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Reliable GT2 Smooth Idler Pulley with bearing, 5mm bore, 2mm pitch, and support for GT2 belts up to 9mm wide in 3D printers, CNC machines, robotics, and custom motion systems.
$4.95
The GT2 Smooth Idler Pulley is a free-spinning belt guide pulley used to route, support, or tension the smooth back side of a GT2 timing belt. This pulley includes a bearing, has a 5mm bore, uses a 2mm GT2 pitch system, and supports belts up to 9mm wide. It is commonly used in 3D printers, CNC machines, robotics platforms, laser engravers, plotters, belt tensioners, CoreXY motion systems, and custom mechanical assemblies.
Unlike a toothed GT2 drive pulley that engages the belt teeth, a smooth idler pulley is typically used on the non-toothed side of the belt. This makes it useful for return paths, belt redirects, tensioning assemblies, gantry layouts, and compact belt paths where the pulley does not need to transfer drive torque. A properly installed GT2 Smooth Idler Pulley helps reduce belt rubbing, uneven wear, poor tracking, and noisy motion.
GT2 timing belts have a toothed side and a smooth back side. This pulley is designed to contact the smooth side of the belt, helping guide the belt around a bend or tensioning point without engaging the belt teeth. The smooth 12mm outer belt contact diameter and 16mm flange outer diameter help guide the belt while supporting compact motion layouts.
This pulley includes a bearing for free-spinning idler use and has a 5mm inner bore. It can be mounted on compatible 5mm shafts, M5-compatible bolts, shoulder screws, spacers, or custom idler hardware depending on your build. Always confirm the shaft, screw, or axle arrangement before installation so the pulley spins freely without side binding.
The GT2 Smooth Idler Pulley supports GT2 belt systems up to 9mm wide, making it useful for machines that use wider belts than the common 6mm format. Wider belts can be used in printer and motion systems where additional belt width, durability, or design compatibility is required. Always verify your belt width, belt path, pulley clearance, and mounting hardware before final assembly.
This product is listed on dnb3D as a Rat Rig V-Core 3 specific part for the X gantry XY idler joint assembly and the XY drive assembly. The current product page also notes that V-Core 3.1 has moved toward flanged bearings, while idler pulleys remain an economical option that can still be used in some 3.1 upgrade builds. Always confirm your exact printer version, printed parts, and motion layout before ordering replacement hardware.
Beyond RatRig-style builds, this pulley can be used in CoreXY printers, Cartesian printers, CNC machines, laser engravers, robotics mechanisms, camera sliders, plotters, belt-driven fixtures, and automation projects. It is especially helpful in compact machines where belt routing must be controlled carefully and the pulley needs to guide the smooth side of a GT2 belt.
For related parts, browse the 3D Printer Parts category or the Fasteners category. This pulley can be paired with GT2 timing belts, metric socket head screws, bearings, spacers, washers, brackets, linear rails, guide blocks, smooth rods, and other motion hardware from dnb3D.
Timing belt systems commonly use both toothed pulleys and smooth idlers depending on whether the pulley contacts the toothed side or smooth back side of the belt. For general engineering context on synchronous timing belt systems, see this synchronous belt drive reference.
Every order is hand-inspected and precision-shipped from dnb3D in Marathon, Ontario. Whether you are repairing a RatRig-style printer, building a belt tensioner, assembling a CNC axis, or designing a custom motion system, this GT2 Smooth Idler Pulley provides a reliable belt-guiding solution for compact GT2 motion systems.
The GT2 Smooth Idler Pulley is designed to guide the smooth back side of compatible GT2 timing belts in 3D printers, CNC projects, robotics, and custom belt motion assemblies.
| Product Type | Smooth idler pulley / GT2 belt guide pulley |
|---|---|
| Belt System | GT2 synchronous timing belt systems |
| Tooth Pitch | 2mm |
| Number of Teeth | 0 — smooth idler pulley, not toothed |
| Belt Contact Surface | Smooth surface for the back side of the timing belt |
| Maximum Belt Width | 9mm |
| Inner Bore | 5mm |
| Bearing Included | Yes — integrated bearing for free-spinning idler use |
| Material | Aluminum alloy |
| Flange Outer Diameter | 16mm |
| Smooth Pulley Outer Diameter | 12mm |
| Overall Height | 13mm |
| Common Printer Fitment | Rat Rig V-Core 3 X gantry XY idler joint assembly and XY drive assembly; also useful for compatible DIY GT2 belt systems |
| Quantity Note | Rat Rig V-Core 3 style use commonly requires 2 pieces |
| SKU | DB-0057-5969 |
| Common Applications | 3D printers, CoreXY printers, CNC machines, robotics, laser engravers, plotters, camera sliders, belt tensioners, and DIY motion systems |
| Installation Style | Mounted as a free-spinning smooth idler or belt guide in a compatible GT2 belt path |
| Assembly Warning | Confirm belt width, 5mm bore fit, bearing clearance, pulley alignment, flange clearance, and mounting hardware before installation. Misalignment can cause belt wear, noise, rubbing, or poor motion quality. |
| Fulfillment | Hand-inspected and precision-shipped from dnb3D in Marathon, Ontario, Canada |
Before installing the GT2 Smooth Idler Pulley, confirm that the pulley is being used on the smooth back side of the GT2 timing belt. If your design requires toothed belt engagement or torque transfer, use a toothed GT2 timing pulley instead.
This pulley supports GT2 belts up to 9mm wide and uses a 5mm bore with an integrated bearing. Check that your shaft, bolt, spacer, shoulder screw, or axle hardware matches the pulley and allows the bearing to spin freely without side binding.
This pulley is commonly used as a Rat Rig V-Core 3 specific part for the X gantry XY idler joint assembly and XY drive assembly. The V-Core 3.1 update moved toward flanged bearings in some locations, so confirm your exact printer version, printed parts, and build documentation before ordering replacement hardware.
Proper alignment is important for smooth belt motion. The pulley should sit square to the belt path so the belt tracks evenly across the smooth surface. Misalignment can cause belt edge wear, noise, uneven tension, skipped motion, or rubbing against nearby parts.
When mounting the pulley, make sure spacers, washers, bolts, brackets, and printed parts do not rub against the rotating pulley, bearing, flange, or belt. The pulley should spin freely after installation with no side binding, wobble, or interference.
Use reasonable belt tension for your machine design. A belt that is too loose can skip or produce inaccurate motion, while a belt that is too tight can increase bearing load, create noise, wear the belt, or strain shafts, brackets, and printed parts.
After installation, rotate the pulley by hand and move the belt through the full travel path. The pulley should spin smoothly without grinding, binding, side rubbing, or visible wobble. Correct any alignment issues before running the machine at speed.
Keep the pulley and belt path free from dust, chips, filament debris, grease buildup, and abrasive particles. Contamination can reduce belt life and create rough or noisy motion. Inspect the pulley during regular printer or machine maintenance.
Every order is hand-inspected before shipping. dnb3D precision-ships pulleys, bearings, fasteners, and motion hardware across Canada from our Ontario facility, helping makers, builders, and machine owners receive clean, usable parts ready for careful installation.
At dnb3D, we don’t just ship boxes—we manufacture solutions. Operating our Industry 4.0 micro-factory in Marathon, Ontario, means your order is handled by the same people who design and test these components.
Ready to Ship (3D Printer Parts & Hardware): Finished, inspected, and on the shelf. Dispatched within 1 to 2 business days.
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Custom Projects: Bespoke designs require a consultation and a locked-in timeline before production begins.
We ship nationwide across Canada and the USA. Centrally located on the North Shore of Lake Superior, we are uniquely positioned to get your products moving quickly to either coast.
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