This week on my mountain bike on a mountain bike cut the tire with a sharp stone. I applied the patch to the inner side panel, when I pumped air out of the CO2 can it lasted a few seconds but didn't last. Maybe I didn't clean the sidewall enough (latex holes in the tire). Or maybe it was a tear that was too big. My advice is to take a patch along with a spare camera. Don't forget CO2 cartridges or at least a mini pump.