Each brand canopy frame is different and has their own distinctive features and process of accurately measuring. Somewhere on your frame or wheel there should be a manufacturer’s stamp or ID/Part number. If you are unable to locate any markings on your frame, we always welcome you to email us images of your frame without the canvas and we can help to identify what brand/style you have. Also, please keep in mind, while the wheel may indicate your lift is made by a certain manufacturer, it is possible the frame has been replaced throughout its lifetime. When sending images, please send a full front view and full side view without the canvas to email@example.com so we may help you further and guide you to measuring correctly.