I am an OK mechanic when it comes to working on my bike. I know how to put in a new bottom bracket or headset and I can even build wheels. But, more importantly, I know what I don't know. That means that when I come across something that I haven't done before I either study the procedures very carefully until I understand what needs to be done or I realize I can't figure it out and take my bike to my local bike shop(LBS).
Knowing what you don't know is really the key. We can't know everything, but we can learn. Well, we can usually learn. But, those times when my head hurts, I take my bike to a professional mechanic. I am not trying to pat myself on the back. It just makes sense to do what you can do and leave the rest for somebody else.
OK. That's probably pretty obvious advice and it really isn't what I was writing about. But, what I really wanted to write about is totally-related so what the heck.
A couple of days ago, while descending Kings Mountain Road here in the Silicon Valley, I got a rear flat. I only discovered the flat while I was trying to make a sweeping right turn at speed. When my rear wheel started washing out I knew I was in for some major anxiety. The fact that I kept the bike upright is probably more a result of good luck than great bike handling skills, but whatever the reason, I kept the rubber side down.
The real problem came after I removed the tire and was running my fingers through the inside of the tire to try and find what caused the puncture. When the jagged piece of glass shard poking through the casing of the tire sliced through two of the fingertips on my right hand I knew I had most likely found the problem.
Of course, with my fingers bleeding like a stuck pig, my flat tire was no longer my biggest problem. Luckily for me, a couple of cyclists passing by had a couple of bandages. I made it home in one piece, but four days later my tips are still oozing.
So, after all this babbling, the point here is, don't run your fingers through the inside of a tire after you have flatted. Use a piece of cloth or do direct visual inspection. Just avoid any method that might allow direct contact between your body and the item which caused your flat tire. Take my word for it. Ouch!