Well, this brings up a sore subject. I gladly threw my 2003 Biesse B3 away after only 25 hours on the chassis. It broke at the rear bearing hangers on both sides of the frame rails. Of course I stripped it of all valuable hardware except that vulnerable lower steering shaft bearing that would wear out after 3 hours of use and is different than any kart made. I did manage to retro-fit the 50mm axle rear brake assembly onto a 40mm axle kart.