I use Slime in all my bikes, and also Mr. Tuffy liners, since we have a huge crop of goat head thorns where I ride. Yesterday, a friend and I rode 34 miles. I flatted half way, with a big mess of Slime oozing from a 1/4" gash in the back tire. Glass? Didn't find anything. Put in the spare tube, no Slime, went a few miles and my friend flatted. No liner, no Slime, just a Kevlar belted tire. Fixed that, went a few miles, and my new tube flatted. Pulled a big thorn out of the other tire at that time, oozed a little slime and sealed up. Fixed the second flat and finished the ride, last mile on a very low tire, new tube punctured again. Loaded our bikes in my van, as it was so late by then that I gave him a ride home. Good thing I did, his bike flatted again as we were loading. Conclusion: Slime stops small leaks in high pressure tires, but not big ones. Belted tires are better than liners. Nothing really stops goat heads. Also, if you do go to patch a Slimed tube, immersing it in water will open up all the leaks the stuff has plugged, making it look like a sieve. Too many holes to even consider patching, just pitch it.