Industrial tyres and rims - Part 2: Pneumatic tyres (metric series) on 5 degrees tapered or flat base rims - Load ratings
1Key Takeaways
This document specifies the load ratings of the metric series of pneumatic tyres primarily intended for industrial vehicles for use on prepared surfaces. these tyres.
2Expert Interpretation
In-depth analysis of ISO 3739-2:2021 on the load rating standard for metric series industrial pneumatic tires with 5-degree tapered/flat-bottom rims, covering technical requirements such as reference load, dual-tire configuration rules and inflation pressure, which is suitable for the selection and design of industrial vehicles such as forklifts.
Analysis of the core content of the standard
The ISO 3739-2:2021 standard specifies a load capacity evaluation system under different working conditions for metric series industrial pneumatic tires with 5-degree tapered/flat-bottom rims. Compared with the 1992 edition, the new edition mainly expands the load data for large-size rims (diameter code>15).
Key Technical Parameters
| Vehicle Type | Speed Range(km/h) | Load Percentage | Applicable Wheel Position |
|---|---|---|---|
| Counterbalanced Forklift | ≤25 | 100%-130% | Steering Wheel/Load Wheel |
| Side Loader | Static | 151% | All Wheel Positions |
| Other Industrial Vehicles | ≤50 | 84%-130% | Depending on the axle position |
Key points for load calculation
Example calculation: A 10.00-20 A5 tire has a marked load index of 120 (corresponding to a reference load of 1500kg). When used for the steering wheel of a forklift with a speed of ≤25km/h:
Actual allowable load = 1500kg × 92.5% = 1387.5kg → rounded to 5kg to 1390kg
The total load capacity is doubled when dual tires are configured, but it is necessary to ensure that the rim meets the profile requirements specified in ISO 3739-3.
Inflation pressure specification
The standard specifies four reference inflation pressures (550/675/825/1000kPa), but the actual working pressure needs to be negotiated and determined based on factors such as vehicle type, speed level and ambient temperature. Special attention should be paid to the following:
- Cold tire pressure measurement should be carried out at ambient temperature
- Dynamic use needs to consider the pressure change caused by temperature rise
Implementation suggestions
1. Selection stage: Combine the size marking of ISO 3739-1 with the vehicle classification standard of ISO 5053-1
2. Load verification: For large-size tires with diameter codes of 24-33, they must be strictly tested according to the industrial cycle conditions in Table 4
3. Pressure monitoring: It is recommended to configure an intelligent tire pressure monitoring system (TPMS) to meet the pressure compensation requirements in different speed ranges