# Tyre size

> A tyre size is the code giving tread width (mm), aspect ratio (%) and rim diameter (inches), e.g. 120/70-17.

- **Also known as:** Lastik ebatı, Lastik ölçüleri, Tire size, Tyre size
- **Turkish term:** Lastik ölçüsü
- **Category:** [Motorcycle Tyres](https://motorsikletparcasi.com/en/category/motorcycle-tyres)
- **Page:** https://motorsikletparcasi.com/en/glossary/tyre-size

In 120/70-17, 120 is the width, 70 the sidewall height as a percentage of the width (70% = 84 mm) and 17 the rim diameter. "R" marks radial and "-" bias-ply construction. The load/speed index that follows (e.g. 58P) shows load capacity and the permitted speed class.

In older inch sizes such as 3.00-10, the width is given in inches. A different size can affect the speedometer and how [ABS](https://motorsikletparcasi.com/en/glossary/abs) reads wheel speed; check the effect with our [tyre size calculator](https://motorsikletparcasi.com/en/tools/tire-size-calculator).

## Related terms

- [Tyre pressure](https://motorsikletparcasi.com/en/glossary/tyre-pressure): Tyre pressure is the air pressure inside the tyre, measured in bar or psi; it directly affects grip, braking distance, tyre life and fuel use.
- [Wheel rim](https://motorsikletparcasi.com/en/glossary/wheel-rim): A wheel rim is the metal hoop the tyre sits on; it is joined to the hub by spokes or cast spokes to form the wheel.
- [ABS (anti-lock braking system)](https://motorsikletparcasi.com/en/glossary/abs): ABS (anti-lock braking system) detects a wheel about to lock under hard braking and modulates brake pressure many times a second to keep grip.

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- Source page: https://motorsikletparcasi.com/en/glossary/tyre-size
- Last updated: 2026-10-09
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