One day recently when I was about 800 meters from work (for the American audience that's just over 2,600 foot long hot dogs laid out end to end) I noticed that my whip was riding really rough. I came to a stop to take inventory and it did not take me long to find I had achieved the first flat tire ever on my Globe Vienna. I have put over 1,100 kilometers (680 miles of foot long hot dogs) on the bike without a flat. The Nimbus 700 x 35c tires that came with it had performed admirably on the broken glass infested NYC streets.
I had almost expected a flat when it actually did happen because the night before I was riding to a restaurant I had never been to before and was paying more attention to address numbers than where I was going. One moment when I glanced at the street I realized too late that I was basically on top of a shattered glass bottle. I had no real time to react and rode straight through it.
When I returned to my whip after dinner the tires were fine but it appears that a shard of glass embedded in the tire and as I rode to work the next day the shard went deeper and deeper until the sharp fang found the innocent, soft rubber skin of the tube and the long streak of days without a flat came to an end.
Rather than change the flat on the street I just walked the few thousand hot dogs to work so I could change the flat in the comfort of my office while listening to NPR. Once ensconced in my office I took the rear wheel off and started to rotate it while pinching the tire looking for glass shards. I found several and just scraped them out with a fingernail but did not think to pick up my camera before I had completed the process.
What you see here is an innocent looking tire . . . .
But when pinched reveals a rather nasty gash where a shard was embedded.
As I continued the process of checking and prepping for re-inflation I thought it would make a good entry to note some of the steps I take when repairing a flat.
1. As already described, spin the wheel around an check for foreign material on the outside of the tire. Pinch the tire and scrape out embedded junk.
2. Do the same for the inside of the tire - check to see if foreign material is sticking through, and also look to see if there is a tear in inner wall of tire.
3. If there is a tear in the inner wall, it is a good idea to take a piece of duct tape and put it over the tear. This will help to keep the tube from possibly bulging out of the tear. If the tear is severe or is in the sidewall, you might want to consider a new tire.
4. Once I have determined that the tire is in good condition, and if I have it, I take some baby powder and spray a "glop" into the tire (see end of the orange arrow). I then rotate the tire around, gravity keeps the "glop" on the bottom, and it coats the inner wall as I rotate the tire. This helps to ensure that the tube does not bunch up and get pinched when you insert it back into the tire. I also will spray some powder into my hands and run the tube through my hands so that it is coated with powder as well.
5. The last step of course is to insert a new tube or the repaired tube and pump it up to test it out. I always recommend doing this before putting wheel back on because if it goes flat again right away, you have to go through the whole process of taking off the wheel again. Also of note, if you are rocking calliper brakes, you will need to likely deflate the tire before putting the wheel back on because the tire when inflated will sometimes not fit through the brake pads. This happened to me when I stepped up from 23c to 28c tires on my road bike with my Shimano 105 brakes. If you have disc, cantilever, or V-brakes you should be fine.
On a final note, every once in a while, especially if you ride a lot in urban areas, it is good to take preemptive measures to avoid flats caused by embedded glass. Simple instructions are as follows:
1. Crack open a beer.
2. Let the air out of your tires.
3. Rotate your wheel and pinch the tire anywhere you think foreign material is embedded.
4. If you chose to consume some nuts with your beer while doing this, make sure to put them into a bowl and use a spoon to eat them because touching nuts with your hands when using the same hands to touch a tire is a very, very bad idea.
5. When you are finished picking out the junk re-inflate your tires.
6. Finish your beer and recycle the container it came in.