Cotton tractors need enough space under the front axle to avoid damaging plants. Researchers found that by adjusting the pivot pin length and wheel sizes, they can ensure a four-wheeled cotton tractor has the right clearance above the crop. They discovered that changing these dimensions can affect how well the tractor steers and moves, so it's important to get the measurements just right. For example, a pivot pin length of 435 mm was found to be effective in providing the necessary clearance.