Guide · Mechanical upgrades
Extruder upgrades: gear ratio, dual gears and feeding force
What a new extruder changes: gear ratios makers state, hardened vs clone gears, one measured force comparison, and when the stock extruder is not the problem.
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Short answer
An extruder upgrade changes three things: how firmly the gears grip the filament, how much the motor is geared down, and how tightly the filament path guides the strand. It helps when the extruder is the weak link. Check that first, because uneven extrusion often has another cause, and every new extruder needs new E-steps.
What an extruder upgrade changes
An extruder pushes filament into the hotend. A dual-gear extruder grips the strand from both sides instead of pressing it against an idler bearing. A geared extruder puts a reduction between the motor and the drive gears, so the motor turns more for each millimeter of filament.
A swap can also move the extruder onto the print head. That is a direct drive conversion, as opposed to a Bowden setup where a tube carries the filament from a frame-mounted extruder.
Gear ratios the makers state
Each maker states its own reduction. The numbers are not comparable on their own, because gear sizes and motors differ.
| Extruder | Stated reduction | Source |
|---|---|---|
| Bondtech BMG and BMG-based | 3:1 | Bondtech FAQ[1] |
| Micro Swiss NG direct drive | 3:1, hardened steel dual gears, LDO motor included | Micro Swiss[2] |
| ELEGOO Neptune 4 Plus stock | 5.2:1 dual-gear direct | ELEGOO[3] |
| Sovol SV06 ACE stock | 1:7.5 planetary dual-gear | Sovol[4] |
The gear ratio matters to your firmware. A different ratio means a different number of motor steps per millimeter of filament, so the old E-steps value no longer applies. Bondtech's LGX product page gives no ratio at all, and the LGX takes 1.75 mm filament only.[5]
Hardened gears and clones
Bondtech says its BMG primary drive gear is heat-treated and nickel-coated. It examined one clone and reports that its gears were not hardened.[6] That finding covers one unit and comes from the original maker, so read it as a reason to check what you are buying, not as proof about every clone.
Micro Swiss lists hardened steel drive gears on its NG extruder.[2]
Feeding force: one measured setup
CNC Kitchen measured feeding force in 2023 by pushing filament into a hotend on a load cell. The stock Ender-3 feeder pushed about 2.8 kg. The other extruders in that comparison ranged from about 4 to 10 kg at normal settings.[7] Some results used motor currents above recommended levels, and force does not measure print quality.
Annex Engineering publishes a force chart too, but it is a calculated comparison built from motor torque curves, gear ratios and estimated gear sizes, not a physical measurement. It calls the BMG and LGX comparable.[8] Do not rank extruders by it.
The filament channel and jams
The path between the gears and the hotend matters as much as the grip. Bondtech says its 1.75 mm extruders have a 2.0 mm filament channel, so an oversized section of filament can jam and be ground by the gears.[9] A tighter guide controls the strand better, but it is less forgiving of filament that is out of round.
When not to buy one
Rule out the simple causes first: a partial clog, wrong temperature, a slipping idler or bad filament. CNC Kitchen once traced uneven layers on a Cetus MK3 to a drive gear whose bore was off-center.[10] It did not establish how common that is, and it suggests checking gears only after other causes are ruled out.
Fit is per model. Micro Swiss sells a separate NG kit for the Ender 3 V2 Neo (M3208), apart from the M3201 kit for the CR-10 and Ender 3 family, so a V2 kit is not a Neo kit.[11] If you are not sure which printer you have, start with identifying your exact model and revision.
Picks that fit2 products
Only for a Creality Ender 3, Ender 3 Pro, Ender 3 V2 or the CR-10, CR-10s, CR-10-S4 or CR-10-S5.
More on choosing
Choose the NG (M3201) to keep MK8-style nozzles, or the NG REVO 24 V (M3301) for E3D Revo nozzles. The Ender 3 V2 Neo needs a different kit. On Amazon, check that 'Ships from / Sold by' shows Amazon.com or Micro Swiss.
Choose the NG to keep a conventional all-metal hotend
Micro Swiss NG direct drive extruder for Creality CR‑10 / Ender 3 (M3201)
Choose the NG REVO for tool-free Revo nozzle changes
Micro Swiss NG REVO direct drive extruder for Creality CR‑10 / Ender 3, 24 V (M3301)
Next
Questions
Does a dual-gear extruder push harder than a single-gear one?
In CNC Kitchen's 2023 load-cell comparison, the stock Ender-3 feeder pushed about 2.8 kg while the other extruders in that comparison ranged from about 4 to 10 kg. That is one setup, and force is not a measure of print quality.[7]
Is a clone BMG the same as a Bondtech BMG?
Not necessarily. Bondtech says its BMG drive gear is heat-treated and nickel-coated, and reports that one clone it examined had unhardened gears. That is a single unit examined by an interested party, so it does not describe every clone.[6]
Do I need to change firmware after an extruder swap?
Usually you change the E-steps or rotation distance, because the gearing changes. Bondtech publishes 415 E-steps for the BMG at 16 microsteps; Micro Swiss offers a G-code download for the NG instead of a number. See E-steps and rotation distance.[1][2]
Does a Micro Swiss NG kit for the Ender 3 V2 fit the Ender 3 V2 Neo?
No. Micro Swiss sells a separate NG kit for the Ender 3 V2 Neo (M3208), apart from the M3201 kit for the CR-10 and Ender 3 family.[11]
Is the Annex Engineering force chart a measurement?
No. It calculates force from motor torque curves, gear ratios and estimated gear sizes, and calls the BMG and LGX comparable. It is a calculated comparison, so we do not rank extruders by it.[8]