You really can't change wood shafts,...much and it isn't easy, but if not doing it means some expensive modifications, its worth a try. Wondering if the shafts really will take a new set? Ever look at a cart and wonder why the shafts curve up at the tips? That's what hapens when you store a wood shaft cart with the shafts resting on the ground instead of supporting the shafts in a level position. In time, the shafts will assume a new bend just from the pressure of the cart on the tips. Shafts and all the rest of the bent wood components on your cart all start as straight square blanks cut from a log. They are heated and hydraucally or mechanically bent in to the curved shape, then left to dry. When dry, they remain bent, but there is always the natural force trying to return that piece of wood to its original straight shape. This is especially a problem with mini sized pieces, as there is not a much wood to resist force.