Because the World Never Stops Turning... Grant-Shelton Worldwide Tire is committed to providing quality products for the geophysical field. With over 25 years combined in the geophysical field, Mike Grant and Mike Shelton possess the knowledge and experience required to supply geophysical companies with the applicable product. Grant-Shelton Worldwide Tire travels the globe and strives to meet the demands and diverse needs of its customers. They ensure superior service and product availability to each client.