Xingtai Valley Blue Technology Co., Ltd. | Comprehensive Guide to Selecting & Maintaining Rubber Power Transmission Belts
Intended Audience: Equipment engineers, procurement teams, after-sales, and end users
Product Coverage: Industrial/agricultural V-belts; automotive AV belts; poly-V (PK) belts; synchronous/timing belts (HTD/STD/GT/C14M); banded V-belts; variable-speed belts
1. What types of rubber belts are there?
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General/automotive V-belts (A/AV13, B/AV17, C/AV22 …): Highly versatile and cost-effective; used on fans, pumps, compressors, etc.
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Narrow V-belts (SPZ/SPA/SPB/SPC): Higher power density; suitable for compact, high-load drives.
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Banded belts (AA/BB/3V×n/3-SPB×n): Multiple ribs joined; resist turnover and shock; very stable.
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Poly-V belts (PJ/PK/PL/PM): Thin, flexible, low noise; common for engine auxiliaries and home appliances.
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Timing belts (MXL/XL/L, 3M/5M/8M/14M, C14M): Positive engagement with no phase slip; used for positioning and synchronization.
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Special belts: Hexagonal belts, variable-speed belts, harvester belts, etc.
2. How to select quickly? (5-step method)
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Define duty: power/torque, speed, load fluctuation, start/stop frequency.
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Environment: temperature, dust, oil, chemicals, space limits & minimum pulley diameter.
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Material choice: CR / EPDM / HNBR (see next section).
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Size & reference: confirm belt section and length base (Li/Lw/La).
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Safety factor: verify to standards and experience (poly-V/timing belts: check minimum teeth and wrap angle).
3. Materials & cord comparison
Material | Typical Temp. Range | Advantages | Typical Applications |
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CR (Chloroprene) | –30 to +90 °C | Balanced performance, moderate cost | General industrial/agricultural, normal temps |
EPDM | –40 to +120 °C | Excellent heat, ozone & aging resistance | Engine bays, high-temperature outdoor |
HNBR | –30 to +140 °C | High heat/oil resistance, fatigue strength | High temp & load, long service life |
Cords: Polyester / Fiberglass / Aramid | — | Aramid: high strength, low stretch; Fiberglass: heat resistant | Shock load, long centers, timing belts |
We can supply CR/EPDM/HNBR compounds, with polyester/fiberglass/aramid cords; OEM/ODM available.
4. Sizing & marking rules (common conversions)
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B section (17 mm):
Li = Lw – 43
,La = Li + 69
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C section (22 mm):
Li = Lw – 56
,La = Li + 88
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SPB (narrow V):
Lw = Li + 60
,La = Li + 88
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AV13 (automotive): approx.
Lw = Li + 36
,La = Li + 51
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PK rib count:
ribs ≈ belt width ÷ 3.56 (mm)
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Timing belt teeth:
teeth = pitch length ÷ pitch
(e.g., C14M-2800 → 200 teeth)
Example: AV13×813 Li → Lw ≈ 849, La ≈ 864 (mm).
5. Service life & storage
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Normal duty life: CR V-belts/timing belts ~ 10,000–15,000 h; EPDM typically longer.
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Storage life (unused): CR ~3–5 years; EPDM/HNBR 8–10 years (0–30 °C, RH < 70%, avoid light/ozone, store flat or hanging, no folding).
6. Installation tension & maintenance tips
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Initial retension: After installation, run no-load for 5–10 min, then retension.
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Deflection check: About 1.5% of span as a reference; force per manual/experience tables.
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Alignment: Sheaves in one plane and coaxial; aim for wrap ≥ 120° (timing belts: mind min teeth & wrap).
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Inspection: Every 500–1000 h check tension, tracking, cracks, edge wear, and oil contamination.
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Replace in sets: Multiple belts must be same batch/length class; for timing belts, inspect pulleys too.
7. Common faults & diagnostics
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Slip/overheat: Insufficient tension, pulley too small, or overload → retension / recalc power.
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Edge wear/debris: Groove wear or misalignment → correct alignment, verify groove angle.
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Early cracking: Excess heat, oil/chemicals → choose EPDM/HNBR and add protection.
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Timing belt tooth loss: Poor meshing, insufficient teeth/wrap, low tension → change pulley size or add idler.
8. Typical cases (brief)
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Agriculture: Kubota SB/SC replacement belts — EPDM compound + aramid cords, resistant to dust/mud & high temperature.
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Industrial fans: Upgrade from B/SPA to SPB → 20–30% more power capacity and more stable tension.
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Synchronous positioning: Upgrade from 8M to C14M → higher capacity at the same wrap, quieter operation.
9. About Us
Xingtai Valley Blue Technology Co., Ltd.
Specialized in R&D and manufacturing of industrial/agricultural rubber power transmission belts, automotive poly-V and timing belts.
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Standards: ISO 4184 / DIN 2215 / ISO 1813
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Capabilities: Mixing → calendering → vulcanization → on-line cord tension control → 100% visual & dimensional inspection
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Services: Fast sampling, OEM/ODM, branded packaging, global shipping