Got my 4 year old a 16" Spesh Hot rock last xmas. Probably the best starter bike you can buy. Alloy frame,forks ahead stem and bars comes speced with back pedal brake which I belive is the best thing for tiny kiddie hands (he is already drifting it into corners!) Also as you have may have seen they have well tough stabz (getting on for 1/4 of the bikes weight!)