Your Ender 3 prints fine at 50mm/s but at 80mm/s the extruder starts clicking — the filament slips, the hobbed gear grinds a divot, and your print looks like a sponge. Single-gear extruders have one driven wheel and one idler bearing. When the idler slips, you get under-extrusion. A dual-gear extruder solves this with two driven gears that grip filament from both sides. Here’s the upgrade path, the real performance gains, and the pitfalls.
Step-by-Step Dual Gear Extruder Upgrade
1. Choose the Right Extruder for Your Printer
BMG Clone (sub-$20): The most common upgrade for Ender 3, CR-10, and similar Cartesian printers. 3:1 gear reduction, dual-drive hobbed gears. Works in Bowden or direct drive configuration. The genuine Bondtech BMG costs $80+; the Trianglelab clone at $25-35 is functionally identical — same gear ratio, same hardened steel drive gears, same housing geometry. I’ve run Trianglelab BMGs for 3,000+ print hours without a single extruder-related failure.
Bondtech LGX ($60-90): Larger drive gears for higher grip force. Designed for flexible filaments and high-flow hotends that need more push force. Overkill for PLA/PETG at normal speeds, but essential if you’re running a CHT nozzle or printing TPU above 60mm/s.
Orbiter V2.0 ($45-60): Ultra-lightweight direct drive extruder at 140g including motor. Uses a planetary gearbox instead of spur gears for 7.5:1 reduction. The best option if you’re converting to direct drive and weight matters — every gram on the X gantry reduces your maximum acceleration before ringing appears.
2. Installation and E-Step Calibration
- Remove the stock extruder assembly (4 bolts on Ender 3)
- Mount the dual-gear extruder in the same position for Bowden, or print a direct-drive mount for your hotend
- The motor direction may need reversing — BMG clones reverse the filament path relative to stock
- Calibrate E-steps: BMG clones typically need 400-420 steps/mm (stock is 93). Mark 120mm of filament, extrude 100mm, measure the remaining filament. If 27mm remains (you extruded 93mm instead of 100mm): new E-steps = (100 / 93) × current E-steps
- Store to EEPROM with M500
3. Tune Retraction Settings
Dual-gear extruders grip filament more positively, which means retractions are sharper and more effective. This lets you reduce retraction distance by 30-50% compared to stock:
- Bowden BMG: Start at 3mm retraction at 40mm/s (stock is typically 6mm at 25mm/s)
- Direct drive BMG: Start at 0.8mm retraction at 35mm/s (stock direct drive is 1.5-2mm)
- Orbiter direct drive: 0.4-0.6mm retraction at 30mm/s — the planetary gearbox has zero backlash, so retraction is nearly instantaneous
Test with a stringing tower (two thin pillars 20mm apart, printed in vase mode) before committing to a full print with the new settings.
4. Adjust Vref for the Extruder Motor
Dual-gear extruders with gear reduction require less motor current because the mechanical advantage amplifies torque. A BMG’s 3:1 reduction means the motor works one-third as hard for the same filament force. Reduce the extruder stepper Vref by 20-30% from stock to prevent the motor from running hot on long prints. If the stock Ender 3 extruder Vref is 0.72V, set it to 0.55-0.60V after the BMG upgrade.
Dual Gear Extruder Comparison
| Extruder | Gear Ratio | Weight (with motor) | Max Filament Force | Best For | Price Range |
|---|---|---|---|---|---|
| Stock Ender 3 (single gear) | 1:1 | 280g | ~3kg | PLA at <60mm/s | Included |
| Trianglelab BMG Clone | 3:1 | 310g (Bowden) | ~8kg | PLA/PETG/TPU at <100mm/s | $25-35 |
| Bondtech BMG Genuine | 3:1 | 310g (Bowden) | ~8kg | Same as clone, genuine warranty | $80-100 |
| Bondtech LGX | 3:1 | 260g (DD) | ~12kg | TPU >60mm/s, CHT nozzles | $60-90 |
| Orbiter V2.0 | 7.5:1 | 140g (DD) | ~6kg | Lightweight DD, high-speed printing | $45-60 |
Dual Gear Extruder Upgrade Mistakes
Mistake 1: Not Calibrating E-Steps After the Swap
The gear ratio changes from 1:1 (stock) to 3:1 (BMG) or 7.5:1 (Orbiter). If you don’t update E-steps, the printer will extrude one-third (or less) of the commanded filament. Your first print after the upgrade will be 70% air. As covered in our E-step calibration guide, every extruder change demands re-calibration.
Mistake 2: Running Stock Retraction Settings
Dual-gear extruders retract more effectively. Running stock retraction (6mm Bowden, 2mm direct drive) with a BMG causes heat creep — hot filament gets pulled too far into the cold zone, softens, and jams. Start at half your stock retraction distance and tune from there.
Mistake 3: Over-Tightening the Idler Tension Screw
Dual-gear extruders grip from both sides. The idler tension screw only needs enough pressure to prevent slippage — typically 1-2 turns past initial contact. Cranking it down deforms the filament from round to oval, which changes the effective diameter and causes inconsistent extrusion. A deformed filament also jams more easily in tight-tolerance heat breaks.
Mistake 4: Not Adjusting Linear/Pressure Advance
Dual-gear extruders have less filament compression under load because both sides grip evenly. If you previously tuned linear advance (Marlin) or pressure advance (Klipper) for a single-gear extruder, your values are too high. Reduce K-factor by 30-50% after the upgrade. As we explained in our under-extrusion troubleshooting guide, incorrect pressure advance produces exactly the same symptoms as mechanical under-extrusion.
⚠️ Safety Notice: Extruder upgrades involve working with electrical wiring and mechanical assembly. Always power off the printer before disconnecting or reconnecting stepper motor wiring. Incorrect Vref settings can cause stepper motor overheating — a hot extruder motor (>60°C) can soften PLA filament before it reaches the hotend, causing jams. If converting to direct drive, ensure the additional weight on the X gantry doesn’t cause sag — a sagging gantry produces uneven first layers and requires dual Z-axis stabilization.
The Trianglelab BMG V2 clone at $28 is the single best price-to-performance upgrade for any Ender 3. It ships with a hardened steel drive gear, a pre-assembled housing, and includes both Bowden and direct-drive mounting options. Available at uavmodel.com with pre-calibrated E-step values for stock Ender 3 motors.