I have a large yard with thorny trees and other thorns in the ground. I've had flat tires quite a few times over the years and have tried different solutions (patches, inner tubes, slimy sealant, airless tires). Each of these solutions have been temporary and/or expensive. The problem is that I would inevitably run into more spikes. The airless tires I recently bought for the front wheels seem to have fixed the problem. I don't think anyone makes airless rear tires, probably because (1) they would be very expensive and (2) the ride would likely be too bumpy. The slime didn't work that well, and the slime is causing the wheel to rust inside. A few months ago I spilled this stuff in my current leaking rear tire on my lawnmower. I found the hole, removed the spike, but didn't patch the hole. Pumped everything up, refilled with air and let the tire run for a minute before putting it back on the tractor. Since then I have mowed the lawn three times. There was no air loss in the tire. A friend of mine with a zero radius mower had a similar air pressure issue, so I had him pump these things up on his tires. He reports the same - the tires have since been inflated. It's been about a month and I think two cuts for him.