Last week I had a flat after running over a piece of glass. My rear tire (a 700x28 Mavic Yksion Elite Guard) had a cut of about 5mm on the exterior side, and 2.5mm on the interior of the tire. I repaired the tube and got back home, but I was quite sure I could see a bit of tube through the tire (it was not bulging through, but the rubber of the tube was visible with a flashlight).

I needed to use the bike before having had time to buy a new tire (I use the bike for a 35km commute), so I decided to stick a inner tube patch on the inside of it to protect the inner tube, and glued a really small piece of rubber from an old tire inside the cut from the outside side to prevent dirt getting in. Since then, I've done 200km on the tire with no adverse effects. The cut has not grown, the tire has no visible deformation, there were no wires visible in the hole before patching it, the repair seems to be holding up well, and while riding it feels totally smooth... so now I'm thinking if it's really necessary to replace it. But at the same time I'm also wondering if it's really safe to keep running the tire vs buying a new one... the tire is in good shape and almost no wear, so I'd prefer to keep it if possible, but I'm also not keen on the idea of it blowing out at 70kph, or while leaning on a twisty road.

What do you think?