Sole Systems
Six sole families, one supplier.
Rubber, foamed rubber, TPR, injection and two ways of marrying a rubber outsole to an EVA midsole. Specify the performance the shoe needs and the material decision follows from it.
One material, two, or two made as one.
The six systems in section. A table makes the combination sole and the one-piece sole look like the same product; they are not, and the difference is the line across the middle of the fourth drawing. Proportions are schematic: section depth is set by your last and your brief, not by us.
Rubber Outsole
- Vulcanised rubber
One material, tread cut into it. Everything the sole does, the compound does.
Rubber Foam Sole
- Foamed rubber
Still one material. The foam is blown through the whole section, which is where the weight goes.
TPR Sole
- Thermoplastic rubber
One material, injected rather than cured. Fast cycles, and regrind goes back in.
Rubber / EVA Combination Sole
- EVA midsole
- Rubber outsole
Two parts moulded separately and bonded. The join is an interface; it is what peel testing is for.
One-Piece Moulded RB + EVA
- EVA section
- Rubber section
Same two materials, formed in one mould as one part. No interface, so nothing to delaminate.
IP Injection Sole
- Injection phylon
Injected into a closed tool, so the dimension repeats. One material, high volume.
Rubber, TPR or an EVA midsole?
Most sourcing conversations open with the wrong question, which of the shoe materials is best. There is no best; there is only what the shoe has to survive, at what weight, for what price. Here is how the four sole families actually trade off against each other.
| Material | Hardness | Density | Abrasion | Strengths | Trade-off |
|---|---|---|---|---|---|
| Vulcanised rubber | 30–90 Shore A (typically 50–65) | Highest of the four | Best wear life | Abrasion, wet grip, heat resistance | Heaviest; steel tooling and longer cure cycles |
| Foamed rubber | 40–65 Shore A | Lower than solid rubber | Good | Rubber wear behaviour at reduced weight | Less dimensionally stable than solid rubber |
| TPR | 40–80 Shore A (40–55 casual, 50–65 urban) | Light | DIN/ISO 40–160 mm³ | Fast cycles, clean colour, sprue regrind | Loses grip and flexibility at low temperature |
| EVA sole stock | 20–35 Shore C | 80–120 kg/m³ | DIN/ISO 120–400 mm³ | Lightest, best cushioning and rebound | Compression set over time; poor as a bare outsole |
The windows Hongsole holds
Our own figures, not the category’s, measured on the compounds we run in production, by what the sole has to do.
| Application | Hardness | Density |
|---|---|---|
| Rubber outsole, casual / lifestyle | 60–65 Shore A | 1.15 g/cm³ |
| Rubber outsole, safety / work | 65–70 Shore A | 1.15 g/cm³ |
| Foamed rubber outsole | 60–65 Shore A | 0.40 g/cm³ |
| TPR outsole | 60–65 Shore A | 1.00 g/cm³ |
| EVA sole, casual / slipper | 55–60 Shore C | 0.25 g/cm³ |
| EVA midsole, sport / running | 40–45 Shore C | 0.20 g/cm³ |
Rubber and TPR are specified in Shore A; EVA in Shore C. The two scales are not interchangeable, and a spec sheet that mixes them will not survive a technical review.
Rubber/EVA combination and IP injection soles are quoted per programme: the two layers carry different targets, so a single figure would tell you nothing. Send the brief and we will confirm the window against your compound.
Choosing between the big three?Read EVA vs rubber vs TPR soles: how to choose →
Find your shoe, then the sole follows.
Six footwear categories, the sole systems that suit each, and the tests that decide whether a sole passes for that use. Start here if you know the shoe better than the material.
Running & Athletic
Cushioning under the forefoot, rubber only where the shoe wears
- Sole systems
- Rubber / EVA combination · one-piece moulded
Outdoor & Hiking
Deep lug geometry, wet rock grip, cold flexibility
- Sole systems
- Vulcanised rubber
Work & Safety
Slip, heat and fuel-oil exposure; long wear life on hard floors
- Sole systems
- Vulcanised rubber · rubber / EVA combination
- Tests that gate it
- EN ISO 20345:2022 (slip now mandatory, SR marks the enhanced test) · HRO · FO
Casual & Lifestyle
Weight, colour fidelity and unit cost at seasonal volumes
- Sole systems
- TPR · foamed rubber
- Tests that gate it
- Colour hold · shrinkage & yellowing · abrasion
Court & Indoor
Grip without transferring pigment to the floor
- Sole systems
- Non-marking rubber
- Tests that gate it
- Non-marking / scuff (SATRA TM223) · abrasion
School & Children's
Light, latex-free, softer compounds for younger age groups
- Sole systems
- TPR
- Tests that gate it
- Hardness SATRA TM205 · chemical compliance (REACH SVHC, Prop 65)
Not sure which system fits?
Describe the shoe and what it has to survive. We come back with a material recommendation before you commit to tooling.