Table of Contents
What Is Durometer?
Durometer is a measurement of material hardness, specifically how resistant a material is to permanent indentation. For roller skate wheels, we use the Shore A scale, which ranges from 0 (gel-soft) to 100 (rock-hard). The number stamped on your wheels (e.g., "82A") tells you exactly where on this scale your wheels sit.
Why does this matter? Because wheel hardness directly controls the trade-off between grip and speed. A softer wheel deforms more on contact, creating a larger contact patch — more surface area touching the ground means more friction (grip) but slower speed. A harder wheel maintains its shape, creating a smaller contact patch — less friction means faster rolling but less grip.
Complete Durometer Comparison Chart
| Durometer | Feel | Grip | Speed | Best Surface | Typical Use |
|---|---|---|---|---|---|
| 78A | Very soft | ⭐⭐⭐⭐⭐ | ⭐⭐ | Rough asphalt, gravel | Outdoor quad, beginners |
| 80A | Soft | ⭐⭐⭐⭐ | ⭐⭐⭐ | Outdoor asphalt | Kids outdoor, comfort cruise |
| 82A ⭐ | Medium | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ | Indoor + outdoor | Fitness, recreational, most popular |
| 85A | Firm | ⭐⭐⭐ | ⭐⭐⭐⭐⭐ | Smooth outdoor, indoor | Slalom, freestyle, triskate |
| 90A | Hard | ⭐⭐ | ⭐⭐⭐⭐⭐ | Polished indoor only | Competition slalom, speed |
78A–80A: Soft Wheels — Maximum Grip
Soft wheels are the shock absorbers of the skating world. They deform on contact with rough surfaces, absorbing bumps and cracks that would be jarring on harder wheels. The trade-off is lower top speed and faster wear.
✓ Best For
- • Rough outdoor asphalt & sidewalks
- • Adult beginners (more grip = confidence)
- • Kids' outdoor quad skates
- • Roller derby on wood/sport court floors
✗ Avoid For
- • Indoor polished surfaces (too slow)
- • Long-distance skating (excessive drag)
- • Speed or competitive use
82A: The Universal Standard ⭐
82A is the single most popular wheel hardness in the roller skate industry, and for good reason: it sits at the exact sweet spot where grip, speed, comfort, and durability are balanced. If you're unsure what to choose, 82A is almost always the right answer.
At Qolo, approximately 65% of our production volume uses 82A wheels. It's our standard specification for fitness inline skates (GW-901D, GW-083A), quad roller skates (GW-8000 Vintage, GW-NING), and adjustable kids' inline skates.
85A: Performance & Freestyle
85A wheels are the threshold into performance territory. They provide noticeably less grip than 82A, which in slalom skating is actually a feature — reduced grip allows deliberate slides and spins that softer wheels would resist.
Our urban triskate (GW-FSK Big Wheels) uses 85A on its 110mm wheels for the optimal speed-to-grip ratio at commuting velocities. The freestyle models (GW-FSK, GW-F1) ship with 85A as standard, with 90A available as an OEM option.
90A: Competition Only
90A wheels should only be used on polished indoor surfaces — competition slalom halls, indoor rinks with sport court or polished concrete. On outdoor asphalt, 90A wheels have virtually zero grip and transmit every bump directly to the skater's joints.
We produce 90A wheels exclusively as an OEM customization for competition-grade skate brands. They are not our standard spec on any production model.
Wheel Size vs. Hardness: How They Interact
Wheel diameter and durometer work together. A larger wheel rolls faster (more leverage per rotation) and handles bumps better, while a harder wheel reduces rolling resistance. Understanding both factors helps you make the right choice:
| Setup | Wheel Size | Hardness | Speed | Comfort | Use Case |
|---|---|---|---|---|---|
| Kids Beginner | 54-64mm | 80A | Low ✓ | High | Safe learning speed |
| Youth All-Round | 72-76mm | 82A | Moderate | High | Outdoor recreation |
| Adult Fitness | 80-84mm | 82A | Moderate-High | High | Park trails, fitness |
| Slalom Pro | 76/80mm | 85-90A | High | Low | Competition |
| Urban Triskate | 3×110mm | 85A | Very High | Moderate | City commute |
| Quad Outdoor | 58-62mm | 82A | Low-Moderate | High | Rink, social skating |
Wheel Maintenance & Rotation
Wheels wear unevenly — the inside edges wear faster because that's where most skating push-off force is applied. Regular wheel rotation extends wheel life by 30-50%:
Inline Skate Rotation
Every 20-30 hours of skating:
- 1. Remove all 4 wheels
- 2. Swap wheel 1 ↔ wheel 3 (flip inside-out)
- 3. Swap wheel 2 ↔ wheel 4 (flip inside-out)
- 4. Inspect for flat spots or core separation
When to Replace
- • Diameter worn below 70% of original
- • Visible flat spots or uneven edges
- • PU core separating from hub
- • Wheels vibrate or make noise at speed
- • Noticeably reduced grip even after rotation
Frequently Asked Questions
What does the 'A' number mean on roller skate wheels?
The 'A' number (e.g., 82A) refers to the Shore A durometer scale, which measures the hardness of polyurethane (PU) rubber. Lower numbers (78A) = softer, more grippy. Higher numbers (90A) = harder, faster. Most recreational skate wheels fall between 78A and 90A.
What is the best wheel hardness for outdoor roller skating?
For outdoor asphalt and pavement, 82A is the most versatile choice — it provides good grip, decent speed, and reasonable durability. For very rough surfaces, drop to 78A-80A for more shock absorption. For smooth bike paths, 85A gives better speed without sacrificing too much grip.
What is the difference between 82A and 85A wheels?
82A wheels are softer, providing more grip, vibration dampening, and comfort on rough surfaces — ideal for general outdoor skating. 85A wheels are harder, offering less grip but faster speed, better energy return, and longer wear life — designed for smooth surfaces and performance skating.
Do softer wheels wear out faster?
Yes. Softer PU compound (78A-80A) deforms more under load, creating more contact patch area but also more material wear. A set of 78A outdoor wheels might last 200-400km, while 85A wheels on smooth surfaces can last 600-1000km. Rotation pattern (swapping wheel positions) extends lifespan by 30-50%.
Can I mix different hardness wheels on the same skate?
Yes — this is actually a common technique in slalom skating. A 'rockered' setup might use 85A on the center wheels and 82A on the front/rear for differential grip. However, for beginners, we recommend using matched sets (all same hardness) for predictable handling.