The short version
Three mums, three different answers, and the one thing all of them agreed on.
What happened
He's started eyeing the cycles in the park with a seriousness that tells me this is coming. I asked around before we get into the shop, and got three different answers and one thing everyone agreed on.
[Name] swears by the balance bike: no pedals, feet on the ground, and her son went straight to a pedal cycle at five without ever using training wheels. [Name] said a balance bike was a lot of money for something used for a year, and training wheels on a normal cycle did the same job in their building's parking lot.
[Name] said forget the cycle, think about where he'll ride it. In their society the only flat stretch was the driveway, and the cycle lived on the balcony for most of the year. That one stopped me. I've been looking at our road since.
The thing all three agreed on: the helmet, from the very first ride, before any habit forms. [Name] said she bought one with a dial at the back so it fits as his head grows, and that the cheap ones from the toy shop slid over his eyes.
What I'm checking: a helmet that sits level and snug with the strap making a V under each ear, a cycle he can stand over with both feet flat, and an actual place within walking distance to ride it. When we get there, this gets rewritten from our own driveway.
The American Academy of Pediatrics recommends a properly fitted helmet on every ride from the first one: level on the head, low on the forehead, straps forming a V under the ears, snug enough not to move. For the bike itself, the child should be able to stand over the frame with both feet flat on the ground.
AAP HealthyChildren, Bicycle helmets: what every parent should know. SourceProduct details are as we used them; the version on sale now may differ. Check the exact model and the manufacturer's instructions.