Two polyurethane drive wheels can have the same size, color and Shore hardness but perform very differently in actual equipment. The reason is that polyurethane is not one fixed material. Its properties depend on the complete formulation and production process.
For forklifts, AGVs, pallet trucks and industrial transport vehicles, formulation can affect load capacity, traction, rolling resistance, wear, heat build-up, resistance to cutting and performance in water, oil or chemicals.
This guide explains how polyurethane drive wheel formulation affects industrial performance and what buyers should discuss with the wheel manufacturer.
Key point:
Polyurethane performance is created by the complete material system. The isocyanate, polyol, chain extender, hardness, additives, curing conditions and wheel design must be selected together. A single property such as Shore hardness cannot predict the complete performance of a drive wheel.
What Is a Polyurethane Formulation?
Cast polyurethane is produced by reacting an isocyanate component with a polyol and curing system. The selected ingredients and their proportions determine the structure and properties of the finished elastomer.
A drive wheel formulation may be adjusted to influence:
Shore hardness
Load-bearing performance
Rebound resilience
Rolling resistance
Abrasion resistance
Tear and cut resistance
Compression set
Hydrolysis resistance
Oil and chemical resistance
Electrical conductivity
1. Isocyanate System
MDI, NDI and other isocyanate systems can be used to produce cast polyurethane elastomers. Each system offers different formulation and processing options.
NDI-based systems are often evaluated for demanding dynamic applications involving repeated loading and heat. MDI-based polyurethane offers a broad range of hardness and performance options for standard and customized industrial wheels.
The isocyanate name alone does not determine whether a wheel is suitable. The complete formulation, wheel dimensions, load, speed and production quality must also be considered.
Read our detailed comparison of MDI vs NDI polyurethane drive wheels .
2. Polyester vs Polyether Polyol Systems
The selected polyol system has a significant effect on environmental resistance and mechanical performance.
| General Consideration | Polyester-Based Polyurethane | Polyether-Based Polyurethane |
|---|---|---|
| Mechanical strength | Often selected for strong abrasion and mechanical performance | Can provide useful resilience and flexibility |
| Oil resistance | Often provides useful resistance to oils and industrial fluids | Depends on the complete formulation |
| Water and humidity | Requires careful review for prolonged hot and humid exposure | Often considered where hydrolysis resistance is important |
| Dynamic applications | Suitable when formulation and wheel design match the duty | Can be selected for resilient and moisture-exposed applications |
These are general formulation tendencies. The finished wheel should be assessed using the actual temperature, water exposure, load and operating cycle.
3. Hardness
Hardness affects deformation, traction, load distribution and rolling resistance. A harder tread generally deforms less, while a softer tread generally provides more cushioning and floor contact.
Hardness is not the same as wear resistance or strength. Two wheels with the same Shore A value can have different:
Abrasion resistance
Tear strength
Rebound
Heat build-up
Compression set
Environmental resistance
See how polyurethane wheel hardness affects drive wheel performance .
4. Rebound Resilience and Rolling Resistance
As a drive wheel rotates, the tread compresses in the floor contact area and then returns to its original shape. Some energy is recovered and some becomes heat.
A formulation with suitable rebound can help reduce:
Internal heat generation
Rolling resistance
Motor current
Battery consumption
Fatigue during continuous operation
This is especially important for AGVs, AMRs and automated warehouse vehicles running long shifts.
For these applications, visit our warehouse automation and AGV wheel solutions .
5. Abrasion Resistance
Abrasion resistance affects how quickly the tread surface wears during repeated floor contact. It is important on forklifts, pallet trucks and AGVs that travel long distances each day.
Actual abrasion is also affected by:
Floor roughness
Wheel slip
Turning and side loading
Contamination and debris
Vehicle load
Operating temperature
A formulation with strong laboratory abrasion performance may still wear early if the vehicle skids frequently or runs over sharp metal debris.
6. Tear and Cut Resistance
Tear resistance is different from gradual abrasion. It determines how well the tread resists cuts, edge damage and chunking.
High tear resistance is particularly valuable for:
Rough concrete floors
Metal-processing plants
Mining and tunneling equipment
Vehicles making frequent tight turns
Routes containing sharp debris
For abrasive applications, see our mining equipment wheel solutions.
7. Compression Set
Compression set describes the tendency of the material to remain deformed after being compressed for a period of time.
Excessive compression set may lead to flat spots when equipment remains parked under load. The risk increases with high load, elevated temperature and long stationary periods.
Wheel diameter, tread thickness and formulation must be reviewed together where the equipment regularly remains parked with a heavy payload.
8. Heat Resistance and Internal Heat Generation
Drive wheel temperature comes from two sources:
External temperature from ovens, furnaces or the surrounding environment
Internal heat created by repeated tread deformation
A suitable polyurethane formulation should maintain its properties within the expected temperature range while controlling internal heat during operation.
Read more about drive wheel heat resistance .
9. Water and Hydrolysis Resistance
Water and high humidity can affect some polyurethane systems over time, particularly when exposure occurs at elevated temperatures.
Buyers should provide:
Normal humidity
Frequency of washdown
Water temperature
Immersion or splash conditions
Expected service period
A hydrolysis-resistant formulation may be required for food processing, cold storage, outdoor equipment and frequently washed production areas.
10. Oil and Chemical Resistance
Oil, hydraulic fluid, solvents and cleaning chemicals may cause swelling, softening or cracking if the polyurethane system is unsuitable.
Chemical resistance should be evaluated using the actual chemical name, concentration, exposure time and temperature. A general claim such as “oil resistant” is not enough for every industrial environment.
11. Conductive and Antistatic Additives
Selected industrial environments require control of electrical resistance. Conductive or antistatic additives can be introduced into the polyurethane system.
These additives may influence color and mechanical properties, so electrical requirements should be included during the initial material selection rather than added after the wheel design is complete.
12. Pigments and Non-Marking Formulations
Pigments and fillers can change more than appearance. They may affect hardness, conductivity, abrasion, heat absorption and floor marking.
A non-marking wheel should be evaluated for both floor cleanliness and required mechanical performance. Color alone does not guarantee that a tread will not leave visible marks.
Formulation Priorities by Application
| Application | Main Formulation Priorities |
|---|---|
| Electric forklift | Load, traction, abrasion, tear resistance and repeated braking |
| AGV or AMR | Low rolling resistance, stable diameter, low heat and low noise |
| Electric pallet truck | Concentrated load, turning wear and frequent start-stop operation |
| Mining transport equipment | Cut resistance, high torque, impact and strong tread bonding |
| Wet or humid environment | Hydrolysis resistance and reliable traction |
| High-temperature equipment | Temperature stability, load retention and controlled heat build-up |
What Information Is Needed for Formulation Selection?
Equipment type and application
Maximum dynamic load per wheel
Normal and maximum speed
Daily and continuous operating time
Floor condition
Required traction and rolling resistance
Temperature and humidity
Water, oil and chemical exposure
Non-marking or conductivity requirements
Current wheel material and failure problem
Custom Polyurethane Formulations from WSCS
WSCS manufactures industrial drive wheels for forklifts, AGVs, pallet trucks, warehouse systems and heavy machinery.
Our custom polyurethane wheel service can review tread formulation, hardness, wheel dimensions and metal-core structure as one complete system.
Send us the drawing or existing wheel sample together with the load, speed, duty cycle, floor and environment. Where required, different material options can be tested before volume production.
Frequently Asked Questions
Do all polyurethane drive wheels perform the same?
No. Polyurethane formulation, hardness, curing, tread geometry and manufacturing quality can produce significant performance differences.
Can Shore hardness identify the polyurethane formulation?
No. Different polyurethane systems can be produced at similar hardness levels. Hardness does not identify the isocyanate, polyol or complete formulation.
Which polyurethane is best for AGV drive wheels?
The formulation should balance rolling resistance, traction, heat build-up, dimensional stability, load and floor conditions.
Can a polyurethane formulation be customized?
Yes. Material selection can be adjusted according to load, speed, temperature, humidity, chemicals, conductivity and other application requirements.
