Very light frame approx 7 kg ultra strong in glass fibre reinforced polyamide the parabolic rollers 85mm in diameter in the middle and 100mm at the sides make it easy to keep balance on the bicycle maximum control and ease of pedalling the wheel is guided towards the middle of the roller the perfectly smooth surface of the rollers and the compound in anti static plastic material reduce noise and tyre wear platform incorporated in the structure for easier mounting and dismounting com