What is the biggest size tire you can put on a stock 1999 jeep wrangler?

The biggest tire size you can typically fit on a stock 1999 Jeep Wrangler without modifications is around 31 inches in diameter. This size provides a balance between improved traction and maintaining the vehicle's handling characteristics. However, it's important to consider factors such as wheel width and backspacing, as well as potential rubbing issues when turning. If you desire larger tires, modifications such as a lift kit may be necessary.