03Sep 2025

How to Choose Industrial Casters: Color, Use, and Wheel Diameter

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In a wide range of applications, casters are far from simple parts. They may look like “just wheels,” but they directly impact load capacity, safety, noise, and operational efficiency. Wheel diameter, contact area (footprint), tread material, and durometer all influence rolling resistance, maneuverability and swivel smoothness, as well as floor protection. Most importantly, color is seldom cosmetic; it often serves as a management code that indicates the material, hardness, or intended application.

I. Color = Intuitive Layers of Material & Use (HICKWALL Casters – Color Coding in Practice)

Color is a visual identifier, not a quality ranking. Real-world performance is defined by compound, durometer (hardness), construction, and manufacturing process. Different brands may use different color schemas; the mapping below reflects common practice.

1. Gray / Black Wheels

Typical materials: Rubber / synthetic rubber (also available in conductive compounds)
Key traits: Shock absorption, low noise, good traction, floor friendly. Suited to general use and surfaces that need cushioning.

Suitable environments & industries

Factory / warehouse in-plant logistics: Joints and aggregate/terrazzo surfaces; quieter rolling.
Low-noise areas: Hospitals, clinics, schools, libraries, offices.
Service & public venues: Hotels, department stores, museums, exhibition halls; non-marking rubber available.
Precision equipment / metrology & EMS: Vibration damping and floor protection; where ESD control is required, use conductive/ESD rubber.
Foodservice / medical carts & indoor routes: Flat floors (epoxy, PVC, tile); better slip resistance and cushioning over thresholds and ramps.

Notes：If you need conductive/ESD, select by resistance spec, not by color.　For heavy loads + long distances / higher speeds, or where floors have oil or metal chips, consider PU or other materials first.

2. Blue / Green / Yellow Wheels

Typical material: Polyurethane (PU) (also available in anti-static/ESD compounds)
Key traits: High wear resistance, high load capacity, tunable durometer, low rolling resistance, quiet running. Broad applicability; the mainstream choice for logistics and production.

Suitable environments & industries

Warehousing / 3PL / e-commerce: Long runs with lower effort; friendly to epoxy/PVC floors.
Production lines (machining, sheet metal, injection molding): Resistant to oils and most coolants; supports medium-to-high loads.
AGV / AMR material handling: Low rolling resistance and energy use; on-site color = hardness coding for maintenance.
Electronics / semiconductor / EMS: Choose ESD-rated PU to reduce static risk; runs quieter.
Medical / labs / offices & exhibitions: Quiet indoors and floor protection; non-marking options available.
Food / beverage / packaging: Durable and low-effort; verify food-grade formulations when needed.
Cold chain / freezers: Use low-temperature PU to maintain elasticity and grip.

Notes：Floors with metal chips or sharp debris: increase hardness, use a thicker tread, or add guards.　　Heavy loads parked for long periods can cause flat-spotting; use jacks/blocks during idle time.　　Sustained high temperature: use heat-resistant PU formulations or other high-temp materials.　　For ESD, select by resistance spec; color is only an identifier.

3. White Wheels

Typical materials: Nylon / PP (polypropylene)
Key traits: High hardness, low rolling resistance, chemical resistance, moisture resistance; white surfaces make hygiene checks easier.

Suitable environments & industries

Food processing & packaging; central/commercial kitchens: Resistant to detergents and sanitizers; suitable for long, wet routes.
Cold chain / cold storage & freezers: Low water absorption; choose low-temperature grades for sub-zero use.
Laboratories / pharma (non-ESD) & wash lines: Compatible with many chemicals (verify chemical compatibility for your agents).
Seafood / wet operations: Pair with stainless-steel rigs.
High-load, low-speed on flat hard floors: Nylon offers high capacity and efficiency (e.g., epoxy floors).

Notes：Harder and noisier; less floor-forgiving: If floors scratch easily or noise is a concern, switch to medium-durometer PU, wider tread, or non-marking compounds.　　PP typically has lower load/heat limits than nylon: Prefer PP for light/medium loads; choose nylon for higher loads.　　Where ESD is required, avoid standard white nylon/PP and use materials with verified electrical specs.

4. Red / Orange / Dark Blue Wheels

Typical materials: High-performance PU or high-temperature materials (ESD versions available)
Key traits: Built for high load / high duty cycle / elevated temperature. Low rolling resistance, minimal deformation.

Suitable environments & industries

Heavy tooling carts / tuggers: Long runs at higher loads/speeds; high-strength/high-durometer PU plus premium bearings reduces effort.
Coils, plate, heavy fixtures: Sharp edges and impacts; use higher-durometer PU, thicker treads, and guards.
Machining & sheet-metal shop logistics: Handles chips and burrs better; stable wear life and performance.
Paint / curing lines & oven perimeters: Intermittent or continuous heat requires heat-resistant grades; beyond PU limits, switch to phenolic/metal wheels.
Electronics / semiconductor (ESD zones): Under heavy loads and long runs, use ESD/Conductive high-performance PU.

Notes：For continuous heat, confirm the actual temperature window; if it exceeds PU limits, use true high-temp materials.　　ESD selection is based on measured resistance, not color.　　With chips/sharp debris, increase durometer, use thicker treads or guards, and improve floor housekeeping.　　For heavy loads parked long, plan for jacking/blocks to reduce flat-spot risk.

Quick FAQ

Q1. Does a darker color mean better durability or higher load?

No. Color mainly identifies material or hardness tiers. Durability and capacity depend on compound, durometer, design, and process.

Q2. What’s the difference between anti-static and conductive?

Both manage static electricity; they differ in resistance ranges and control levels. Select according to your customer/industry spec and test data, not color.

Q3. Are rubber wheels always quieter than PU?

On most floors at comparable load/speed, rubber offers better damping and feels quieter. However, PU is tunable; many medium-durometer PUs balance quiet running with wear life.

II. Wheel Diameter: The Key to Effort, Obstacle-Crossing, Floor Care, and Noise

1. Why do larger wheels push easier?
Bigger wheels are less affected by joints, small pits, and debris, so rolling resistance drops. Starts feel lighter and long pushes are less tiring. For powered tow, that also means lower energy use and longer runtime.

2. Obstacle-crossing: use the “threshold rule”
Field rule of thumb: threshold height ≤ 8–12% of wheel diameter for smooth passage.
Example: with a 12 mm threshold, choose 100–150 mm (4"–6") wheels. If your route has frequent joints or rougher texture, step up one size for stability.

3. Diameter vs. floor protection and noise
Larger diameter increases the contact arc and reduces contact pressure, which is gentler on epoxy/PVC floors and reduces high-frequency bumping—quieter overall.
Tip: If you want fewer wheel marks and lower noise, increase diameter and tread width one step; the difference is noticeable.

4. Bigger isn’t always better
Larger wheels typically raise overall equipment height and cost, and may impact turning radius and space (e.g., swivel offset and swivel head/top-plate diameter). Balance ease/floor care against height/cost; avoid upsizing if you have strict height or clearance limits.

5. Recommended diameter ranges (in / mm, pre-selection reference)
(rounded to common market sizes)

3"–4" (≈75–100 mm): Short runs, light loads; quiet, floor-friendly indoor carts.
4"–5" (≈100–125 mm): Factory/warehouse general purpose; balance of quiet, effort, and cost.
5"–6" (≈125–160 mm): Medium runs and loads; better over joints, less “catching.”
6"–8" (≈160–200 mm): Better obstacle-crossing; suits varied floors and higher duty cycles.
≥8" (≥200 mm): Heavy load + long distance / towing; superior bump compliance and rolling control.

6. Pair diameter with the right hardware

Bearings: For long runs and heavier loads, choose high-grade ball bearings or roller bearings to cut rolling drag.
Protection: In dusty or humid areas, specify dust caps and double-lip seals to extend bearing life.
Rig strength: Larger diameters demand stiffer rigs—upgrade plate thickness, yoke spacing, and swivel head/top-plate diameter; don’t swap wheels without checking the rig.
Space: When upsizing, verify swing clearance and mounting height to avoid interference with nearby structures.

Closing

Color on industrial casters isn’t decoration—it’s a shorthand for material and intended use. Define your operating conditions first (noise targets, floor type, chemical/ESD requirements, temperature, and load). Then map color to material, and use wheel diameter to optimize effort, obstacle-crossing, floor protection, and noise. With this sequence, you’ll make reliable choices in most environments.

HICKWALL has deep shop-floor experience as a specialized caster manufacturer. We supply casters in rubber, polyurethane (PU), nylon, and high-performance compounds, with options for conductive/ESD, high-temperature, food-grade, and custom diameters/durometers. Contact us for selection advice, and let us help you strike the right balance between efficiency, service life, and maintenance cost.

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