The Harmar Helix Custom Curved Stairlift: Mastering Mobility on Any Staircase

March 25 2025, by Richard Spafford, 8 min reading time

Unmatched Customization and Design: Built for Your Stairs

Precision Tailoring: A Perfect Fit for Every Curve

Custom Rail Design: Unlike straight stairlifts like the SL600, the Helix’s anodized aluminum rail is precision-bent to match your staircase—whether it’s a tight 90° turn, a sweeping 180° spiral, or a multi-flight layout with landings. Tracks extend up to 164 feet (50 m) across multiple floors, accommodating even the most elaborate designs (Harmar Technical Specs).
Slim Profile: Stands just 3 inches (7.6 cm) high and mounts 1-2 inches (2.5-5 cm) from the wall, preserving stair width. We’ve fitted Helix units on staircases as narrow as 30 inches (76 cm)—below the ADA’s 36-inch (91 cm) standard—where straight lifts simply can’t go.
Case Study: In a 1905 Victorian in Hartford, CT, a spiral staircase with a 32-inch radius and 12-foot rise stumped standard models. The Helix’s custom rail hugged the curve, its 13.5-inch (34.3 cm) folded width clearing a tight landing—avoiding a costly stair rebuild.

Compact Folding Mechanism: Space-Saving Elegance

Folded Dimensions: When parked, the Helix folds to 13.5 inches (34.3 cm) from the wall—seat up, armrests in, footrest raised—narrower than many curved competitors like the Stannah Siena (15 inches/38 cm) or Bruno Elite Curved (16 inches/40.6 cm). This keeps hallways and landings open.
Unfolded Footprint: Extends to 25 inches (63.5 cm) during use—still compact for active operation on tight curves.
Practical Clearance: Requires just a 14”x14” (35.6 x 35.6 cm) landing space, compared to 20-24 inches (50-61 cm) for bulkier models (Harmar Sell Sheet).

Robust Construction and Longevity: Engineered to Last

Weight Capacity and Structural Integrity

Capacity: Rated at 350 pounds (159 kg), the Helix supports a broad range of users—outpacing the Acorn 180 (265 lbs/120 kg) and matching the Bruno Elite Curved, but with a lighter footprint. Harmar’s dynamic load testing ensures stability on curves and swivels.
Materials:
- Rail: Aircraft-grade aluminum, anodized for rust resistance, withstands coastal salt air or basement humidity.
- Chassis: Powder-coated steel resists dents, paired with a UV-stabilized nylon polymer gear rack.
- Seat: Vinyl upholstery (beige standard) or optional fabric (gray, brown), reinforced with steel framing and 2-inch foam padding—built for daily wear.

Patented Drive System: Smooth and Maintenance-Free

Helical Worm Gear: Harmar’s patented drive (US Patent 7,360,816) uses a steel worm gear and nylon rack—no grease, no oil, no mess. Noise levels stay at 40-45 dBA, quieter than chain-driven lifts like the Acorn 180 (60 dBA) (Mobility Masters Data).
Lifespan: Rated for over 10,000 trips (10-15 years at 2 trips daily). Units we installed in 2018 still run flawlessly in 2025, thanks to the self-lubricating gear.
Torque: Delivers 50 Nm, powering inclines up to 60°—steeper than the SL600’s 52° max—without faltering.

Stress-Tested Durability

Environmental Resilience: The rail shrugs off New England’s freeze-thaw cycles (-20°F to 100°F/-29°C to 38°C with optional cold-weather kit), while the chassis endures minor impacts from canes or walkers—outlasting flimsier plastic frames.

Power Efficiency and Reliability: Ready When You Need It

Battery Performance: Outage-Proof Design

Power Source: Two 12V, 7Ah batteries (24V DC total) deliver up to 60 trips (30 up/down cycles) on a 20-foot (6 m) track during outages—double the Bruno Elite Curved (25 trips) and triple the Acorn 180 (20 trips). A 10-foot (3 m) cord connects to a 120-240 VAC charger.
Charging: Fully charges in 4-6 hours; trickle-charge prevents overcharging (Owner’s Manual, p. 4). An amber LED after 20 trips signals it’s time to recharge.
Cold Weather: Operates to 0°F (-18°C); an optional heater kit extends this to -20°F (-29°C)—key for unheated stairwells.

Energy Efficiency

Standby Draw: Just 0.5 amps (4 kWh/year), minimal impact on your electric bill.
Active Use: Peaks at 2.5 amps, gentle on household circuits.

Diagnostics: Smart and Simple

LED Codes: Green (normal), amber (low battery), red (service needed), with beeps (e.g., 2 beeps/second for off-charge). A diagnostic panel under the armrest reveals codes like “E2” for sensor faults (Owner’s Manual, p. 6).
Reset: Cycling the ON/OFF switch fixes 80% of minor glitches—like a bumped footrest triggering a sensor.

Seamless Accessibility and Safety: Comfort Meets Confidence

Ride Quality: Smooth and Steady

Speed: 20 feet per minute (6.1 m/min), adjustable to 18 fpm on steep curves. The helical gear ensures soft starts/stops—no jolts, unlike belt-driven lifts (e.g., Acorn 180).
Incline Range: Handles 27°-60°, tackling steep spirals or multi-flight stairs (average residential incline: 32°-38°).

Seat Comfort: Designed for You

Dimensions: 19”W x 16”D x 18”H (48 x 41 x 46 cm)—wider and taller than the SL300—offering lumbar support. Optional 21-inch (53 cm) seat or 3-inch padding suits larger users.
Swivel: Manual 85° swivel at landings (via lever); optional powered swivel (part #HELIX-PSW) eases dismounting.

Safety Suite: Comprehensive Protection

Obstruction Sensors: Five sensors (footrest and chassis) stop the lift in 0.5 seconds with a 3-beep alert—sensitive to small objects like a pet’s toy.
Swivel Interlock: Locks at 0° (riding) or 85° (dismount), preventing motion mid-swivel.
Seatbelt: Retractable 3-point harness (24-40 inches/61-101 cm), with optional 60-inch extension.
Overspeed Governor: Caps descent at 25 fpm, engaging a brake if exceeded.
Emergency Stop: Red armrest button halts motion instantly.
Key Lock: Optional (part #HELIX-KL) disables controls for safety.

Footrest: Stable and Spacious

Size: 12.3”W x 13.2”D (31 x 34 cm)—roomy for boots or braces—folds to 5 inches (12.7 cm) when parked.
Capacity: Supports 100 lbs (45 kg) direct pressure.

Installation and Operational Ease: Seamless Integration

Setup Process: Precision Craftsmanship

Mounting: Custom rail bolts to treads (5/16” lag bolts, 4-6 per 20-ft section) on stairs at least 30 inches (76 cm) wide. No wall drilling—just a solid tread base (1-inch thick minimum).
Time: 6-8 hours for a 20-ft (6 m) curve; 10-12 hours for multi-floor tracks. Tools: drill, level, inclinometer (e.g., Bosch GLM 20).
Site Specs: Needs 30-inch stair width, 14”x14” landing clearance, and 7-inch (18 cm) tread depth.

Controls: Intuitive Operation

Joystick: Weatherproof toggle (0.2 lbs force) on either armrest—ideal for limited dexterity. Hold to move; release to stop.
Remotes: Two infrared call/send units (50-ft/15 m range) with large buttons (0.75” diameter).
Indicators: Green (go), amber (charge), red (check)—status at a glance.

Portability: Future-Proof Flexibility

Disassembly: Unbolts in 6-8 hours with basic tools, reusable in a new home—unlike permanent curved lifts.

Aesthetic Integration: Blending with Your Home

Design Choices

Upholstery: Beige vinyl standard; optional gray or brown fabric. Custom colors available (2-3 week lead time).
Rail Finish: Satin silver aluminum complements wood, carpet, or tile—subtle yet modern.

Visual Harmony

Example: In a Boston brownstone, the Helix’s beige seat and silver rail blended with walnut stairs and cream walls, its 13.5-inch folded profile nearly invisible from the hall—unlike bulkier curved lifts disrupting the aesthetic.

The Critical Role of the Helix’s Design: Solving Real Challenges

Space and Safety Optimization

Curved Precision: Fits staircases straight lifts can’t touch—e.g., a 1920s spiral with a 10-foot rise and 90° landing, cleared without structural changes.
Clear Pathways: Folds to 13.5 inches, keeping tight landings accessible for walkers or wheelchairs.

Engineering Superiority

Grease-Free Drive: No maintenance hassles—outlasts greased systems prone to dust buildup.
Battery Edge: 60 trips in outages ensure access during storms—crucial for rural homes.

User-Centric Focus

Wider Seat: 19-inch (or 21-inch optional) width suits broader or taller users, enhancing long-term comfort.

Why We Champion the Helix: A Custom Triumph

After installing stairlifts from Harmar, Bruno, Acorn, and Stannah, the Helix shines for curved stairs. Its 350-lb capacity and 60-trip battery outpace the Acorn 180 (265 lbs, 20 trips), while its custom rail and grease-free drive surpass the Bruno Elite Curved for adaptability and upkeep. It turns winding, cramped staircases into safe, elegant routes—restoring independence with unmatched precision.

Technical Specifications: The Full Picture

Weight Capacity: 350 lbs (159 kg)
Speed: 20 fpm (6.1 m/min); adjustable to 18 fpm
Folded Width: 13.5 in (34.3 cm)
Track Length: Up to 164 ft (50 m) custom
Incline Range: 27°-60°
Seat: 19”W x 16”D x 18”H (48 x 41 x 46 cm); optional 21”W
Footrest: 12.3”W x 13.2”D (31 x 34 cm), 100 lbs capacity
Power: 24V DC (2 x 12V, 7Ah batteries), 120-240 VAC charger
Operating Range: 0°F to 100°F (-18°C to 38°C); cold-weather kit to -20°F (-29°C)
Safety Features: 5 sensors, 85° swivel interlock, 3-point seatbelt, overspeed governor, emergency stop, optional key lock
Weight: Unit: 95 lbs (43 kg); Rail: 5 lbs/ft (7.5 kg/m)

Contact USA Medical Supply Today

Unlock your home’s potential with the Harmar Helix Custom Curved Stairlift. Call 413-733-7843, text 413-200-4191, or visit 1779 Riverdale St, West Springfield, MA 01089. Our free in-home assessments tailor this world-class solution to your unique stairs—see why we’re passionate about its transformative power. Independence awaits—let’s make it yours!