A method is disclosed for controlling the speed of a curved rotatably driven laying pipe through which a longitudinally moving product is directed to exit from the delivery end of the pipe as a helical formation of rings. The method comprises determining the maximum and minimum internal radii Rmax, Rmin of the pipe at the location of the maximum radius R of the pipe as measured from its rotational axis; continuously measuring the velocity Vp of the product entering the laying pipe; and, controlling the rotational speed of the laying pipe such that the rotational velocities Vmax, Vmin of the pipe at said maximum and minimum internal radii bracket a range containing the velocity Vp of the product.