To replace the spring in your 60-inch Irvine window shade for your 2020 Forest River RV, you first need to remove the spring and measure the outside diameter of the aluminum tube it is mounted on. This measurement is essential to ordering the correct replacement spring. For a 1-inch diameter tube, you can order the appropriate spring directly from Elkhart RV Parts. They offer a selection of replacement springs specifically for Irvine roller shades. Visit their website to find the exact spring and ensure compatibility. If you need assistance or have questions about your measurement or order, Elkhart RV Parts customer service is available to help you select the correct part.