and stainless steel thimbles. Thimbles are especially useful for high-load applications, providing loop reinforcement and protecting the cable from wear in dynamic systems. These components ensure secure terminations and extended cable life in precision motion control setups.
Tension Testers
Available In:
Types: Pencil Type, Meter & AccessoriesSDP/SI offers a range of tension measurement tools to ensure precise belt or cable tensioning. Our pencil-type tension gauge is lightweight and easy to use, measuring deflection force up to 30 lbs for quick adjustments. For more accurate readings, we also provide digital tension meters, suitable for various belt and cable types in both static and dynamic systems. Additionally, we offer alternate sensors and replacement adapters to support and maintain the accuracy of your tensioning tools.
Flanges
Available In:
Materials: Aluminum, SteelPitches: 0.08 - 5
Profiles: GT®, HTD® L, MXL, T, XL, FHT®
A variety of flanges are available to support proper belt alignment and tracking in timing pulley systems. Offered in single- and double-flange configurations, they come in plastic, aluminum, or steel to meet different application demands. Flanges are available in both inch and metric sizes, and can be easily installed or removed for added design flexibility. SDP/SI provides these components to complement our extensive line of pulleys and drive system parts.
Belt & Chain Tensioners
Available In:
Materials: Aluminum or Steel with Nylon, Acetal, Steel, and Stainless Steel RollerProper tension is essential for maximizing the performance and lifespan of any drive system. Belt and chain tensioners help prevent slippage, reduce wear, and ensure smooth, reliable operation. A wide selection of tensioning solutions is available to suit various system configurations and load requirements. SDP/SI offers both standard and custom tensioners designed to maintain consistent tension and protect your equipment over time.
Ladder Chains
Available In:
Materials: Stainless Steel, Brass, SteelPitches: .167 - .375
Ladder chains are lightweight, flexible drive components made from interlocking wire links, commonly used in low-load timing, indexing, and synchronization applications. Available in a variety of materials, pitches, and lengths, these chains are ideal for compact mechanical systems where smooth, quiet operation is essential. Their open, ladder-like construction allows for easy installation, low inertia, and reliable performance in applications such as appliances, vending machines, and automated equipment. SDP/SI offers a broad range of ladder chains to support both prototyping and production needs.
Ladder Chain Sprockets
Available In:
Materials: Stainless Steel, Brass, Steel, AcetalPitches: .1227 - 3/8
A wide range of ladder chain sprockets is available in plastic, steel, stainless steel, and brass, providing durable and precise engagement with ladder chains across various applications. Offered in multiple pitches, bore sizes, and tooth counts, these sprockets are available off-the-shelf for fast integration into your system. SDP/SI supplies sprockets engineered for smooth operation and long-lasting performance in compact, low-load drive systems.
Roller Chains
Available In:
Materials: Stainless Steel, Nylatron GS, Polypropylene, Acetal, PolyvinylidenePitches: .1227 - 3/8
Choose from a comprehensive selection of roller chains designed for reliable power transmission in compact and high-performance applications. Options include sub-miniature and miniature roller chains, as well as plastic, stainless steel, and hardened steel roller chains to suit a variety of operating environments. Whether you're building a precision mechanism or an industrial system, SDP/SI offers the roller chain solutions you need for smooth, durable operation.
Roller Chain Sprockets
Available In:
Materials: Stainless Steel, Nylatron GS, Steel, Acetal, NylonPitches: .1227 - .250
A wide range of inch and metric roller chain sprockets is available as standard catalog items, designed for smooth and efficient operation with roller chains. Offered in various materials, pitches, tooth counts, and bore sizes starting as small as 3/32", these sprockets support a broad range of power transmission applications. Plastic and metal roller chains are also available to complete your drive system.
Monitoring and Maintenance Tools for Power Transmission Components
Ensure reliable performance and extended life of your power transmission components with easy-to-use monitoring and maintenance tools. Accurately align pulleys with compact devices that offer fast readings, display both parallel and angular misalignment, and support one-person operation on horizontally or vertically mounted machines. For safe, efficient bearing installation in the workshop or on-site, choose from portable handheld or table-top induction heaters that are energy-efficient and environmentally friendly. To prevent damage during installation, impact fitting tools are also available—helping you avoid premature bearing failure and costly downtime.