TEN THINGS YOU NEED TO KNOW ABOUT INNER TUBES

(1) Synthetics. Inner tubes are a mix of natural and synthetic rubber. Natural rubber is more pliable and offers better resistance to punctures, but synthetic rubber is cheaper.

(2) Thin versus thick. For a motorcycle manufacturer, the inner tubes are an easy place to save weight and money. Most bikes come stock with thinner and cheaper tubes.

(3) Sizing. Having the proper size inner tube for the tire is important for performance and preventing pinches. An inner tube that is too small for a given tire will have to be overinflated to make up the difference in size. Overinflation weakens the ability of the inner tube to resist damage. It is possible to run a smaller tube to save weight, but it isn't recommended.

(4) Performance. Inner tubes play a large role in the feel and performance of the tire. Inner tubes must be the correct shape and size to sit flush against the sidewall to give a good, consistent feel. If there are places where the inner tube isn't in contact, the tire will feel mushy.

(5) Heat. Inflating an inner tube to the proper pressure not only ensures more sidewall strength, but also prevents pinch flats.

(6) Weight. Inner tubes are available in a variety of thicknesses to provide the appropriate amount of protection against flats. A thin inner tube is approximately 1.3mm to 1.5mm thick. A heavy-duty tube is around 2mm to 3mm thick. And a super-heavy-duty tube is 3.5mm to 5mm thick.

(7) Powder. If an inner tube isn't installed properly, it can fail. Using powder on the inner tube during installation will reduce friction between the inner tube and the tire's carcass to help the tube last longer.

(8) Valve stem. The valve stem is the weak point of a tube. It is vulnerable to damage and leaks. The valve stem is vulcanized to the tube and can be torn off if the tire spins on the rim, so be sure the rim lock is properly installed.

(9) Contaminants. An inner tube is made to handle the abuse of a tire carcass, but not the outside elements. If water or dirt gets between the tire and tube, it will grate against the inner tube. Be sure that contaminants can't get in through the rim lock or valve stem holes.

(10) Lifespan. Even if your inner tube hasn't gone flat, it can wear out. To know when to replace a tube, look for chaffing, strings of rubber, discoloring (an old tube gets darker) or fading of any writing on the tube.