What is the biggest rear tire size that can be put on a stock road king 2007 model?

The stock 2007 Harley-Davidson Road King typically accommodates a rear tire size of 180/65B16. However, some riders have successfully fitted a wider tire, such as 200/55B16, with modifications to the fender and swingarm for clearance. It's essential to ensure that any tire upgrade maintains proper handling and safety, so consulting with a professional or experienced technician is recommended before making changes.