Tim37 wrote on 06/28/12 at 08:52:58:i asked a good friend of mine about a "new" tire i had put up in my shed for a bike. he paciently explained to me. "if you have a blow out on a car your probably gonna be late for work, if you have a blow out on a bike your probably gonna get to ride in a ambulance. now is saving a 100 bucks worth it?"
I've never mounted "old tires", but I've had tires that were already 3 to 5 years old on certain bikes I rarely rode. These tires worked fine and I didn't have a problem with them. However, I have had three blowouts all due to road hazards; two on the back and one on the front. The back blowouts were bad as the bike becomes VERY unstable and "squirrelly", but I did manage to slow, recover control, and stop. The front tire is another story, and I ended up dumping the bike after I had slowed to about 25mph. Unfortunately, that time my wife was riding behind, but we both were OK, with only some minor bruises and scrapes.
The problem is the flat tire loses tracking ability and will try to roll off the rim due to side forces created by you attempting to steer. In fact, to say you even have steering, is somewhat of an exaggeration. Try to imagine hitting a foot deep slippery mud hole (mud, not muddy water), and you have some idea. The key thing is, like so many other situations, CONSERVATION OF MOMENTUM is the key! DO NOT try the normal procedures you would try when attempting to stop. This means no heavy braking (if any at all), keeping the bike in as straight a line as possible, and shifting your weight back-n-forth to try and stay upright. If you're lucky, you will still be sitting on the seat when the bike finally stops.