| Load Capacity | Calculate the total equipment weight, payload, batteries, and safety margin. Divide the total load by the number of wheels that may carry weight during turning or uneven-floor conditions. | Light duty: up to 50 kg per wheel
Medium duty: 50–150 kg per wheel
Heavy duty: above 150 kg per wheel | Choose a wheel with a rated capacity comfortably above the calculated working load. A safety margin of approximately 25–50% is commonly used for dynamic movement. | Published load ratings may assume low speed, level floors, and evenly distributed weight. Shock loads, ramps, thresholds, and frequent starts can reduce practical capacity. |
| Wheel Diameter | Compare the wheel diameter with floor joints, small obstacles, thresholds, required platform height, and available installation space. | Small: 50–80 mm
General indoor use: 80–160 mm
Large or uneven-floor use: 160–250 mm+ | Larger wheels generally roll more easily over joints and debris, reduce rolling resistance, and provide smoother motion. Smaller wheels are useful where compact dimensions and low deck height are priorities. | Increasing diameter can raise the mounting height and may require a larger turning envelope or stronger frame clearance. |
| Wheel Width | Consider the required contact area, floor protection, traction, turning resistance, and available frame width. | Narrow: 20–35 mm
Standard: 35–60 mm
Wide: 60 mm+ | Wider wheels can distribute load more effectively and reduce contact pressure on delicate floors. Narrower wheels may reduce steering resistance and fit compact mechanisms. | Very wide wheels can increase scrub during rotation, especially on high-friction surfaces, and may require more drive torque. |
| Wheel Material | Match hardness, elasticity, chemical resistance, temperature resistance, and floor-protection requirements to the operating environment. | Polyurethane: balanced durability and floor protection
Nylon: hard, low rolling resistance
Rubber: quiet and vibration-absorbing
Steel: high-temperature or very heavy-duty environments | Polyurethane is a practical general-purpose choice for indoor industrial floors. Rubber is suitable where quiet operation and shock absorption matter. Nylon works well on clean, hard floors with higher load requirements. | Soft materials can increase rolling resistance and wear. Hard materials may be noisy, transmit vibration, or mark sensitive floors under high loads. |
| Roller Material | Evaluate the material of the small rollers that provide omni-directional movement, including wear resistance and resistance to impact. | Polyurethane or elastomer rollers: quieter and more floor-friendly
Nylon rollers: low resistance and good wear resistance
Metal rollers: high strength and temperature tolerance | Use resilient rollers for smooth indoor movement and lower noise. Use harder rollers where the floor is clean, rigid, and exposed to higher loads or temperatures. | Small rollers experience concentrated contact stress. Dirt, chips, and embedded debris can cause flat spots, jamming, or uneven movement. |
| Surface Compatibility | Assess floor hardness, smoothness, cleanliness, moisture, oil, chemicals, floor joints, and the risk of marking. | Smooth concrete or epoxy: most materials suitable
Tile or polished floors: resilient, non-marking materials preferred
Uneven floors: larger diameter and compliant rollers recommended | For clean, smooth indoor floors, polyurethane and rubber provide a good balance of traction and floor protection. For rough or contaminated floors, select larger wheels with durable, easy-to-clean materials. | Omni wheels are not ideal for deep gaps, loose gravel, soft soil, or floors with large steps. Debris can significantly affect roller movement. |
| Operating Speed | Check rated speed, acceleration, braking frequency, and the amount of time the wheel operates continuously. | Low speed: up to 1 m/s
Moderate speed: 1–2 m/s
Higher speed: above 2 m/s requires application-specific validation | For higher speeds, select a balanced wheel assembly with suitable bearings, secure roller retention, and an adequate dynamic load rating. | Actual speed capability depends on load, wheel diameter, roller design, surface condition, temperature, and drive control. Do not rely on load rating alone. |
| Bearing Type | Consider radial load, axial load, contamination, maintenance access, operating temperature, and required rolling resistance. | Plain bearing: simple and economical
Shielded ball bearing: low friction for clean environments
Sealed ball bearing: better protection against dust and moisture | Sealed bearings are generally preferable for mobile equipment exposed to dust, light moisture, or frequent cleaning. Plain bearings can suit slower, lower-cost applications. | Water, fine dust, chemicals, and poor alignment can shorten bearing life. Confirm bearing load ratings separately from the wheel load rating. |
| Floor Protection | Identify whether the floor is polished, painted, coated, tiled, or otherwise vulnerable to scratches, indentation, or black marks. | Highest protection: soft non-marking polyurethane or rubber
Balanced protection: medium-hard polyurethane
Lowest protection: hard nylon or metal on sensitive floors | Choose a non-marking compound and keep the contact pressure within the floor manufacturer's limits. Clean wheels regularly to prevent trapped particles from scratching the surface. | Even non-marking materials can damage floors when overloaded, contaminated, dragged laterally, or operated with locked rollers. |
| Environment and Temperature | Review ambient temperature, water exposure, oils, solvents, cleaning agents, dust, and potential corrosion. | Standard indoor: approximately 0–40°C
Special environments: select materials and seals for temperatures or chemicals outside this range | Use corrosion-resistant hardware and sealed bearings in humid areas. Confirm chemical compatibility before using polyurethane, rubber, nylon, or lubricants around solvents and cleaning agents. | Material temperature limits vary by formulation. Do not assume that a wheel suitable for dry indoor use is suitable for steam cleaning, ovens, acids, or aggressive solvents. |
| Mounting and Alignment | Verify mounting-hole pattern, shaft size, wheel-center height, frame stiffness, and parallel alignment of the wheel assemblies. | Common checks: mounting height, bolt spacing, axle diameter, clearance, and allowable angular misalignment | Maintain accurate alignment and a rigid mounting structure so that each wheel shares load and the rollers remain in consistent contact with the floor. | Misalignment can create uneven loading, vibration, premature bearing wear, increased motor current, and poor straight-line tracking. |
| Maintenance Requirements | Estimate inspection frequency, cleaning needs, replacement access, lubrication requirements, and spare-part availability. | Low maintenance: sealed bearings and contamination-resistant design
Routine maintenance: periodic cleaning, inspection, and bearing checks | Inspect rollers for flat spots, cracks, excessive play, embedded debris, and uneven wear. Replace damaged rollers before they affect the drive system or floor. | Maintenance intervals depend on duty cycle, contamination, load, speed, and surface condition. Use the manufacturer's technical limits for final scheduling. |
