I find there are many design problems with children's bikes, and many of them lead to falls, and sometimes injuries. Maybe if children bikes looked more like scaled down adult bikes, there would be less problems.
Some problems :
- Training wheels. Yes, I know they are optional, but current ones are much narrower and more flimsy than the ones I had as a child (I digged them out and measured). Even with those, the wheelbase is too narrow and it's easy to flip on the side at 2 km/h.
Well, that was a good reason to prevent my daughter from using them, so she learned to cycle (2-wheels mode) at 4.
- Very high bottom bracket and long crancks. How come bikes with 16" wheels come with 165-mm cranks and wide (standard-width) pedals? With the 25-degree-tilt requirement, it means a very high bottom bracket, which means the saddle is either low for safe starts, or high for safe pedalling. A bike with 16" wheels should have a bottom bracket very close to the ground, say at 180 mm, so that it's easy to start and stop under full control.
- Too high handlebars. I know many kids prefer the fully upright position, and it's easier to start cycling that way, but it's almost impossible to puncture your abdomen or chest with road bars or even with the type of straight bars in use 25 years ago. Why? because they were too low for that.
Regards,