Description
Otis Door Hanger Roller 85mm*20mm-6204Z DAA456N2 Brief introduction
| Otis Door Hanger Roller | |
| Brand | Original |
| Model | 85mm*20mm-6204Z |
| Goods No. | DAA456N2 |
| MOQ | 1 |
| Warranty Time | 1 year |
| Certificates | ISO9001 |
| Brand | Xizi Otis LG SIGMA |
Otis Door Hanger Roller 85×20×6204Z – The 85 mm Silent Wheel That Keeps Every Door Gliding
Courtesy of Nanjing Zhuye Elevator Parts Co., Ltd.
Courtesy of Nanjing Zhuye Elevator Parts Co., Ltd.
Every time you hear the soft “whoosh” of an Otis elevator door, you’re actually listening to a hardened-steel wheel spinning silently above the header — the 85×20×6204Z door hanger roller. Measuring 85 mm diameter × 20 mm tread × 6204Z sealed bearing, this factory-balanced wheel carries the full weight of the door panel while reducing motor torque by 30 %. Nanjing Zhuye Elevator Parts keeps factory-sealed rollers in anti-static stock for next-day despatch. Below we explain what the roller does, how to install it in under 15 minutes, and the replacement cycle that prevents expensive “door heavy” call-backs.
1. What 85×20×6204Z Really Is
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Dimensions: 85 mm OD × 20 mm tread × 17 mm bore (6204Z sealed bearing)
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Material: 65Mn steel rim, zinc-nickel 8 µm, salt-spray 96 h
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Bearing: 6204Z, Z2 noise grade, grease-filled -30 °C to +80 °C
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Load: 3.8 kN static, 1.9 kN dynamic — suits doors up to 120 kg per panel
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Balance: factory-balanced to ±0.5 g — eliminates vibration at 2.5 m/s door speed
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Pack Unit: 1 roller + 2 circlips + M12 shoulder bolt + 2 mm Allen key
The roller slides on the header rail, carries the full door weight and regenerates 15 % of kinetic energy back into the operator.
2. Where It Is Used
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Otis Gen2-R2®, SkyRise®, Xizi super-MRL 1.75–4.0 m s⁻¹
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Thyssen TCM-MC3 retrofits using Otis hanger geometry
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Machine-room-less (MRL) or machine-room (MR) centre-opening doors
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New build or modernisation — one part number fits any 85 mm header
3. Installation – 15-Minute Retrofit
Safety: place lift on inspection, lock main breaker, tag out, prop door to 50 % open.
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Remove old roller — undo M12 shoulder bolt; slide worn roller off hanger arm.
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Inspect rail — if scoring >0.2 mm, polish with 600-grit emery or replace rail.
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Insert new roller — push until circlip seats; ensure 0.05 mm preload on rail.
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Tighten bolt — torque 55 N·m; check roller spins freely with <5 N pull force.
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Run 5 cycles — measure motor current; verify <70 % of name-plate value.
No special tools beyond Allen key and torque wrench — follow EN 81-20.
4. Daily Operation – What the Roller Actually Does
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Carries 100 % of door panel weight; safety factor ≥8 (EN 81-20)
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Transmits motor torque without slip; 1:1 or 2:1 roping ratio
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Factory grease releases micro-film, preventing rail corrosion
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Pre-balanced eliminates vibration at 2.5 m/s door speed
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Temperature range -30 °C to +80 °C — outdoor scenic lifts included
5. Replacement Cycle & Preventive Maintenance
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High-traffic office (>1,500 cycles day⁻¹) – inspect every 6 months, replace rollers every 4 years
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Residential tower (300–600 cycles day⁻¹) – inspect annually, replace every 6 years
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Low-rise freight (≤200 cycles day⁻¹) – inspect every 18 months, replace every 8 years
Replace immediately if:
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Diameter worn >2 % (caliper test)
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Radial play >0.3 mm when 50 N side-load is applied
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Bearing noise >65 dB(A) at 1 m during run
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Zinc flaking >10 mm² or corrosion pits >0.1 mm
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Hand force >100 N at mid-travel
6. Extending Life – 3 Pro Tips
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Keep rail straight; 2 mm dent halves roller life
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Clean rail monthly; brake-dust paste acts like grinding paste
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Never grease—zinc-nickel plating is self-lubricating; excess attracts grit
7. Why Buy 85×20×6204Z from Nanjing Zhuye Elevator Parts?
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Factory-new 65Mn, not recycled steel; passes 3-million-cycle wear test
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Zinc-nickel plated 8 µm; salt-spray 96 h — no rust in coastal shafts
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Dual stock: 8,000 pcs Nanjing, 2,500 pcs Dubai — next-day to 65 countries
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Bundle kit: roller + circlips + M12 bolt + 2 mm Allen key — 5 % cheaper than single OEM piece
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24 months warranty against cracking or abnormal wear
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7×24 WhatsApp/WeChat video support; average response 10 minutes
Conclusion
The Otis Door Hanger Roller 85×20×6204Z is the unseen wheel that carries tonnes of door weight every day — yet never asks for attention until it squeaks. Stock a handful from Nanjing Zhuye on every service truck, swap them on schedule, and replace “door heavy” complaints with a fifteen-minute planned fix — one balanced, silent entrance at a time.
