What does ETRTO mean?
The ETRTO system is the most accurate and reliable way to identify a bike tyre size. ETRTO stands for European Tyre and Rim Technical Organisation and removes the confusion created by inch and French sizing.
An ETRTO size is written as width – rim diameter, both measured in millimetres. For example:
- 54-584 → tyre width: 54 mm
- 584 → inner tyre diameter (rim size)
Unlike inch markings, the ETRTO number precisely defines the rim compatibility. You can usually find the ETRTO size printed on the tyre sidewall.
Understanding ETRTO sizing is essential when choosing replacement tyres, especially for modern MTB, gravel, cargo and e-bike wheels.
ETRTO, inch and French tyre sizes explained
Bike tyres are commonly marked using three different systems:
- ETRTO (recommended) – exact rim compatibility
- Inch sizes – traditional, but often ambiguous
- French sizes – mainly used on road and vintage bikes
Below you'll find a full reference table showing how ETRTO sizes correspond to inch and French markings across all common wheel diameters.
Tip: When in doubt, always match the ETRTO rim diameter first. Tyre width can usually vary slightly depending on rim width and riding style.
Do I need special tyres for e-bikes?
For standard road and urban e-bikes limited to 25 km/h, special tyres are not legally required.
However, e-bikes are heavier and place greater load on tyres. For better durability, comfort and puncture protection, we strongly recommend using e-bike-rated tyres.
Popular choices for urban and trekking e-bikes include durable, reinforced models designed to handle higher weight and torque.
For E-MTB use, the stresses are significantly higher due to off-road terrain and motor assistance. In this case, dedicated e-bike MTB tyres provide better casing strength, grip and sidewall protection.
Using tyre sealant or sealant-filled inner tubes can further reduce puncture risk and improve reliability.
What should I know about speed e-bikes (up to 45–50 km/h)?
Speed e-bikes require specific tyres approved for high speeds. In Europe, tyres must carry ECE-R75 certification to be legally used on e-bikes up to 45–50 km/h.
ECE-R75 tyres are tested for:
- High-speed stability
- Heat resistance
- Load capacity
- Reliable grip at speed
Always check your tyre sidewall for the ECE-R75 marking when riding a speed e-bike.
Studded tyres and winter riding
Riding on snow and ice requires maximum traction. Studded or spiked tyres are the safest option in winter conditions.
While studded tyres generate more road noise on tarmac, the dramatic improvement in grip and braking performance makes them worthwhile in icy conditions.
For cold, wet or muddy conditions without ice, tyres with an aggressive tread pattern offer excellent control and reliability.
Winter-ready tyres are especially important for commuters and riders using bikes year-round.
What is a balloon bike and balloon tyres?
A balloon bike is a city or touring bike fitted with high-volume tyres, typically between 50 and 60 mm wide.
These tyres provide natural suspension through air volume alone, delivering exceptional comfort without the need for suspension forks or seatposts.
At around 2 bar of pressure, balloon tyres roll efficiently while absorbing road vibration far better than narrow tyres.
In comparison, a standard 37 mm urban tyre often requires up to 4 bar to achieve similar rolling efficiency, resulting in a firmer ride.
Balloon tyres are ideal for everyday riding, commuting and long-distance comfort.
Choose the right tyres for your bike
Ready to choose the right tyres? Browse our full range of in-stock bike tyres across all sizes and disciplines.