When engineers and buyers choose industrial wheels and rollers, they often know they want polyurethane—but they are not sure which الصلابة is best.
Pick a hardness that is too soft, and the wheel may deform, run hot and fail early.
Pick a hardness that is too hard, and you will get noise, vibration and premature wear on both the wheel and the floor.
In this guide, we explain how to choose the right polyurethane wheel hardness for conveyors, AGVs, forklifts and other material-handling equipment, so you can reduce downtime and get the longest possible service life.
1. What Does Polyurethane Wheel Hardness Mean?
Hardness is usually expressed in الشاطئ أ for polyurethane elastomers (for example, 70A, 80A, 90A, 95A, 98A).
- Lower Shore A (softer)
- More elastic and flexible
- Better shock absorption and quieter running
- More comfortable on uneven floors
- But: higher rolling resistance and more heat build-up
- Higher Shore A (harder)
- Higher load capacity
- Lower rolling resistance
- Better abrasion resistance on smooth floors
- But: less damping, more noise and vibration
Most industrial polyurethane wheels and rollers use hardness between 80A and 98A, depending on load, speed and floor conditions.
2. Key Factors That Decide the Right Hardness
Choosing the right hardness is not only about “soft or hard”. You must look at the whole application.
2.1 Load per Wheel
The first question is always: How much load does each wheel carry?
- Higher load → usually higher hardness to avoid excessive deformation
- Lower load → you may use slightly softer hardness for noise and comfort
If the load is near the maximum rating of the wheel, a wheel that is too soft will:
- Flatten at the contact patch
- Build up heat inside the polyurethane
- Age and crack much faster
For heavy AGVs, forklifts or pallet trucks, 92A–98A is common. For light trolleys and guiding wheels, 80A–90A can be enough.
2.2 Running Speed and Duty Cycle
Speed and duty cycle directly affect heat build-up inside the polyurethane.
Polyurethane is very good at handling dynamic loads—but if it runs too hot for too long, it will fail early.
- High speed + continuous running
- Needs higher hardness and good internal design
- Lower rolling resistance to reduce heat
- Example: high-speed AGVs in automated warehouses
- Low speed + intermittent use
- Can use slightly softer hardness if noise and comfort are important
- Example: manual push carts, low-speed conveyors
If you run a medium to heavy load at high speed with long duty cycles, 95A–98A polyurethane is usually safer.
2.3 Floor and Track Conditions
The condition of the floor has a big influence on comfort, noise and wear.
- Smooth, high-quality industrial floors
- You can use harder polyurethane (92A–98A)
- Rolling resistance is low, service life is long
- Rough concrete, expansion joints, outdoor areas
- Softer polyurethane (85A–92A) can reduce shock and noise
- Protects both the wheels and the floor
- Steel rails or tracks
- Often use harder grade with high cut and tear resistance
- Good bonding to steel core is critical
If noise is a concern—for example in warehouses near offices—slightly softer wheels can be a good compromise between comfort and durability.
2.4 Environment: Temperature, Chemicals, Humidity
Polyurethane performance changes with temperature and environment.
- Low temperature (cold rooms, freezers)
- Materials become harder and less elastic
- A “nominal” 90A may behave like a much harder wheel in deep cold
- Sometimes a slightly softer grade at room temperature performs better in service
- High temperature
- Accelerates aging and softening
- Need high-performance polyurethane formulation and correct hardness
- Chemicals, oils, water
- Special formulations may be required
- Hardness must be combined with the right polyol/isocyanate system and additives
Always tell your supplier the real working temperature range and any chemicals in contact with the wheels or rollers.
2.5 Noise, Vibration and Operator Comfort
If your factory cares about:
- Operator fatigue
- Noise levels
- Delicate goods that must not be shaken
… then you cannot simply choose the hardest wheel.
Softer polyurethane absorbs shock and vibration better, which is important for:
- AGVs delivering fragile goods
- Carts used on uneven floors
- Equipment operating near offices or labs
A typical compromise is:
- Driving / load wheels: 92A–95A
- Guide wheels / small rollers: 85A–92A
This combination offers good load capacity and damping where it is needed most.
3. Typical Hardness Ranges for Common Applications
The following table is a practical guide. Exact values can vary by formulation, wheel size and design, but it is a useful starting point.
3.1 Conveyor Wheels and Rollers
- Light duty conveyors (packaging, food cartons)
- 80A–90A
- Focus on quiet running and gentle handling
- Medium duty conveyors (logistics, warehouse)
- 90A–95A
- Balance between load, wear and noise
- Heavy duty conveyors (mining, steel, large pallets)
- 95A–98A
- High load, high abrasion, possible impact
3.2 AGV & Warehouse Robots
- Small AGVs / AMRs (light loads)
- 90A–95A
- Lower rolling resistance, acceptable comfort
- Heavy AGVs / tow tractors
- 95A–98A
- Strong load support and long life at continuous running
- Guiding wheels / side rollers
- 85A–92A
- Softer for reduced noise and better tracking
3.3 Forklifts, Pallet Trucks & Reach Trucks
- Drive wheels
- 92A–98A
- High load, frequent turning, high abrasion
- Load wheels & stabilizing rollers
- 92A–95A
- Must resist flat spots under static load
- Manual pallet jacks
- 90A–95A
- Good compromise between floor protection and rolling resistance
3.4 Special Applications
- Printing & paper industry rollers
- 80A–95A depending on nip pressure and function
- Surface finish is as important as hardness
- Mining and quarrying equipment
- 90A–98A with high cut and tear resistance
- Often combined with steel or cast-iron cores
If you are not sure, share your load, speed and environment data with your supplier and ask them to suggest a hardness range based on their past projects.
4. Why Polyurethane Wheel Design Matters as Much as Hardness
Hardness alone does not tell the full story. A good polyurethane wheel is a system:
- Core material
- Steel, cast iron, aluminum or plastic
- Affects load capacity and bonding quality
- Polyurethane formulation
- Different formulations at the same hardness can have very different
- قوة الشد
- Tear resistance
- Abrasion resistance
- Heat build-up behavior
- Different formulations at the same hardness can have very different
- Tread thickness and profile
- Thick treads can absorb more shock but may run hotter
- Tapered or crowned profiles can reduce edge wear
- Bonding technology
- Chemical treatment and primers ensure strong bonding between PU and the core
- Good bonding prevents tread separation under heavy loads
When you discuss a new wheel or roller, it is always better to talk about the whole design, not just hardness numbers.
5. How to Specify Your Polyurethane Wheel to a Supplier
To get a fast and accurate recommendation, prepare the following data:
- الأبعاد
- Outer diameter (OD)
- Width
- Bore size / core drawing
- Load and Speed
- Maximum load per wheel
- Typical running speed (m/s or km/h)
- Duty cycle (hours per day, stop/start, continuous or intermittent)
- Working Environment
- Floor type (epoxy, concrete, steel, outdoor)
- Temperature range
- Exposure to water, oil, chemicals, UV
- Performance Priorities
- Longest life / lowest downtime
- Quiet operation
- Floor protection
- Lowest rolling resistance
- Existing Problems (if replacing rubber or old wheels)
- Chunking, cracking, cutting
- Noise complaints
- Flat spots after long parking
- Bonding failure
With this information, an experienced polyurethane manufacturer can recommend:
- Proper hardness range
- Suitable polyurethane formulation
- Best core material and tread design
6. When to Choose Softer vs Harder Polyurethane
A simple decision framework:
Choose softer polyurethane (around 80A–90A) if:
- Noise and vibration are a serious concern
- The floor is rough or has many joints
- Loads are moderate and speed is low to medium
- You transport fragile goods that must be protected
Choose harder polyurethane (around 92A–98A) if:
- Load per wheel is high
- Speed and duty cycle are high (AGVs, conveyors running 24/7)
- Floors are smooth and well-maintained
- You want lowest possible rolling resistance and long wear life
In many projects, a combination works best—for example, harder drive wheels and slightly softer guiding or support rollers.
7. Need Help Choosing the Right Hardness?
Selecting the correct polyurethane wheel hardness is not guesswork—it is engineering. The most reliable way to get it right is to:
- Collect basic technical data for your application
- Share it with a polyurethane manufacturer that specializes in custom molded wheels and rollers
- Ask for a proposal including:
- Recommended hardness and formulation
- Expected load and speed ratings
- Sample lead time and testing plan
If you are upgrading from rubber or from an old wheel design, a well-designed polyurethane solution with the right hardness can:
- Double or triple service life
- Cut unplanned downtime
- Reduce noise and operator fatigue
- Protect your floors and equipment
Ready to specify your next polyurethane wheel or roller?
Prepare your drawing, loading data and working conditions, and send them to your supplier. A short discussion at the design stage can save many hours of troubleshooting later—and give you the ideal hardness for your conveyor or AGV fleet.