• Dec 19, 2025 Replace Drive Belt Lawn Mower Yth20k46 the mower’s manual or the belt’s part number printed on the existing belt, which typically matches OEM specifications. Many aftermarket options exist, but not all meet the durability and fit standards required for the YTH20K46 model. Comparing OEM vs. Aftermarket Belts OEM belts: Man By Brock Beatty