My son rode the plastic trainers off his bike so I took the wheels and bearings with the mounting bolts from a knock off Razor scooter type thing he had and mounted them on his bike they roll so fast when they hit but they are so small if he depends on them he going to fall over anyway. He has to plant a foot when he stops but when he is taking off he rests on the one to plant his feet then they dont touch again. He rode six miles yesterday and 4 of the 6 was at a blistering pace for him then he kinda bonked out, thankfully we were near the Publix so we went in for him to get a free sugar cookie and he was off again!!!