i-Size Child Seats (UN R129)
i-Size is a child seat standard that uses child height and requires ISOFIX and side impact testing.
What is i-Size Child Seats (UN R129)?
It is based on UN Regulation 129. It keeps children rear-facing longer. It replaced older weight-based groups. Under i-Size, children travel rear-facing until at least 15 months, which better protects the head and neck. Seats are classified by the child's height rather than weight. Older R44 seats remain usable where national rules allow, but have been phased out of sale in the EU.
How it works
Seats are tested for frontal and side impacts.
Why it matters for your car
Check fitting lists. Follow height limits.
Other terms
- A/C Recharge (Air Conditioning Service)
- Aftermarket Parts
- Charge-sustaining Mode (Hybrid Mode)
- Cruise Control
- Door Hinge
- Exhaust Leak
- Expansion Valve (Orifice Tube)
- Heated Windscreen
- Injector Coding
- Instrument Cluster
- Keyless Entry And Start
- Oxygen Sensor (Lambda Sensor)
- Payload
- Snow Socks (Textile Snow Chains)
- Top Dead Centre (TDC)
- Torque Curve
- Tread Wear Pattern
- Tyre Puncture Repair (Plug And Patch)
- Underbody Protection
- Wheel Offset (ET)