Crumb rubber starts as a waste tire and ends up in athletic fields, playgrounds, asphalt, rubber mats, and dozens of industrial applications. The transformation involves several stages of mechanical processing — each one reducing the tire into smaller and cleaner material. Here's how it works.
Stage 1: Tire Collection & Sorting
The process starts with waste tire collection. Tires are gathered from tire shops, fleets, municipalities, and other generators and transported to a processing facility. On arrival, tires are sorted by type — passenger, light truck, semi, OTR — because different tire types have different rubber compositions, steel content, and processing requirements. Passenger and light truck tires are the primary feedstock for crumb rubber production.
Stage 2: Primary Shredding
Whole tires go into a primary shredder — a large industrial machine with counter-rotating shafts fitted with cutting blades. The shredder reduces whole tires into chips roughly 2–4 inches in size. At this stage, the material is called "tire-derived fuel" (TDF) chips if it's going to be used as fuel, or it continues to the next stage for crumb rubber production.
Stage 3: Secondary Shredding & Granulation
The chips from the primary shredder go through a secondary shredder or granulator, which reduces the material further — typically to 3/8" to 3/4" pieces. This stage begins to liberate the steel and fiber from the rubber matrix, making separation easier in the next stage.
Stage 4: Steel & Fiber Separation
Tires contain steel belts and fiber (nylon or polyester cords). Both must be removed before the rubber can be used as crumb. Steel is removed using powerful magnets positioned along the conveyor system. Fiber is removed using a combination of screening, air classification (blowing lighter fiber away from heavier rubber), and mechanical separation. The result is rubber granulate with minimal steel and fiber content.
Stage 5: Cracker Mill or Fine Grinding
To produce finer mesh sizes (30, 80, 100 mesh), the rubber granulate goes through a cracker mill — two counter-rotating rollers with a narrow gap that shear the rubber into smaller particles. Multiple passes through the cracker mill produce progressively finer material. For very fine powder (100+ mesh), cryogenic grinding is sometimes used — freezing the rubber with liquid nitrogen to make it brittle, then grinding it to a fine powder.
Stage 6: Screening & Sizing
The processed rubber is run through a series of vibrating screens to separate it into specific mesh sizes. "Mesh" refers to the number of openings per linear inch in the screen — so 10 mesh has larger openings (coarser rubber) and 100 mesh has very fine openings (fine rubber powder). Material that doesn't pass through the target screen goes back for additional processing.
Crumb Rubber Mesh Sizes & Applications
| Mesh Size | Particle Size | Common Applications |
|---|---|---|
| 10 mesh | ~2mm | Playground surfacing, equestrian arenas, drainage layers |
| 20 mesh | ~1mm | Athletic field infill, rubber mats, molded products |
| 30 mesh | ~0.6mm | Rubber flooring, athletic tracks, impact pads |
| 80 mesh | ~0.2mm | Asphalt rubber, sealants, industrial compounds |
| 100 mesh | ~0.15mm | Rubber powder for coatings, adhesives, specialty compounds |
Quality Control & Testing
Quality crumb rubber buyers — especially for athletic fields and playgrounds — require documentation on:
- Steel content: Maximum allowable steel wire content (typically <0.01% by weight)
- Fiber content: Maximum allowable fiber content
- Moisture content: Must be below a specified threshold to prevent clumping
- Mesh distribution: Percentage of material within the target mesh range
- Specific gravity: Relevant for infill applications where density matters
Buy Crumb Rubber from Eco Tire Solutions
We supply 10, 20, 30, 80, and 100 mesh crumb rubber to buyers across South Carolina and the Southeast. Full spec sheets and documentation available.