My tractor has 33 hp. After reading a number of reviews I decided on the Slime brand. I removed the valve core and put in some grease before deflating the tire and driving around a bit. I did the same as a preventive measure on the other side. It's been a few weeks now and it's holding air with no loss of pressure. I'm not sure how big the patched hole was, but it took a few minutes to fill with air before the tire lost air. I was very pleased with the results of this material.