Back home now going over details from our tour season and was reminded of this--a failed inner tube or "camera di aria" in Italian. Note this cheap, low-quality tube looks like it's been cut in half with scissors or a knife. Not true. It simply failed at the seam, the failure point is what is circled. A small amount of stretching pulled it completely apart! Sadly, inner tubes often get onto a shop's shelves solely based on price, a price often less than a dollar each to your dealer. He or she has a big incentive to buy the cheapest ones available since they are a high-profit item selling for $4-5 each. But inner tubes are like condoms, they need to do only one thing---SEAL THEIR CONTENTS INSIDE. If they fail, the consequences can be VERY serious! We use Michelin-brand tubes--period. They cost quite a bit more but NEVER have I seen one fail. Insist your bike shop stock and sell quality tubes, your (or the guy riding next to you) life could depend on it! Disclaimer, we are not sponsored in any way by Michelin, in fact we prefer Vittoria when it comes to tires.