Right Angle Hypoid Speed Reducers
A high-efficiency, long-life alternative to traditional worm-gear reducers. Hypoid gearing — where mating teeth roll rather than slide — delivers higher torque density, lower heat generation, and dramatically longer service life in the same compact 90-degree footprint.
Download KM Series catalog
Why hypoid replaces worm.
90–98% efficiency
Rolling-contact hypoid teeth versus the 35–90% sliding-friction range of worm gearboxes.
Low heat generation
Minimal energy is lost as friction heat, so the gearbox runs cooler and the surrounding system stays in spec.
20,000+ hour service life
Roughly twice the typical service life of an equivalent worm-gear unit, with backlash that stays consistent over time.
High torque density
Multiple teeth in contact at once let the unit transmit higher torque from the same compact envelope.
Fully reversible
No worm-style self-locking limitation — the unit drives cleanly in either direction.
NEMA-compatible inputs
56C / 140TC / 180TC / 210TC input flanges drop directly onto standard North American motors.
Side-by-side comparison.
| Parameter | SIEGMA KM Hypoid | Worm Gear Reducer |
|---|---|---|
| Tooth contact | Rolling (low wear) | Sliding (high wear) |
| Typical efficiency | 90–98% | 35–90% |
| Heat generation | Low | High |
| Service life (typical) | 20,000+ hours | 10,000–15,000 hours |
| Backlash over time | Stays low and consistent | Increases as bronze wheel wears |
| Reversibility | Fully reversible | Often self-locking |
| Torque density | High (multi-tooth contact) | Moderate |
KM Series at a glance.
General specifications
Range and ratings shared across the KM family.
| Frame sizes | KM050, KM063, KM075, KM090, KM110 |
|---|---|
| Gear stages | 2-stage (B) and 3-stage (C) |
| Typical efficiency | 90–98% |
| Typical service life | 20,000+ hours |
| Ratio range (2-stage) | ~7.48:1 to 60.5:1 |
| Hollow output bore | 1.00″ (KM050) · 1-3/16″ (KM063 / KM075) · 1-7/16″ (KM090) |
| Input flange options | 56C, 140TC, 180TC, 210TC |
| Output flange options | FAL, FBL, FCL, FDL, FEL, FAR, FBR, FCR, FDR, FER (or XX = none) |
| Mounting accessories | Torque arm left (TAL) · torque arm right (TAR) |
| Output shaft styles | Hollow bore (HB) or solid output left/right (SSL/SSR), customer-specified diameter |
Available 2-stage ratios by frame
Pre-configured ratio set per frame size, from the catalog selection tables.
| Frame | Available ratios (2-stage) |
|---|---|
| KM050B | 7.73, 10.47, 12.47, 14.92, 20.21, 24.07, 29.33, 48.96, 58.36 |
| KM063B | 7.6, 10.5, 12.67, 14.67, 20.25, 24.44, 30.31, 39.29, 48.71, 60.5 |
| KM075B | 7.48, 9.84, 12.49, 15.09, 19.84, 25.19, 30.24, 40.13, 48.18, 59.44 |
| KM090B | 7.48, 9.84, 12.49, 15.09, 19.84, 25.19, 30.24, 40.13, 48.18, 59.04 |
KM110 is referenced in the model size list but no specific KM110 ratio table appears in the current published catalog. 3-stage (C) variants are available on request — ratio sets are not listed in the current catalog tables.
Hypoid vs. worm cross-section
Reference diagram
Model number breakdown.
Each KM part number encodes seven configuration positions. Example: KM 063 B 20.25 XX HB1.1875 56C
| Position | Field | Options |
|---|---|---|
| 1 | Series | KM (right-angle hypoid) |
| 2 | Size | 050, 063, 075, 090, 110 |
| 3 | Stages | B (2 stages), C (3 stages) |
| 4 | Ratio | Numerical reduction ratio (e.g. 20.25) |
| 5 | Output flange | XX (none), FAL/FBL/FCL/FDL/FEL, FAR/FBR/FCR/FDR/FER, or torque arm TAL/TAR |
| 6 | Output shaft | HB<d> hollow bore (e.g. HB1.1875), SSL/SSR<d> solid output (e.g. SSL1.00) |
| 7 | Input | 56C, 140TC, 180TC, 210TC, or shaft input |
Where the KM series fits.
Suited to material handling, conveyors, packaging machinery, mixers, food and beverage processing, automated assembly equipment, and other industrial drive applications where a worm gearbox would traditionally be used — but where higher efficiency, cooler operation, lower energy consumption, or extended service life is desired.
- Material handling
- Conveyor drives
- Packaging machinery
- Mixers & agitators
- Food & beverage
- Automated assembly
- Worm reducer replacements
KM series imagery.
KM Series — Full catalog
Six-page catalog with the hypoid-vs-worm comparison, full nomenclature breakdown, and the complete ratio selection tables for KM050B through KM090B.