Flat-Belt Idler Pulleys
These pulleys spin freely on built-in bearings to maintain tension for reduced wear and vibration. They’re often used with belt tensioners (sold separately).
Nylon pulleys are lightweight and corrosion resistant. Steel and cast iron pulleys are more durable than nylon pulleys.
Pulleys with ball bearings ensure proper positioning inside a tube or housing. They’re sealed to block out dust and contaminants better than pulleys with needle roller bearings.
Pulleys with needle roller bearings minimize internal friction.
For technical drawings and 3-D models, click on a part number.
| For Belt Wd. | OD | For Shaft Dia. | Dia. | Wd. | Groove Dp. | Material | Each | |
With Ball Bearings | ||||||||
|---|---|---|---|---|---|---|---|---|
| 5/8" | 3 1/2" | 3/8" | 3" | 1 3/32" | 0.25" | Nylon Plastic | 0000000 | 000000 |
| 5/8" | 3 1/2" | 1/2" | 3" | 1 3/32" | 0.25" | Nylon Plastic | 0000000 | 00000 |
| 11/16" | 2 1/2" | 0.635" | 2 1/4" | 7/8" | 0.125" | Cast Iron | 0000000 | 00000 |
| 13/16" | 2.8" | 3/8" | 2 33/64" | 1 7/32" | 0.11" | Nylon Plastic | 0000000 | 00000 |
| 13/16" | 2.8" | 1/2" | 2 33/64" | 1 7/32" | 0.11" | Nylon Plastic | 0000000 | 00000 |
| 13/16" | 3 1/2" | 3/8" | 3" | 1 7/32" | 0.25" | Nylon Plastic | 0000000 | 00000 |
| 13/16" | 3 1/2" | 1/2" | 3" | 1 7/32" | 0.25" | Nylon Plastic | 0000000 | 00000 |
| 7/8" | 2.4" | 3/8" | 2" | 1 5/32" | 0.18" | Nylon Plastic | 0000000 | 00000 |
| 7/8" | 2.4" | 1/2" | 2" | 1 5/32" | 0.18" | Nylon Plastic | 0000000 | 00000 |
| 7/8" | 3" | 3/8" | 2 1/2" | 1 5/16" | 0.25" | Nylon Plastic | 0000000 | 00000 |
| 7/8" | 3" | 1/2" | 2 1/2" | 1 5/16" | 0.25" | Nylon Plastic | 0000000 | 00000 |
| 7/8" | 5.6" | 3/8" | 5 1/32" | 1 19/64" | 0.26" | Nylon Plastic | 0000000 | 00000 |
| 7/8" | 5.6" | 1/2" | 5 1/32" | 1 19/64" | 0.26" | Nylon Plastic | 0000000 | 00000 |
| 29/32" | 4 1/2" | 3/8" | 4" | 1 25/64" | 0.25" | Nylon Plastic | 0000000 | 00000 |
| 29/32" | 4 1/2" | 1/2" | 4" | 1 25/64" | 0.25" | Nylon Plastic | 0000000 | 00000 |
| 1 1/16" | 4 1/2" | 0.635" | 4" | 1 7/16" | 0.25" | Cast Iron | 0000000 | 000000 |
| 1 1/8" | 2.1" | 3/8" | 1 7/8" | 1 35/64" | 0.09" | Nylon Plastic | 0000000 | 00000 |
| 1 1/8" | 2.1" | 1/2" | 1 7/8" | 1 35/64" | 0.09" | Nylon Plastic | 0000000 | 00000 |
| 1 1/8" | 3.4" | 3/8" | 2 31/32" | 1 43/64" | 0.2" | Nylon Plastic | 0000000 | 00000 |
| 1 1/8" | 3.4" | 1/2" | 2 31/32" | 1 43/64" | 0.2" | Nylon Plastic | 0000000 | 00000 |
| 2 1/16" | 4 1/2" | 0.635" | 4" | 2 7/16" | 0.25" | Cast Iron | 0000000 | 000000 |
| 3 1/16" | 4 1/2" | 0.635" | 4" | 3 7/16" | 0.25" | Cast Iron | 0000000 | 000000 |
| 4 1/2" | 7" | 1" | 6" | 5" | 0.5" | Cast Iron | 0000000 | 000000 |
| 6 1/4" | 7" | 1" | 6" | 6 3/4" | 0.5" | Cast Iron | 0000000 | 000000 |
With Needle Roller Bearings | ||||||||
| 7/16" | 1.4" | 1/2" | 1 1/8" | 5/8" | 0.125" | Steel | 000000 | 00000 |
| 9/16" | 1.8" | 1/2" | 1 3/8" | 13/16" | 0.187" | Steel | 000000 | 00000 |
| 11/16" | 2 1/2" | 1" | 2 1/4" | 7/8" | 0.125" | Steel | 000000 | 00000 |
| 1 1/16" | 4 1/2" | 1" | 4" | 1 7/16" | 0.25" | Cast Iron | 000000 | 00000 |
| 2 1/16" | 4 1/2" | 1" | 4" | 2 7/16" | 0.25" | Cast Iron | 000000 | 000000 |
| 3 1/16" | 4 1/2" | 1" | 4" | 3 7/16" | 0.25" | Cast Iron | 000000 | 000000 |
| 4 1/2" | 7" | 1 1/2" | 6" | 5" | 0.5" | Cast Iron | 0000000 | 000000 |
Timing Belt Idler Pulleys
Add these free-spinning pulleys to your timing belt setup to minimize vibration and keep belts from wearing out. The needle bearing at the center of these pulleys is lined with small, cylindrical rollers that reduce friction as they rotate. This bearing allows both the pulley and the shaft it’s mounted on to spin independently. Made from iron or steel, these pulleys are strong and wear-resistant. The black oxide coating protects the pulleys from corrosion in dry environments.
Trapezoidal teeth on the outside of the pulley fit into teeth inside your timing belt—select a pulley that matches your belt trade size. The maximum belt width should be the same size or larger than the width of your timing belt.
Curved teeth have more surface contact with belts than traditional trapezoidal teeth, which allows you to apply more torque without damaging belts. These teeth fit together seamlessly to prevent backlash, or unwanted movement of the belt on the pulley, for a smooth, quiet cycle. They are also known as curvilinear belt pulleys.
For technical drawings and 3-D models, click on a part number.
| For Max. Belt Wd. | OD | Number of Teeth | Teeth Shape | For Shaft Dia. | Pitch | Dia. | Bore Type | Overall Wd. | Pitch Dia. | Fabrication | Material | Bearing Type | Hub Dia. | Each | |
For H Belt Trade Size  | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1" | 2 1/2" | 16 | Trapezoidal | 1" | 0.5" | 2 1/2" | Plain | 1 1/8" | 2.546" | Machined | Black-Oxide Steel | Needle Roller | 1.8" | 0000000 | 000000 |
| 2" | 2 1/2" | 16 | Trapezoidal | 1" | 0.5" | 2 1/2" | Plain | 2 1/8" | 2.546" | Machined | Black-Oxide Steel | Needle Roller | 1.85" | 0000000 | 00000 |
| 3" | 2.8" | 18 | Trapezoidal | 1" | 0.5" | 2 1/2" | Plain | 3 1/8" | 2.865" | Machined | Black-Oxide Iron | Needle Roller | 1 3/4" | 0000000 | 000000 |
For L Belt Trade Size | |||||||||||||||
| 1" | 2.1" | 18 | Trapezoidal | 1" | 0.375" | 2 1/8" | Plain | 1 1/8" | 2.149" | Machined | Black-Oxide Steel | Needle Roller | 1 3/4" | 0000000 | 00000 |
| 1" | 2.6" | 22 | Trapezoidal | 1" | 0.375" | 2 19/32" | Plain | 1 1/8" | 2.626" | Machined | Black-Oxide Steel | Needle Roller | 1 3/4" | 0000000 | 00000 |
For XL Belt Trade Size | |||||||||||||||
| 1/2" | 1 1/2" | 24 | Trapezoidal | 1/2" | 0.2" | 1 1/2" | Plain | 1/2" | 1.528" | Machined | Black-Oxide Steel | Needle Roller | 1.21" | 0000000 | 00000 |
| 3/4" | 1.4" | 22 | Trapezoidal | 1/2" | 0.2" | 1 3/8" | Plain | 3/4" | 1.401" | Machined | Black-Oxide Steel | Needle Roller | __ | 0000000 | 00000 |
| For Max. Belt Wd., mm | OD, mm | Number of Teeth | Teeth Shape | Pitch, mm | For Shaft Dia., mm | Dia., mm | Bore Type | Inside Wd., mm | Outside Wd., mm | Overall Wd., mm | Pitch Dia., mm | Number of Flanges | Fabrication | Material | Bearing Type | Hub Dia., mm | Each | |
For GT Belt Trade Size | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 20 | 90 | 32 | Curved | 8 | 20 | 80.12 | Plain | 20 | 31.5 | 46.23 | 81.48 | 2 | Machined | Black-Oxide Iron | Needle Roller | 69.85 | 0000000 | 0000000 |
| 30 | 100 | 36 | Curved | 8 | 30 | 90.3 | Plain | 30 | 48 | 48 | 91.67 | 2 | Machined | Black-Oxide Iron | Needle Roller | __ | 0000000 | 000000 |
For GT2 Belt Trade Size | ||||||||||||||||||
| 21 | 90 | 32 | Curved | 8 | 20 | 79.88 | Plain | 21 | 31.5 | 45.97 | 81.48 | 2 | Machined | Black-Oxide Iron | Needle Roller | 69.85 | 0000000 | 000000 |
| 37 | 146 | 30 | Curved | 14 | 40 | 130.89 | Plain | 37 | 52.32 | 58.67 | 133.68 | 2 | Machined | Black-Oxide Iron | Needle Roller | 111 | 0000000 | 000000 |
| 62 | 100 | 36 | Curved | 8 | 30 | 90.07 | Plain | 62 | 73.91 | 91.19 | 91.67 | 2 | Machined | Black-Oxide Iron | Needle Roller | 79.5 | 0000000 | 000000 |
High-Strength HTD Timing Belt Idler Pulleys
Keep high torque drive (HTD) timing belt systems running tightly with these idler pulleys. Made with built-in, free-spinning ball bearings, they're installed on shafts or belt tensioners (not included) to remove slack from timing belts. By maintaining tension on the belt, these pulleys reduce wear and vibration in 3D printing, machine tool drives, robotics, and other linear motion applications that require precise positioning.
When replacing an idler pulley, be sure the pulley matches your belt's trade size.
Toothed pulleys are shaped to mesh with the teeth on a timing belt, which reduces wear on the belt's teeth.
Smooth pulleys have no teeth; they're used with the smooth side of the belt.
Iron pulleys are strong and wear resistant, with a black oxide coating that protects them from corrosion in dry environments.
For technical drawings and 3-D models, click on a part number.
| Manufacturer Series | OD | Number of Teeth | For Shaft Dia. | Dia. | Wd. | Groove Dp. | Shaft Mount Type | Bore Type | Number of Flanges | Fabrication | Material | Bearing Type | Each | |
For 6 mm Max. Belt Wd. | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Gates PowerGrip 2GT | 15mm | 20 | 3mm | 12.22mm | 10mm | 1.39 mm | Slip Fit | Finished | 2 | Machined | Aluminum | Ball | 00000000 | 00000 |
| Gates PowerGrip 2GT | 15mm | 20 | 5mm | 12.22mm | 10mm | 1.39 mm | Slip Fit | Finished | 2 | Machined | Aluminum | Ball | 0000000 | 0000 |
For 9 mm Max. Belt Wd. | ||||||||||||||
| Gates PowerGrip 2GT | 15mm | 20 | 3mm | 12.22mm | 14mm | 1.39 mm | Slip Fit | Finished | 2 | Machined | Aluminum | Ball | 00000000 | 0000 |
| Gates PowerGrip 2GT | 15mm | 20 | 5mm | 12.22mm | 14mm | 1.39 mm | Slip Fit | Finished | 2 | Machined | Aluminum | Ball | 0000000 | 0000 |
For 12 mm Max. Belt Wd. | ||||||||||||||
| Gates PowerGrip 2GT | 15mm | 20 | 3mm | 12.22mm | 16mm | 1.39 mm | Slip Fit | Finished | 2 | Machined | Aluminum | Ball | 00000000 | 0000 |
| Gates PowerGrip 2GT | 15mm | 20 | 5mm | 12.22mm | 16mm | 1.39 mm | Slip Fit | Finished | 2 | Machined | Aluminum | Ball | 0000000 | 0000 |
For 30 mm Max. Belt Wd. | ||||||||||||||
| __ | 1.85" | 19 | 1" | 1.85" | 1 5/16" | __ | Press Fit | Plain | __ | Machined | Black-Oxide Iron | Needle Roller | 0000000 | 00000 |
| Manufacturer Series | OD, mm | For Shaft Dia., mm | Dia., mm | Wd., mm | Groove Dp., mm | Shaft Mount Type | Bore Type | Number of Flanges | Fabrication | Material | Bearing Type | Each | |
For 6 mm Max. Belt Wd. | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Gates PowerGrip 2GT | 15 | 3 | 12 | 10 | 1.5 | Slip Fit | Finished | 2 | Machined | Aluminum | Ball | 00000000 | 00000 |
| Gates PowerGrip 2GT | 15 | 5 | 12 | 10 | 1.5 | Slip Fit | Finished | 2 | Machined | Aluminum | Ball | 0000000 | 0000 |
For 9 mm Max. Belt Wd. | |||||||||||||
| Gates PowerGrip 2GT | 15 | 3 | 12 | 14 | 1.5 | Slip Fit | Finished | 2 | Machined | Aluminum | Ball | 00000000 | 0000 |
| Gates PowerGrip 2GT | 15 | 5 | 12 | 14 | 1.5 | Slip Fit | Finished | 2 | Machined | Aluminum | Ball | 0000000 | 0000 |
For 12 mm Max. Belt Wd. | |||||||||||||
| Gates PowerGrip 2GT | 15 | 3 | 12 | 16 | 1.5 | Slip Fit | Finished | 2 | Machined | Aluminum | Ball | 00000000 | 0000 |
| Gates PowerGrip 2GT | 15 | 5 | 12 | 16 | 1.5 | Slip Fit | Finished | 2 | Machined | Aluminum | Ball | 0000000 | 0000 |
Constant-Tension V-Belt Pulleys
A built-in spring maintains tension on your belt.
For technical drawings and 3-D models, click on a part number.
Keyway | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| OD | For Shaft Dia. | Pitch Dia. | Wd. | O'all Wd. | Wd. | Dp. | Material | Body Type | Includes | Each | |
For 4L, 5L, A, AX, B, BX Belts | |||||||||||
| 3.25" | 1/2" | 1.91"-3.15" | 11/16" | 2 3/8" | __ | __ | Cast Iron | Solid | One Set Screw | 0000000 | 000000 |
| 3.25" | 5/8" | 1.91"-3.15" | 11/16" | 2 3/8" | 3/16" | 3/32" | Cast Iron | Solid | One Set Screw | 0000000 | 00000 |
| 3.25" | 3/4" | 1.91"-3.15" | 11/16" | 2 3/8" | 3/16" | 3/32" | Cast Iron | Solid | One Set Screw | 0000000 | 00000 |
| 4" | 1/2" | 1.95"-3.9" | 11/16" | 2 7/16" | __ | __ | Cast Iron | Solid | One Set Screw | 0000000 | 000000 |
| 4" | 5/8" | 1.95"-3.9" | 11/16" | 2 7/16" | 3/16" | 3/32" | Cast Iron | Solid | One Set Screw | 0000000 | 000000 |
| 4" | 3/4" | 1.95"-3.9" | 11/16" | 2 7/16" | 3/16" | 3/32" | Cast Iron | Solid | One Set Screw | 0000000 | 000000 |
| 5" | 5/8" | 2.37"-4.84" | 15/16" | 3 5/8" | 3/16" | 3/32" | Cast Iron | Solid | One Set Screw | 0000000 | 000000 |
| 5" | 3/4" | 2.37"-4.84" | 15/16" | 3 5/8" | 3/16" | 3/32" | Cast Iron | Solid | One Set Screw | 0000000 | 000000 |
| 5" | 7/8" | 2.37"-4.84" | 15/16" | 3 5/8" | 3/16" | 3/32" | Cast Iron | Solid | One Set Screw | 0000000 | 000000 |
| 5" | 1" | 2.37"-4.84" | 15/16" | 3 5/8" | 1/4" | 1/8" | Cast Iron | Solid | One Set Screw | 0000000 | 000000 |
V-Belt Idler Pulleys
These pulleys spin freely on built-in ball bearings to maintain tension for reduced wear and vibration. Commonly used with belt tensioners (sold separately), they are lightweight and corrosion and abrasion resistant. Bearings are double sealed to keep dirt out.
For technical drawings and 3-D models, click on a part number.
| No. of Grooves | OD | For Shaft Dia. | Pitch Dia. | Wd. | Groove Dp. | Material | Body Type | Each | |
For 4L, A, AX Belts | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| 1 | 3" | 3/8" | 2" | 45/64" | 0.5" | Nylon Plastic | Solid | 0000000 | 000000 |
| 1 | 3" | 1/2" | 2" | 45/64" | 0.5" | Nylon Plastic | Solid | 0000000 | 00000 |
| 1 | 4" | 3/8" | 2.99" | 45/64" | 0.5" | Nylon Plastic | Solid | 0000000 | 00000 |
| 1 | 4" | 1/2" | 2.99" | 45/64" | 0.5" | Nylon Plastic | Solid | 0000000 | 00000 |
| 1 | 6" | 1/2" | 5.12" | 23/32" | 0.46" | Nylon Plastic | Solid | 0000000 | 00000 |
| 1 | 7.5" | 1/2" | 6.6" | 23/32" | 0.45" | Nylon Plastic | Solid | 0000000 | 00000 |
For 5L, B, BX Belts | |||||||||
| 1 | 3.1" | 3/8" | 1.84" | 25/32" | 0.63" | Nylon Plastic | Solid | 0000000 | 00000 |
| 1 | 3.1" | 1/2" | 1.84" | 25/32" | 0.63" | Nylon Plastic | Solid | 0000000 | 00000 |
| 1 | 4" | 3/8" | 2.84" | 55/64" | 0.58" | Nylon Plastic | Solid | 0000000 | 00000 |
| 1 | 4" | 1/2" | 2.84" | 55/64" | 0.58" | Nylon Plastic | Solid | 0000000 | 00000 |
| 1 | 5" | 3/8" | 3.84" | 51/64" | 0.6" | Nylon Plastic | Solid | 0000000 | 00000 |
| 1 | 5" | 1/2" | 3.84" | 51/64" | 0.6" | Nylon Plastic | Solid | 0000000 | 00000 |
| 2 | 6.3" | 1/2" | 5.18" | 1 23/32" | 0.55" | Nylon Plastic | Solid | 00000000 | 000000 |
| 3 | 6.3" | 1/2" | 5.18" | 2 7/16" | 0.55" | Nylon Plastic | Solid | 00000000 | 000000 |
Round-Belt Idler Pulleys
These pulleys spin freely on built-in bearings to maintain tension for reduced wear and vibration. They are often used with belt tensioners (sold separately). Ball bearings are double sealed to keep dirt out.
Brass pulleys are nonsparking and fit in extremely small spaces. Nylon pulleys are lightweight and corrosion and abrasion resistant.
For technical drawings and 3-D models, click on a part number.
| For Belt Dia. | OD | For Shaft Dia. | Dia. | Wd. | Groove Dp. | Material | Bearing Material | Each | |
| 3/32" | 0.8" | 1/8" | 0.654" | 9/64" | 0.048" | Brass | Stainless Steel | 000000 | 000000 |
| 3/32" | 1" | 1/8" | 0.904" | 5/32" | 0.048" | Brass | Stainless Steel | 000000 | 00000 |
| 3/32" | 1.5" | 1/8" | 1.404" | 5/32" | 0.048" | Brass | Stainless Steel | 000000 | 00000 |
| 1/8" | 1" | 1/4" | 0.872" | 3/16" | 0.064" | Brass | Stainless Steel | 000000 | 00000 |
| 1/8" | 1.5" | 1/4" | 1.372" | 3/16" | 0.064" | Brass | Stainless Steel | 000000 | 00000 |
| 1/8" | 1.5" | 1/4" | 1.372" | 13/64" | 0.064" | Brass | Stainless Steel | 000000 | 00000 |
| 1/8" | 2" | 1/4" | 1.872" | 13/64" | 0.064" | Brass | Stainless Steel | 000000 | 00000 |
| 3/16" | 2" | 3/8" | 1.81" | 9/32" | 0.095" | Brass | Stainless Steel | 000000 | 00000 |
| 3/16" | 2.5" | 3/8" | 2.31" | 9/32" | 0.095" | Brass | Stainless Steel | 0000000 | 00000 |
| 1/4" | 4.5" | 3/8" | 3.74" | 55/64" | 0.36" | Nylon Plastic | Steel | 00000000 | 00000 |
| 1/4" | 4.5" | 1/2" | 3.74" | 55/64" | 0.36" | Nylon Plastic | Steel | 00000000 | 00000 |
| 1/4" | 6" | 3/8" | 5.2" | 51/64" | 0.4" | Nylon Plastic | Steel | 00000000 | 00000 |
| 1/4" | 6" | 1/2" | 5.2" | 51/64" | 0.4" | Nylon Plastic | Steel | 00000000 | 00000 |
| 3/8" | 3.1" | 3/8" | 2.45" | 39/64" | 0.3" | Nylon Plastic | Steel | 00000000 | 00000 |
| 3/8" | 3.1" | 1/2" | 2.45" | 39/64" | 0.3" | Nylon Plastic | Steel | 00000000 | 00000 |
| 3/8" | 3.5" | 3/8" | 2.75" | 49/64" | 3/8" | Nylon Plastic | Steel | 00000000 | 00000 |
| 3/8" | 3.5" | 1/2" | 2.75" | 49/64" | 3/8" | Nylon Plastic | Steel | 00000000 | 00000 |
| 3/8" | 5.5" | 3/8" | 4.62" | 9/16" | 0.44" | Nylon Plastic | Steel | 00000000 | 00000 |
| 3/8" | 5.5" | 1/2" | 4.62" | 9/16" | 0.44" | Nylon Plastic | Steel | 00000000 | 00000 |
| 11/16" | 4.8" | 3/8" | 4" | 1 1/16" | 0.41" | Nylon Plastic | Steel | 00000000 | 00000 |
| 11/16" | 4.8" | 1/2" | 4" | 1 1/16" | 0.41" | Nylon Plastic | Steel | 00000000 | 00000 |