Ready for a bike ride? Aim for 9–12 months when neck muscles support a helmet....

https://gunnerawsh736.cavandoragh.org/why-does-my-child-bike-seat-squeak-and-rattle-the-whole-ride

Ready for a bike ride? Aim for 9–12 months when neck muscles support a helmet. If your baby sits upright unsupported, front or rear rack-mounted seats work great. Before that milestone, use a trailer with an infant insert. Prioritize neck stability!